Category Archives: .net

.net, database, microsoft, professional, software development, tech

SQLite with .NET: excellent but some oddities

I have been porting a C# application which uses an MDB database (the old Access/JET format) to one that uses SQLite. The process has been relatively smooth, but I encountered a few oddities.

One is puzzling and is described by another user here. If you have a column that normally stores string values, but insert a string that happens to be numeric such as “12345”, then you get an invalid cast exception from the GetString method of the SQLite DataReader. The odd thing is that the GetFieldType method correctly returns String. You can overcome this by using GetValue and casting the result to a string, or calling GetString() on the result as in dr.GetValue().ToString().

Another strange one is date comparisons. In my case the application only stores dates, not times; but SQLite using the .NET provider stores the values as DateTime strings. The SQLite query engine returns false if you test whether “yyyy-mm-dd 00:00:00” is equal to “yyy-mm-dd”. The solution is to use the date function: date(datefield) = date(datevalue) works as you would expect. Alternatively you can test for a value between two dates, such as more than yesterday and less than tomorrow.

Performance is excellent, with SQLite . Unit tests of various parts of the application that make use of the database showed speed-ups of between 2 and 3 times faster then JET on average; one was 8 times faster. Note though that you must use transactions with SQLite (or disable synchronous operation) for bulk updates, otherwise database writes are very slow. The reason is that SQLite wraps every INSERT or UPDATE in a transaction by default. So you get the effect described here:

Actually, SQLite will easily do 50,000 or more INSERT statements per second on an average desktop computer. But it will only do a few dozen transactions per second. Transaction speed is limited by the rotational speed of your disk drive. A transaction normally requires two complete rotations of the disk platter, which on a 7200RPM disk drive limits you to about 60 transactions per second.

Without a transaction, a unit test that does a bulk insert, for example, took 3 minutes, versus 6 seconds for JET. Refactoring into several transactions reduced the SQLite time to 3 seconds, while JET went down to 5 seconds.

.net, microsoft, software development, tech

Should you convert your Visual Basic .NET project to C#? Why and why not…

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When Microsoft first started talking about Roslyn, the .NET compiler platform, one of the features described was the ability to take some Visual Basic code and “paste as C#”, or vice versa.

Some years later, I wondered how easy it is to convert a VB project to C# using Roslyn. The SharpDevelop team has a nice tool for this, CodeConverter, which promises to “Convert code from C# to VB.NET and vice versa using Roslyn”. You can also find this on the Visual Studio marketplace. I installed it to try out.

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Why would you do this though? There are several reasons, the foremost of which is cross-platform support. The Xamarin framework can use VB to some extent, but it is primarily a C# framework. .NET Core was developed first for C#. Microsoft has stated that “with regard to the cloud and mobile, development beyond Visual Studio on Windows and for non-Windows platforms, and bleeding edge technologies we are leading with C#.”

Note though that Visual Basic is still under active development and history suggests that your Windows VB.NET project will continue running almost forever (in IT terms that is). Even Visual Basic 6.0 applications still run, though you might find it convenient to keep an old version of Windows running for the IDE.

Still, if converting a project is just a right-click in Visual Studio, you might as well do it, right?

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I tried it, on a moderately-size VB DLL project. Based on my experience, I advise caution – though acknowledging that the converter does an amazing job, and is free and open source. There were thousands of errors which will take several days of effort to fix, and the generated code is not as elegant as code written for C#. In fact, I was surprised at how many things went wrong. Here are some of the issues:

The tool makes use of the Microsoft.VisualBasic namespace to simplify the conversion. This namespace provides handy VB features like DateDiff, which calculates the difference between two dates. The generated project failed to set a reference to this assembly, generating lots of errors about unknown objects called Information, Strings and so on. This is quick to fix. Less good is that statements using this assembly tend to be more convoluted, making maintenance harder. You can often simplify the code and remove the reference; but of course you might introduce a bug with careless typing. It is probably a good idea to remove this dependency, but it is not a problem if you want the quickest possible port.

