C# class libraries DLL to C++ application with UWP

Question

Hi,

I'm currently searching for a solution that would allow me to use my C#-UWP-based DLL (inside containing two classes) and using the methods contained within in another UWP-based C++ application. After an exhaustive search, I'm seeing the only possible method is to expose the DLL as a COM-type object(?) and reference it in my C++ project, however, many of the examples are based on .NET approach.

I haven't been successful in finding any clear example on how to do this. And based on what I've read, it also appears this may not be possible because its UWP-based(?). I would appreciate if someone might be able to provide an explanation or direction to where or how I could tackle this problem? Thank you.

Answer 1

Hello,

Welcome to Microsoft Q&A!

You couldn't directly use a C# class library in your C++ application. You need to use a C# Windows Runtime Component instead. And you will need to do some extra steps to make sure the C# component is compiled correctly with the C++ application.

Here are the steps to create a simple test sample:

1. Create a new "Blank App (Universal Windows - C++/CX)"
2. Create a new "Windows Runtime Component (Universal Windows)", C#, Called TestWinRTLib in the solution.
3. Add a simple test method in the Class1.cs:

    public static string GetName()  
           {  
               return "David";  
           }  
   

4. Add referece of the TestWinRTLib in the C++ project. And call the method like this:

   using namespace TestWinRTLib;  
   
   void TestCXProJECT::MainPage::Button_Click(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)  
   {  
   	auto str = Class1::GetName();  
   }  
   

5. Right click on the C++/CX project, choose Manage NuGet Packages.
6. Search for Microsoft.Net.Native.Compiler, and install it
7. Right-click the C++/CX project -> Unload Project -> Edit .vcxproj, add following properties to the PropertyGroup. Remember to replace the 2.2.3 version above with the version of Microsoft.Net.Native.Compiler nuget package you installed

   <PropertyGroup Label="Globals">  
        <-- other properties -->  
   
       <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>  
       <DotNetNativeVersion>2.2.3</DotNetNativeVersion>  
    </PropertyGroup>  
   

8. Reload the C++/CX project first, then right click the Solution, choose Restore NuGet Packages
9. Run the C++ app and click the button, you could get string from the C# Component.

The result looks like this:

You could refer these this as well: Could not load file or assembly.

Thank you.

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