Last week I wanted to add a Wiki to a .Net WinForms project I was working on and surprisingly didn’t seem to find an obvious and simple candidate. With (a lot) of help from ChatGPT I found two great resources which I could use to make one for myself:
Refer to the Markdown guide for more information on Markdown formatting.
Most of the code and effort was done by GPT4.1 via Copilot in Visual Studio 2022, using Agent mode.
Flow-coding
Flow-coding sits somewhere between conventional coding and vibe-coding. Unlike vibe-coding, which leans heavily on prompt engineering, flow-coding keeps the human deeply engaged in shaping the code while AI tools like Copilot act as an active partner. It’s an ongoing conversation where ideas and code evolve together.
TLDR; set CausesValidation to true on a ribbon bar button to make sure any controls that support validation, such as property grids, have their changes committed and validated before moving focus to the button.
I recently had a problem trying to verify data on a property grid – any changes I had just made, where the cursor was still active on the grid editor, were not committed when I clicked a ribbon bar button. For example, when my application starts it looks like this:
And when I click ‘Display person’ I get a message box:
However, if I change the ‘Age’ property and click the ‘Display person’ button without first hitting the enter key, I see this:
The DevExpress button click does not result in the changes being noticed before displaying the message box because the CausesValidation property is false:
Note that the built-in .Net Framework button has this property set to true by default.
Changing the property to true causes the property grid’s validation to be performed which includes attempting to commit any live changes to the underlying object, the Person instance.
And adding a message box to the property grid’s validating event makes the change and sequence of events more visible:
First:
Then:
Written this post because I figured this out about 2 years ago and today forgot everything !
These are the steps I used to compile OpenCV V4.6.0 from the source code using Visual Studio 2022.
CMake is used to generate a custom Visual Studio solution
The latest CMake didn’t work (see below) so I used the previous version
My end-goal was a set of static libraries that could be used from a C++/CLI project
This workflow assumes that VS2022 is already installed, including at least the C++ workload:
CMake
Install CMake V3.24.3. This will be used to generate a custom Visual Studio 2022 solution which can then be used to build the OpenCV libraries.
Note: at the time of writing the latest version of CMake, V3.25.0, has an issue which makes it unusable for generating the OpenCV projects. Other people also talking about this on stackoverflow.
A second build procedure is required to generate the OpenCV distribution, required by any apps that want to use OpenCV. Expand the CMakeTargets folder in the solution explorer and build the INSTALL project.
In Windows Explorer you should now have a [new] Install folder:
\Downloads\opencv-4.6-build\install
This should include all the key headers and static library files required for building a C++/CLI or similar application or library.
Generate the release files by repeating the above procedure (using the Release|x64 configuration).
Final note
I’ve never, once, managed to just grab OpenCV source, configure and build, and then consume, without many hours of hacking about trying to figure why something doesn’t compile.
Using the OpenCV_World option can be worth a try if there are problems – this library (or DLL) contains most of the libraries packed into a single library.
I have a .Net 5 WinForms Control library (Windows 10, Visual Studio 2019) and want to add some unit tests for the non-UI classes. After adding an xUnit project and referencing my library I get this error:
error NU1201: Project WinFormsControlLibrary1 is not compatible with net5.0 (.NETCoreApp,Version=v5.0). Project WinFormsControlLibrary1 supports: net5.0-windows7.0 (.NETCoreApp,Version=v5.0)
This happens because the WinForms library targets .Net 5 Windows, which is more specific than general .Net 5.
I fix this by double-clicking the unit test project (in solution explorer) and editing the target framework from:
<TargetFramework>net5.0</TargetFramework>
To:
<TargetFramework>net5.0-windows</TargetFramework>
Then, close my project and Visual Studio, and re-open it. (This gives VS2019 a chance to figure what’s going on!) Now the project compiles and I can create and run unit tests.
Note: The Target Framework, shown in the project properties page, is now blank:
So I select .Net 5, close the page, and look again at the project JSON file – now the target framework has changed to:
After much struggle, learning and googling, I’ve finally made my own small library that provides a simple C# code editor and a bunch of simple C# scripting utilities.
A few years ago I wrote a simple Scintilla.net-based code editor and, with the Microsoft CSharp scripting library, managed to let my apps provide code editing and run-time C# script execution. The code was scrappy and without intellisense also difficult to use for non-trivial scripts.
Then I found the RoslynPad project, which uses AvalonEdit for the underlying text editor to provide a WPF C# scripting editor. As well as a stand-alone application the text editor is also available via NuGet. Since I work almost entirely with WinForms, rather than WPF, I wanted an easy-to-use drag-and-drop widget to provide code editing. So I wrote CDS.CSharpScripting.