Moving from a case-insensitive language to a case-sensitive language is a problem. Visual Studio does a good job of making your VB code mostly consistent with regard to case, but that is not a fix. The converter was unable to fix case-sensitivity issues, and introduced some of its own (Imports System.Text became using System.text and threw an error). There were problems with inheritance, and even subtle bugs. Consider the following, admittedly ugly and contrived, code:

image

Here, the VB coder has used different case for a parameter and for referencing the parameter in the body of the method. Unfortunately another variable with the different case is also accessible. The VB code and the converted C# code both compile but return different results. Incidentally, the VB editor will work very hard to prevent you writing this code! However it does illustrate the kind of thing that can go wrong and similar issues can arise in less contrived cases.

C# is more strict than VB which causes errors in conversion. In most cases this is not a bad thing, but can cause headaches. For example, VB will let you pass object members ByRef but C# will not. In fact, VB will let you pass anything ByRef, even literal values, which is a puzzle! So this compiles and runs:

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Another example is that in VB you can use an existing variable as the iteration variable, but in C# foreach you cannot.

Collections often go wrong. In VB you use an Item property to access the members of a collection like a DataReader. In C# this is omitted, but the converter does not pick this up.

Overloading sometimes goes wrong. The converter does not always successfully convert overloaded methods. Sometimes parameters get stripped away and a spurious new modifier is added.

Bitwise operators are not correctly converted.

VB allows indexed properties and properties with parameters. C# does not. The converter simply strips out the parameters so you need to fix this by hand. See https://stackoverflow.com/questions/2806894/why-c-sharp-doesnt-implement-indexed-properties if the language choices interest you.

There is more, but the above gives some idea about why this kind of conversion may not be straightforward.

It is probably true that the higher the standard of coding in the original project, the more straightforward the conversion is likely to be, the caveat being that more advanced language features are perhaps more likely to go wrong.

Null strings behave differently

Another oddity is that VB treats a String set to null (Nothing) as equivalent to an empty string:

Dim s As String = Nothing

If (s = String.Empty) Then ‘TRUE in VB
     MsgBox(“TRUE!”)
End If

C# does not:

String s = null;

   if (s == String.Empty) //FALSE in C#
    {
        //won’t run
    }

Same code, different result, which can have unfortunate consequences.

Worth it?

So is it worth it? It depends on the rationale. If you do not need cross-platform, it is doubtful. The VB code will continue to work fine, and you can always add C# projects to a VB solution if you want to write most new code in C#.

If you do need to move outside Windows though, conversion is worthwhile, and automated conversion will save you a ton of manual work even if you have to fix up some errors.

There are two things to bear in mind though.

First, have lots of unit tests. Strange things can happen when you port from one language to another. Porting a project well covered by tests is much safer.

Second, be prepared for lots of refactoring after the conversion. Aim to get rid of the Microsoft.VisualBasic dependency, and use the stricter standards of C# as an opportunity to improve the code.

.net, development, microsoft, software development, visual studio

What is happening with desktop development on Windows and will WPF be upgraded at last?

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Once upon a time all Windows development was desktop development. Then there was web development, but that was a server thing. Then in October 2012 Windows 8 arrived, and it was all about full-screen, touch control and Store-delivered applications that were sandboxed and safe to run. Underneath this there was a new platform-within-a-platform called the Windows Runtime or WinRT (or sometimes Metro). Developing for Windows became a choice: new WinRT platform, or old-style desktop development, the latter remaining necessary if your application needed more features than were available in WinRT, or to run on Windows 7.

Windows 8 failed and was replaced by Windows 10 (July 2015), in large part a return to the desktop. The Start menu returned, and each application again had a window. WinRT lived on though, now rebranded as UWP (Universal Windows Platform). The big selling point was that your UWP app would run on phones, Xbox and HoloLens as well as PCs. It was still locked down, though less so, and still Store-delivered.

Then Microsoft decided to abandon Windows Phone, a decision obvious to Microsoft-watchers in June 2015 when ex-Nokia CEO Stephen Elop left Microsoft, just before the launch of Windows 10, even though Windows Phone was not formally killed off until much later. UWP now had a rather small u (that is, not very universal).

In addition, Microsoft decided that locking down UWP was not the way forward, and opened up more and more Windows APIs to the platform. The distinction between UWP and desktop applications was further blurred by Project Centennial, now known as Desktop Bridge, which lets you wrap desktop applications for Store delivery.

Perhaps the whole WinRT/UWP thing was not such a good idea. A side-effect though of all the focus on UWP was that the old development frameworks, such as Windows Forms (WinForms) and Windows Presentation Foundation (WPF), received little attention – even though they were more widely used. Some Windows 10 APIs were only available in UWP, while other features only worked in WinForms or WPF, giving developers a difficult decision.

