[Problem/Bug]: Cannot change thread mode after it is set.

[shishiraltysys]

What happened?

When I am using multiple Window application and I want to open a new form of XYZ application, from ABC application, I am using main and ui thread approach, but when i am trying to access XYZ application form that basically uses WebView2 controls, I get an error when i call below code

try
{
var environment = await CoreWebView2Environment.CreateAsync(null, null);

webMessage.CoreWebView2InitializationCompleted += WebBrowser_CoreWebView2InitializationCompleted;

await webMessage.EnsureCoreWebView2Async(environment);

}

Error detail
************** Exception Text **************
System.Runtime.InteropServices.COMException (0x80010106): Cannot change thread mode after it is set. (0x80010106 (RPC_E_CHANGED_MODE))
at System.Runtime.InteropServices.Marshal.ThrowExceptionForHR(Int32 errorCode)
at Microsoft.Web.WebView2.Core.CoreWebView2Environment.CreateAsync(String browserExecutableFolder, String userDataFolder, CoreWebView2EnvironmentOptions options)
at Microsoft.Web.WebView2.WinForms.WebView2.InitCoreWebView2Async(CoreWebView2Environment environment, CoreWebView2ControllerOptions controllerOptions)
at UTIL.App.AlertItemForm.InitializeAsync() in C:\FDB\DEV\UTIL\src\App\ItemForm.cs:line 383
at System.Threading.Tasks.Task.<>c.b__128_0(Object state)
at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)

Importance

Blocking. My app's basic functions are not working due to this issue.

Runtime Channel

Stable release (WebView2 Runtime)

Runtime Version

1.0.2277.86

SDK Version

1.0.2277.86

Framework

Winforms

Operating System

Windows 11

OS Version

No response

Repro steps

Run the code and getting above issue

Repros in Edge Browser

No

Regression

No, this never worked

Last working version (if regression)

1.0.2277.86

[shishiraltysys]

@joshholmes @quietfanatic @oggy22 @yildirimcagri-msft
Please help me

[LiangTheDev]

WebView2 by design requires running from STA: https://learn.microsoft.com/en-us/microsoft-edge/webview2/concepts/threading-model. Try to see whether there is any code calling CoInitializeEx with COINIT_MULTITHREADED. Try change that to be COINIT_APARTMENTTHREADED.