As well as the code editor there are classes for script compilation and execution, including EasyScript, a class that allows for one-line compilation and execution. The compiler utilities provide access to the compilation results such as errors and warning.
Example 1:
EasyScript<object>.Go("Console.WriteLine(\"Hello world, from the script!\");");
Output:
Hello world, from the script!
There’s still lots to do on the project including mode demos, getting code actions to work – they actual actions do already work but the menu text is broken.
If you need something with more power than my simple code editor wrapper then the RoslynPad project is available on GitHub. There are also countless demos showing how to use Microsoft’s C# scripting classes directly. But if you just need a quick code editor and the ability to compile and run code at runtime, capture script return values and share data between the host app and the script, then this is not a bad place to start.
Some of my projects always build, whereas others just say they’re already up-to-date.
I’ve finally got something that’s actually helping me isolate the problems, and it’s related to bringing in packages via NuGet that bring in lots of other dependencies.
The first step is to change the MSBuild output from Minimal to Diagnostics:
Run the build once just in case anything really has changed.
Build the project and look at the top of the diagnostics in the output window. As an example, I have this
1>Project 'AmberOptix.AOX3.Scripting' is not up to date. CopyLocal reference 'C:\dev\Projects\Amber\AOX3\AmberOptix.AOX3.Scripting\bin\Debug\System.Diagnostics.StackTrace.dll' is missing from output location.
Next I remove this assembly (System.Diagnostics.StackTrace.dll) from my packages.config file and the references. Then I build again and repeat the process until it eventually says that everything is up-to-date.
For some of the ‘missing’ assemblies I can guess that several others may also not be required. For example I deleted 3 System.Net.XXX packages and references when System.Net.Http was reported as missing.
As a guideline I had to remove over 20 packages and references from my scripting library to get this working.
An alternative to this manual approach of deleting one at a time is to delete all packages and references, then go through a cycle of adding back NuGet packages and normal assembly references as required.
I’m still sure there must be a better and safer way to do this! I think JetBrains’ ReSharper has tools but haven’t had a chance to trial yet.
‘Type here to search’ suddenly stopped this morning on all of my virtual machines. Presumed this was a Parallels problem, however it’s related to Bing and lots of people have this problem…
Windows Search has stopped working. The culprit is Bing search integration. Disable Bing search with this guide: https://t.co/3tfGH22nWI
It took a few attempts to get a compatible Python and OpenCV library running under Visual Studio Code on macOS Catalina using a virtual environment. I made a video to show how I got this going – this post just adds some more details.
There is also an excellent tutorial from Microsoft:
Visual Studio Code running on a virtual machine may have problems rendering the interface. This seems to be related to the underlying Electron framework and GPU acceleration. I made a quick video to show how I got around this:
Fix rendering problems for Visual Studio Code running on a virtual machine
Install Python 3.7.5
A virgin Mac comes with Python 2.7 installed – this is not recommended and V3.7.5 works with OpenCV4 on a Mac. V3.8 does not work at the time of writing (although since I started writing this post it looks like it now does). Download the installer from the main python website by selecting Downloads, Mac OS X, and then selecting the 64-bit installer:
Run the installer – I used all default settings.
Install Visual Studio Code
Download the installer from Visual Studio Code and immediately move the downloaded file to the Applications folder. (This is the actual application, not an installer). Try to run once – macOS will refuse due to security:
Close the message, open System Preferences, and select the Security and Privacy settings. Then select “Open Anyway” to allow VSC.
Visual Studio Code should now start:
Configure Python
Open a folder by selecting Open folder and then add a new file. Save the file using the .py extension:
Visual Studio Code immediately offers to install the Python extension, select Install:
On a virgin Mac there will now be a prompt to install command line developer tools, so click Install if prompted and allow the installation to complete before returning to Visual Studio Code.
The status bar will show the selected interpret if everything has gone well:
Install the linter (pylint): this helps analyse the code for bugs and style issues. It also might not work first time but we can fix shortly…
If the terminal window suggests upgrading pip, the Python package manager, then go for it by running the following in the terminal window:
python3 -m pip install --upgrade pip
Make a virtual environment
A virtual environment is a self-contained directory tree that contains a Python installation for a particular version of Python
opencv-utils (0.0.2) – OpenCV Utilities ctypes-opencv (0.8.0) – ctypes-opencv – A Python wrapper for OpenCV using ctypes opencv-wrapper (0.2.3) – A Python wrapper for OpenCV. opencv-cython (0.4) – An alternative OpenCV wrapper dajngo-opencv (0.3) – Django Opencv integratio opencv-python (4.1.2.30) – Wrapper package for OpenCV python bindings
For this test I’m using opencv-python. The details on version 4.1.2.30 can be found on the Python Package Index site. Interestingly this version was only released a few hours ago and says it supports Python 3.8 😬 I guess I’ll try this on a virtual machine first to check it’s all ok!