The Build 2018 event, which was on last week in Seattle, was the moment Microsoft announced that it would endeavour to undo the damage by bringing UWP and desktop development together. “We’ve taken all the UI stacks and merged them together” said Mike Harsh and Scott Hunter in a session on “Modernizing desktop apps” (BRK3501 if you want to look it up).

According to Harsh and Hunter, Windows desktop application development is increasing, despite the decline of the PC (note that this is hardly a neutral source).

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So what was actually announced? Here is a quick summary. Note that the announced features are for the most part applicable to future versions of Windows 10. As ever, Build is for the initial announcement. So features are subject to change and will not work yet, other than possibly in pre-release form.

Greater information density in UWP applications. WinRT/UWP was originally designed for touch control, so with lots of white space. Most Windows users though have mouse and keyboard. The spacious UWP layout looked wrong on big desktop displays, and it made porting applications harder. The standard layout is getting less dense, and a new Compact Size, an application setting, will pack more information into the same space.

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More controls for UWP. New DataGrid, Forms with data validation, Menu bar, and coming in future, Status bar, tab controls and Ribbon. The idea is to make UWP more suitable for line-of-business applications, which accounts for a large part of Windows application development overall.

New Windowing APIs for UWP. WinRT/UWP was designed for full-screen applications, not the popup-dialogs or floating windows possible in desktop applications. Those capabilities are coming though. We will get tool windows, light-dismiss windows (eg type and press Enter), and multiple windows on one thread so that they work like a single application when minimized or cycled through with alt-tab. Coming in future are topmost windows, modal windows, custom title bars, and maybe even MDI (Multiple Document Interface), though this last seems surprising since it is discouraged even in the desktop frameworks.

What many developers will care about more though is new features coming to desktop applications. There are two big announcements.

.NET Core 3.0 will support WinForms and WPF. This is big news, partly because it performs better than the Windows-only .NET Framework, but more important, because it allows side-by-side deployment of the .NET runtime. Even better, a linker will let you deliver a .NET Core desktop application as a single executable with no dependencies. What performance gain? An example shown at Build was an application which uses File APIs running nearly three times faster on .NET Core 3.0.

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XAML Islands enabling UWP features in WinForms and WPF. The idea is that you can pop a UWP host control in your WinForms or WPF application, and show UWP content there. Microsoft is also preparing wrapper controls that you can use directly. Mentioned were WebView, MediaPlayer, InkCanvas, InkToolBar, Map and SwapChainPanel (for DirectX content). There will be a few compromises. The XAML host window will be rectangular (based on an HWND) which means non-rectangular and transparent content will not work correctly. There is also the Windows 7 problem: no UWP on Windows 7, so what happens to your XAML Islands? They will not run, though Microsoft is working on a mechanism that lets your application substitute compatible Windows 7 content rather than crashing.

MSIX deployment. MSIX is Microsoft’s latest deployment technology. It will work with both UWP and Desktop applications, will support Windows 7 and 10, will provide for auto-updates, and will have tooling built into Visual Studio, as well as a packager for both your own and third-party applications. Applications installed with MSIX are managed and updated by Windows, have tamper protection, and are installed per-user. It seems to build upon the Desktop Bridge concept, the aim being to make Windows more manageable in the Enterprise as well as safer for all users, if Microsoft can get widespread adoption. The packaging format will also work on Android, Mac and Linux and you can check out the SDK here.

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Will WPF or WinForms be updated?

The above does not quite answer the question, will WPF or Windows Forms be significantly updated, other than with the ability to use UWP content? I could not get a clear answer on this question at Build, though I was told that adding support for .NET Core 3.0 required significant changes to these frameworks so it is no longer true to say they are frozen. With regard to WPF Microsoft Corporate VP Julia Liuson told me:

“We will be looking at more controls, more capabilities. It is widely recognised that WPF is the best framework for desktop development on Windows. The fact that we’re moving on top of .NET Core 3.0 gives us a path forward.”

That said, I also heard that the team would rather write code once and use it across UWP, WPF and WinForms via XAML Islands, than write new controls for each framework. That makes sense, the difficulty being Windows 7. Microsoft would rather promote migration to Windows 10, than write new UI components that work across both Windows 7 and Windows 10.

