启用.NET Native工具链后Windows Store App登录异常及Task.cs找不到问题

Let me walk you through fixing this frustrating issue—this is a common hiccup when using .Net Native with apps that rely on P/Invoke calls or third-party auth libraries like AAD's SDK.

Root Cause #

When you enable the Compile with .Net Native tool chain option, the compiler does aggressive optimizations to shrink app size and boost performance. By default, it strips out methods/types it thinks are unused. The error Unresolved P/Invoke method 'InternetSetOption!wininet.dll' means the compiler removed or failed to resolve this P/Invoke call, which the AAD auth library uses under the hood. The "Task.cs not found" message is a secondary side effect: .Net Native optimizes the mscorlib assembly so much that debug symbols for Task.cs aren't available, but this isn't the actual blocking issue.

Step-by-Step Fixes #

1. Check Build Warnings First
   The exception explicitly tells you to look at build warnings—head to Visual Studio's Output window (select "Build" from the dropdown menu) and search for entries related to InternetSetOption or wininet.dll. These warnings will give you exact details on why the method isn't being resolved, which helps target your fix.

2. Add a Runtime Directives (rd.xml) File
   .Net Native needs explicit instructions to preserve certain methods, types, or native libraries. Here's how to set this up:

   • Right-click your Windows Store project > Add > New Item > Search for "Runtime Directives File" and add it (name it Default.rd.xml if not auto-named).
   • Update the file with this content to preserve the required P/Invoke method and AAD-related code:

     <Directives xmlns="http://schemas.microsoft.com/netfx/2013/01/metadata">
       <Application>
         <!-- Preserve the InternetSetOption method from wininet.dll -->
         <NativeLibrary Name="wininet.dll">
           <EntryPoint Name="InternetSetOption" />
         </NativeLibrary>
         <!-- Preserve all code in your app's assembly (replace with your actual assembly name) -->
         <Assembly Name="YourAppAssemblyName" Dynamic="Required All"/>
         <!-- Preserve the AAD authentication library (use the correct NuGet package name) -->
         <Assembly Name="Microsoft.Identity.Client" Dynamic="Required All"/>
       </Application>
     </Directives>
     

   • Swap YourAppAssemblyName with your project's assembly name (find this in project properties under the "Application" tab).

3. Update Your AAD Authentication Library
   Older versions of MSAL (Microsoft Authentication Library) or ADAL (Azure AD Authentication Library) often have compatibility gaps with .Net Native. Upgrade to the latest stable version of MSAL (it's the recommended replacement for ADAL now) via NuGet—this alone can resolve many native compilation issues.

4. Clean and Rebuild Your Solution
   Cached build artifacts can cause weird, hard-to-track issues. Do a full clean and rebuild:

   • Go to Build > Clean Solution
   • Then Build > Rebuild Solution
   • Test the app again with the .Net Native tool chain enabled.

5. Ignore the "Task.cs Not Found" Debug Message
   This is purely a debug symbol limitation—since .Net Native optimizes mscorlib, the debug symbols for Task.cs aren't included in the compiled output. Once you fix the P/Invoke error, this message won't stop your app from running. If you need to debug Task-related code, just disable .Net Native for debug builds (keep it enabled only for release builds where performance matters).

内容的提问来源于stack exchange，提问作者Muhammad Khurram Bhatti