Install OpenCV using pip:
python3 -m pip install opencv-python
Write some code and fix the linter
First test: import the OpenCV module and print the library version.
import cv2
print('Using OpenCV version {0}'.format(cv2.__version__))
After running this output is shown in the terminal:
But – there’s a problem. In the editor the linter is suggesting that cv2 is not a known module:
This has been seen before on the pylint GitHub issues page. For me, the solution is to edit the .vscode settings. Using ⇧⌘E (shift+command+E) to view the explorer page, expand the .vscode file and click settings.json:
Add a comma to the end of the line of the existing setting, then add the following new setting:
Tested with Parallels Desktop 15 Pro Edition on macOS Catalina.
Problem 1: using Visual Studio or notepad++ or any similar multi-document application in Windows 10 on a Mac using Parallels, ⌘W (Command+W) maps to Alt+F4. This means To close just an editor page you have to revert to the original Windows shortcut of Control+F4 which is a minor pain on a Mac with the Touch Bar instead of function keys.
Solution 1: change the Parallels preferences to remap ⌘W to Ctrl+F4. ⌘Q will still close an application but ⌘W will now close an internal editor window; this is the same behaviour used in Safari to close the whole application (⌘Q) or close just one page (⌘W).
Problem 2: Control+Tab and Shift+Control+Tab don’t switch between editor windows.
Solution 2: a recent update to Parallels resulted in these shortcuts being used for Parallels tab switching. They don’t get passed on to the VM. Just unchecking these shortcuts fixes the problem.
Short story: writing a unit test for an image processing function, I had the following key parameters for each test:
enum Algorithm { A, B, C };
enum ImageFormat { Gray, Color };
enum ImageSize { Small, Medium, Large };
I wrote a core test function that worked on just one combination of the 3 parameters. E.g.
void Test(
Algorithm algorithm,
ImageFormat imageFormat,
ImageSize imageSize)
{
Console.WriteLine($"Testing algorithm {algorithm} for " +
{imageFormat} image with {imageSize} size");
// the test...
}
Next, I wrote a utility to make iterating the values of an enumeration a little easier.. still not sure why this isn’t part of .Net yet:
class EnumHelper<T>
{
static public T[] Values
{
get { return (T[])Enum.GetValues(typeof(T)); }
}
}
Then, I wrote the nested loops that built each combination and sent them for testing:
void TestAllV1()
{
foreach (var algorithm in EnumHelper<Algorithm>.Values)
{
foreach (var imageFormat in EnumHelper<ImageFormat>.Values)
{
foreach (var imageSize in EnumHelper<ImageSize>.Values)
{
Test(algorithm, imageFormat, imageSize);
}
}
}
}
Now there’s nothing really wrong with the above, but it looked like something that should be able to be written more simply. So I came up with this:
void TestAllV2()
{
var tests =
from algorithm in EnumHelper<Algorithm>.Values
from imageFormat in EnumHelper<ImageFormat>.Values
from imageSize in EnumHelper<ImageSize>.Values
select (algorithm, imageFormat, imageSize);
foreach (var test in tests)
{
Test(test.algorithm, test.imageFormat, test.imageSize);
}
}
The use of the from clause seems better, mainly due to the reduced level of nesting. The Visual Studio 2019 code analysis metrics are interesting:
Member
MI
CycC
ClsC
TestAllV1()
76
4
7
TestAllV2()
69
2
18
Where:
MI: Maintainability Index
CycC: Cyclomatic Complexity
ClsC: Class coupling
So the foreach approach is (allegedly!) more maintainable, while the from clause method has a lower cyclomatic complexity. This latter metric reinforces the idea that this is slightly simpler than the foreach technique.
It’s also quite easy to add specific filtering inside the tests generator. For example, to quickly stop testing the B algorithm:
var tests =
from algorithm in EnumHelper<Algorithm>.Values
where algorithm != Algorithm.B
from imageFormat in EnumHelper<ImageFormat>.Values
from imageSize in EnumHelper<ImageSize>.Values
select (algorithm, imageFormat, imageSize);
Food for thought 🙂
Edit: actually found another way to do this using the Linq SelectMany method, but I’m not keen on this:
void TestAllV3()
{
var tests =
EnumHelper<Algorithm>.Values.SelectMany(
algorithm => EnumHelper<ImageFormat>.Values.SelectMany(
imageFormat => EnumHelper<ImageSize>.Values.Select(
imageSize => (algorithm, imageFormat, imageSize))));
foreach(var test in tests)
{
Test(test.algorithm, test.imageFormat, test.imageSize);
}
}
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