.net, development

Should you go to Microsoft Build?

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In the beginning there was the Professional Developers Conference (PDC) – the first was in 1992. They were fantastic events, with deep dives into the innards of Windows and how to develop applications on Microsoft’s platform. Much of the technology presented was in early preview and often did not work quite right; some things that were presented never made it to production, famous examples including “Hailstorm” also known as .NET My Services, and the WinFS file system originally slated for Windows Vista.

These events seemed to be a critical part of Microsoft’s development cycle. Internally teams would ready their latest stuff for a PDC session, which was then adapted and re-presented at other events around the world.

Then PDC kind-of morphed into Microsoft Build, the first of which took place in September 2011. Unlike PDC, Build was specifically focused on Windows, and was originally associated with Windows 8 and its new app platform, WinRT. Part of the vision behind Windows 8 was that it would have a strong app ecosystem and Build was about enthusing and informing developers about the possibilities.

As it turned out, the Windows 8 app ecosystem was a bit of a disaster for various reasons. Microsoft had another go with UWP (Universal Windows Platform) in Windows 10. Build in April 2015 was an amazing event, where the company appeared to be going all-out to make UWP on both desktop and mobile a success. Not only was the platform itself being enhanced, but we also got Project Centennial (deliver desktop applications via the Store), Project Astoria (compile Android apps to UWP) and Project Islandwood (compile iOS code for UWP).

Just a few months later the company made a huge about-turn. CEO Satya Nadella’s Aligning Engineering to Strategy memo signalled the beginning of the end for Windows Phone, and the departure of Stephen Elop and the dismantling of the Nokia devices acquisition. That was the end of the universal part of UWP.

Project Astoria was scrapped. The Windows Bridge for iOS (Project Islandwood) still just about exists, but its core rationale (get iOS apps to Windows Phone) is now irrelevant.

Nadella steered the company instead towards “the intelligent cloud” and to date that strategy has been successful, with impressive growth for Office 365 and Microsoft Azure.

Microsoft has announced Build 2018, in early May, I find it intriguing, given the history of Build, that Windows is not currently mentioned on the event’s home page. In the page description metadata it says:

Microsoft Build 2018, Seattle, WA May 7-9, 2018. Microsoft’s ultimate developer conference focused on cloud, artificial intelligence, mixed reality, and more.

In the main text of the page, about the only specific topics mentioned are these:

Take in keynotes by Microsoft CEO Satya Nadella and other visionaries behind the Intelligent Cloud and Intelligent Edge

That sounds like a focus on Azure and AI/ML/IoT/Big Data cloud services, and on mobile and IoT devices. It is a long way removed from the original concept of Build as all about Windows and its application platform.

Windows remains important to Microsoft, and to all of us who use it day to day. Still, if you think about cutting-edge software development today, Windows desktop applications are probably not the first thing to come to mind, nor UWP for that matter.

This being the case, it does make sense for the company to focus on its cloud services at Build, and on diverse mobile platforms through what is now an amazing range of cross-platform tools in Visual Studio.

Of course there will in fact also be Windows stuff at Build, including Windows and HoloLens Mixed Reality, Cortana skills and UWP improvements.

Still, if you can only get to one big Microsoft event in the year, Ignite in September is now a bigger deal and closer to the heart of the new (or current) Microsoft.

Let me add that these Microsoft events, whether Build or PDC, have on occasion seen some stunning announcements. Examples include the unveiling of C# and the .NET Framework, the 2003 Longhorn reveal (yes it all turned to dust), Windows 7 in 2008, and Windows 8 in 2011.

I would like to think that the company still has the capacity to surprise and amaze us; but it must be admitted that the current Build pitch is rather unexciting. Google I/O, incidentally, is on at the same time.

.net, development, tech

Microsoft introduces new feedback system for technical documentation, will delete existing comments

Microsoft is introducing a new feedback system for https://docs.microsoft.com, used for its technical documentation.

The new system, which you can already see for certain topics such as the Visual Studio IDE, is based on GitHub issues. When you leave a comment, you can specify whether it concerns documentation or product functionality.

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So far so good, but the downside is that all existing comments will be deleted:

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The statement “Old comments will not be carried over. If content within a comment thread is important to you, please save a copy.” is unhelpful. Nobody knows what comments will be useful to them in future.

Few things sap enthusiasm for community participation more than having all the past contributions into which you have put effort suddenly zapped. Nor is this the first time, as user guibirow notes:

As much I like the new system idea, I hate the fact that this is happening over and over.
It used to be a Disqus comment system, then moved to LiveFyre, then moved now to this new system, what will be the next?
The worst part of this all is that MS does not care about past content lost on these discussions, so many times I found issues described in the docs that are gone now.
Please, pay attention to your previous mistakes, don’t let the information be lost again, at lest import them as closed issue in the new system.

Sometimes progress has a cost and that is understood. However it is not impossible to migrate content from one system to another. It just takes effort.

Update: Microsoft’s Rob Eisenberg has responded with an explanation and mitigation plan regarding existing comments. He says that a straight migration of the comments is impossible:

    • There is a lot of garbage, spam and even dangerous content within existing LiveFyre comments which would violate GitHub terms of usage and our open source code of conduct, as well as cause security problems.
    • There isn’t a good way to map LiveFyre users to GitHub users and using a bot account to anonymously add comments is questionable with respect to OSS practices and GitHub terms of use.
    • For legal and privacy reasons, we cannot move user-associated data from one system to another without consent from users (GDPR).
    • LiveFyre conversations are threaded, while GitHub issues are not.
    • Placing the old comments into the GitHub Issues system would derail the entire GitHub Issues workflow for both customers and employees and muddle the data.
    • It isn’t clear whether there is a way to invoke GitHub APIs for a migration of this scale such that it wouldn’t violate GitHub API terms of use.

He also has an archiving proposal:

We would take the comments from an article on docs.microsoft.com and then convert them into a Markdown file. During this process, we would strip all user info (remember GDPR). The Markdown file would then be committed to a GitHub repo. Finally, at the bottom of the feedback section, next to the link that says "View on GitHub" we would add a second link that said something like "View Comment Archive". This link would connect you directly to the Markdown comment file for that page.

This sounds positive. At the same time, it is a mess that illustrates some of the disadvantages of a “best of breed” approach to solving technical problems. If Microsoft could use its own technology to host a documentation and commenting system, and a source code management and issue tracking system for that matter, this issue would not occur, and users would not need multiple accounts, causing the legal issues mentioned above.

Microsoft in fact used to use its own platform for all the above but decided to shift to using third-party solutions because they worked better. That seemed to be a good thing, improving user experience and productivity, but becomes a problem when what seems to be the best third-party option changes.

.net, development, software development, tech, Web

What the Blazor! After Silverlight, .NET in the browser reappears by another route

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Silverlight, Microsoft’s browser plug-in which included a cut-down .NET runtime, once seemed full of promise for developers looking for an end-to-end .NET solution, cross-platform on Windows and Mac, and with support for “out of browser” applications for a native-like experience.

Silverlight was killed by various factors, including the industry’s rejection of old-style browser plug-ins, and warring factions at Microsoft which resulted in Silverlight on Windows Phone, but not on Windows 8. The Windows 8 model won, with what became the Universal Windows Platform (UWP) in Windows 10, but this is quite a different thing with no cross-platform support. Or there is Xamarin which is cross-platform .NET, and one day perhaps Microsoft will figure out what to do about having both UWP and Xamarin.

Yesterday though Microsoft announced (though it was already known to those paying attention) Blazor, an experimental project for hosting the .NET Runtime in the browser via WebAssembly. The name derives from “Browser + Razor”, Razor being the syntax used by ASP.NET to combine HTML and C# in a web application. C# in Razor executes on the server, whereas in Blazor it executes on the client.

Blazor is enabled by work the Xamarin team has done to compile the Mono runtime to WebAssembly. Although this sounds like a relatively large download, the team is hoping that a combination of smart linking (to strip out unnecessary code in both applications and the runtime) with caching and HTTP compression will make this acceptable.

This post by Steve Sanderson is a good technical overview. Some key points:

– you can run applications either as interpreted .NET IL (intermediate language) or pre-compiled

– Blazor is an SPA (Single Page Application) framework with solutions for routing, state management, dependency injection, unit testing and more

– UI components use HTML and CSS

– There will be a browser API which you can call from C# code

– you will be able to interop with JavaScript libraries

– Microsoft will provide ASP.NET libraries that integrate with Blazor, but you can use Blazor with any server-side technology

What version of .NET will be supported? This is where it gets messy. Sanderson says Blazor will support .NET Standard 2.0 or higher, but not completely in the some functions will throw a PlatformNotSupported exception. The reason is that not all functions make sense in the context of a Blazor application.

Blazor sounds promising, if developers can get past the though the demo application on Azure currently gives me a 403 error. So there is this video from NDC Oslo instead.

The other question is whether Blazor has a future or will join Silverlight and other failed attempts to create a new application platform that works. Microsoft demands much patience from its .NET community.

.net, software development, tech

Which .NET framework for Windows: UWP, WPF or Windows Forms?

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Yes, mobile is the future of client applications, cross-platform is cool, web applications are amazing; but out there in the real world, there are still a ton of people who work all day with a Windows PC, and businesses that want PC applications in order to get their work done.

So when a business comes to you and says, we want a new Windows application to do this or that, and presuming they do not care about mobile or Macs or access over the internet but just want something that runs on their internal network, what framework do you choose?

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Let us even assume that they all run Windows 10 so that UWP (Universal Windows Platform) is a realistic option.

If you want to code in .NET (which is a great choice for a Windows-only application, and with the possibility of migrating code to cross-platform via Xamarin’s compiler later), then you have three obvious choices:

Windows Forms

This is the framework for Windows desktop applications that was introduced at the same time as .NET itself, back in 2002. Of course it has been revised many times since. There was a big update in 2006 with .NET 2.0. That said, Microsoft intended it to be replaced by Windows Presentation Foundation (WPF, see below), so it has not been a focus of attention. In 2014, High DPI support was improved, with .NET 4.5.2, reflecting the fact that this ancient framework is still widely used.

Windows Forms is a nice wrapper around the Windows API, and easy to use in that it uses essentially X Y layout. In other words, you can think of your form as a grid of pixels with the position of your controls determined at design time by its size and coordinates. This is great if you are designing and running on the same PC, but not so good when you deploy to other PCs with different display settings. It does kind-of scale if you follow certain rules, but successful scaling in a Windows Forms application is often difficult to achieve, so users may suffer chopped-off controls and text, or just ugly screens. Read this carefully if you use Windows Forms. And then read about High DPI support, which was improved again in .NET Framework 4.7.

If you are writing a database application, you can generate datasets by drag and drop from the Server Explorer in Visual Studio and bind them to controls. I am not a fan of this database framework, which quickly gets convoluted, but you do not have to use it. However the ability to bind list and grid controls to any kind of .NET collection is fantastically useful.

Why is Windows Forms still in use? It is partly legacy and the fact that it is easier to maintain and enhance an existing application than to start again. It is also because, scaling issues aside, Windows Forms is reliable, well supported by both built-in and third-party controls, and easy to learn.

Windows Presentation Foundation

This was Microsoft’s second go at a GUI framework for .NET and in many respects a great improvement. It was introduced with .NET Framework 3.0 in 2006, part of the Vista wave of technology. Unlike Windows Forms, it is based on the DirectX graphics API, so great for multimedia and special effects. Scaling is built-in and based on layout managers. The underlying presentation language is based on XAML, an XML language. As with Windows Forms, there is deep support for binding data to controls.

Why would you not always use WPF rather than Windows Forms? The main issue is that the time you save on figuring out scaling is more than consumed by the time you spend on design. WPF is a designer-centric framework. It will repay your efforts, but if you just want to slap a couple of grids and a few buttons on a form to get a working business application, Windows Forms remains tempting.

Universal Windows Platform

Both Windows Forms and WPF are old, and Microsoft is pointing developers towards its Universal Windows Platform (UWP) instead. UWP is an evolution of the new application platform introduced in Windows 8 in 2012. If WPF was all about scaling and multimedia, the Windows 8 modern app platform is about touch support and Store-based deployment. The application model was also service based, the idea being that your app consumes services published over the internet. Until the Windows 10 Fall Creators Update, you could not use the .NET SQLClient to connect directly to a SQL Server database (you can now). The app platform became UWP with the launch of Windows 10 in 2015. UWP can use XAML for layout design, but it is not compatible with WPF.

Personally I have mixed feelings about UWP. Unfortunately it has suffered from Microsoft’s ever-changing development strategy. The Windows 8 app platform made sense to me as a way of bringing Windows into the tablet era and enabling applications that were more secure and more easily deployed, even if it tended to result in applications that were blocky and ugly. Microsoft then changed its mind about full-screen touch applications and came up with the UWP for Windows 10, where applications again run in a window, but with a new selling point: you could run your application on Windows Phone as well as desktop. Then the company canned Windows Phone, before UWP had properly launched, in effect deleting the “Universal” part of the platform.

UWP still offers Store delivery and isolation from other applications, better for security and stability. However there are a few things against it. First, users require Windows 10. Second, like WPF it is a designer-centric platform and not so good for running up quick business applications. Third, UWP apps behave differently from standard desktop applications, sometimes not in a good way.

I was using Microsoft’s bundled Photos application recently. I work a lot with images so this often pops up, as the default image viewer on Windows 10. I was not stressing it, but it crashed which, as is typical for a UWP app, means it just disappeared without any message or warning.

UWP will be three years old this summer, but I am not convinced that the platform is quite there yet. I find it hard to think of UWP apps that I love. The apps I know best are the built-in ones, Mail, Photos, Groove Music, Calculator, and I do not love any of them. Paint 3D is amazing but not my thing.

At the same time I do see the merits of UWP versus traditional Windows application deployment. The existence of the Desktop Bridge (formerly Project Centennial) means you can get many of those benefits while still using WPF or Windows Forms.

Closing thoughts

Perhaps something like Power Apps will render this discussion irrelevant before long. There are also other options for the desktop, such as Xamarin Forms if you still want to use .NET, or Electron for using web technologies for desktop applications.

Still, while it may seem surprising, even in 2018 I can think of reasons why you might use any of the above frameworks, even Windows Forms, for a business app targeting Windows.

.net, development, microsoft, Web

Generating code for simple SQL Server data access without Entity Framework, works with .NET Core

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I realise that Microsoft’s Entity Framework is the most common approach for data access in the .NET world, but I have also always had good results from a simple manual approach using DbConnection, DbCommand and DataReader objects, and like the fact that I can see and control exactly what SQL gets executed. If you prefer using Entity Framework or another abstraction that is fine and please stop reading now!

One snag with this more manual approach is that you have to write tedious code building SQL statements. I figured that someone must have written a utility application to generate this code but could not find one quickly so I did my own. It supports both C# and Visual Basic. The utility connects to a database and lets you generate a class for each table along with code for retrieving and saving these objects, ready for modification. Here you can see a generated class:

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and here is an example of the generated data access code:

image

This is NOT complete code (otherwise I would be perilously close to writing my own ORM) but simply automates creating SQL parameters and SQL statements.

One of my thoughts was that this code should work well with .NET core. The SQLClient implements the required classes. Here is my code for retrieving an author object, mostly generated by my utility:

public static ClsAuthor GetAuthor(string authorID)
        {
            SqlConnection conn = new SqlConnection(ConnectString);
            SqlCommand cmd = new SqlCommand();
            SqlDataReader dr;
            ClsAuthor TheAuthor = new ClsAuthor();
            try
            {
                cmd.CommandText = "Select * from Authors where au_id = @auid";
                cmd.Parameters.Add("@auid", SqlDbType.Char);
                cmd.Parameters[0].Value = authorID;
                cmd.Connection = conn;
                cmd.Connection.Open();

                dr = cmd.ExecuteReader();

            if (dr.Read()) {

                    //Get Function
                    TheAuthor.Auid = GetSafeDbString(dr, "au_id");
                    TheAuthor.Aulname = GetSafeDbString(dr, "au_lname");
                    TheAuthor.Aufname = GetSafeDbString(dr, "au_fname");
                    TheAuthor.Phone = GetSafeDbString(dr, "phone");
                    TheAuthor.Address = GetSafeDbString(dr, "address");
                    TheAuthor.City = GetSafeDbString(dr, "city");
                    TheAuthor.State = GetSafeDbString(dr, "state");
                    TheAuthor.Zip = GetSafeDbString(dr, "zip");
                    TheAuthor.Contract = GetSafeDbBool(dr, "contract");
                }
            }
            finally
            {
                conn.Close();
                conn.Dispose();
            }

            return TheAuthor;
        }

Everything worked perfectly and I soon had a table showing the authors, using ASP.NET MVC.

In order to verify that it really does work with .NET Core I moved the project to Visual Studio Mac and ran it there:

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I may be unusual; but I am reassured that I have a relatively painless way to write a database application for .NET Core without using Entity Framework.

.net, microsoft, software development, visual studio, windows

Microsoft updates the .NET stack with .NET Core 2.0 and updated Visual Studio. Should you use it?

2 Comments

Microsoft has released .NET Core 2.0, a major update to its open source, cross-platform version of the .NET runtime and C# language.

New features include implementation of .NET Standard 2.0 (a way of targeting code to run under multiple .NET platforms), new platform support including Debian Stretch, macOS High Sierra and Suse Linux Enterprise Server 12 SP2. There is preview support for both Linux and Windows on ARM32.

.NET Core 2.0 now supports Visual Basic as well as C# and F#. The version of C# has been bumped to 7.1, including async Main method support, inferred tuple names and default expressions.

Microsoft has also released Visual Studio 2017 15.3, which is required if you want to use .NET Core 2.0. New Visual Studio features include Azure Stack support, C’# 7.1 support, .NET Framework 4.7 support, and other new features and fixes.

I updated Visual Studio and downloaded the new .NET Core 2.0 SDK and was soon up and running.

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Note the statement about “This product collects usage data” of which more below.

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The sample ASP.NET MVC application worked first time.

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How is .NET Core doing? The whole .NET picture is desperately confusing and I get the impression that most .NET developers, while they may have paid some attention to what is happening, have concluded that the safe path is to continue with the Window-only .NET Framework.

At the same time, .NET Core is strategically important to Microsoft. Cross-platform support means that C# has a life on the Mac and on Linux, which is vital to its health considering the popularity of the Mac amongst developers, and of Linux as a deployment platform for web applications. Visual Studio for Mac has also been updated and supports .NET Core 2.0 in the new version.

Another key piece is the container trend. .NET Core is ideal for container deployment, and the only version of .NET supported in Windows Nano Server. If you want to embrace microservices running in containers, while still developing with C#, .NET Core and Nano Server is the optimum solution.

Why not use .NET Core, especially since it is faster than ASP.NET? In these comparisons, .NET Core comes out as substantially faster than .NET Framework for various algorithms – 600 times faster in one case.

The main issue is compatibility. .NET Core is a subset of the .NET Framework, and being a relative newcomer, it lacks the same level of third-party support.

Another factor is that there is no support for desktop applications, though some solutions have been devised. Microsoft does have a cross-platform GUI story, in Xamarin Forms, which is now in preview for macOS alongside iOS, Android, Windows and Tizen. If Xamarin used .NET Core that would be a great solution, but it does not (though it does support .NET Standard 2.0).

One of the pieces that most concerns developers is data access. If you use .NET Core you are strongly guided towards Entity Framework Core, a fork of Microsoft’s ORM (Object-Relational Mapping) framework. Someone asked on this page, is EF Core usable? Here’s an answer from one user (11 days ago):

Answering 4 months later but people should know: Definitely not, it is still not usable unless you are doing something very trivial and/or have very small DB.
I don’t understand how it is possible for MS to ship it, act like it’s OK and sparsely here and there provide shallow information about its limitations like in this article without warning clearly and explicitly about the serious issues this “v1 product” has.

Someone may jump in and say no, it is fine; but there are undoubtedly missing pieces and I would suggest caution.

You can also access data using the Connection/Command/DataReader approach which avoids EF, and although this is more work, this is what I would be inclined to do personally since you get the best performance and flexibility. Here is an example for SQL Server.

Who is using .NET Core? Controversially, Microsoft gathers telemetry from your use of the command-line tools though you can opt out by setting an environment variable. This means we have some data on .NET Core usage, though unfortunately it excludes Visual Studio usage. I downloaded the most recent dataset and imported it into a database. Here are the figures for OS family:

Total rows 5,036,981
Windows 3,841,922 (76.27%)
Linux 887,750 (17.62%)
Mac 307,309 (6.1%)

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Given that this excludes Visual Studio users, who are also on Windows, we can conclude that the great majority of .NET Core developers use Windows, and only a tiny minority Mac (I do not know if Visual Studio for Mac usage is included). This is evidence that .NET Core has so far failed in its goal of persuading Mac-using developers to adopt .NET. It does show interest in deploying .NET applications to Linux, which is an obvious win in licensing costs as well as performance.

I would be interested in comments from developers on whether or not they use .NET Core and why.