AddHostObjectToScript() results in exception

[ray007]

Description
I'm calling

CoreWebView2.AddHostObjectToScript("name", new Bridge(view));

and get an exception: System.ArgumentException: "Value does not fall within the expected range."

Stacktrace into webview:

   at Microsoft.Web.WebView2.Core.Raw.ICoreWebView2.AddHostObjectToScript(String name, Object& object)
   at Microsoft.Web.WebView2.Core.CoreWebView2.AddHostObjectToScript(String name, Object rawObject)
   at Out.Company.Presenter.<InitializeWebviewAsync>d__16.MoveNext() in C:\rtc-sandbox\...\Presenter.cs:line 290

Version
SDK: 1.0.1901.177
Runtime: 115.0.1901.183
Framework: WPF with .NET 4.7.2
OS: Win10

Regression
Was this working before but has regressed?
Unknown since I had no old version.

Additional context
The Bridge class is defined with attributes

	[ClassInterface(ClassInterfaceType.AutoDual)]
	[ComVisible(true)]

is there something else I need to do take make the Bridge usable as host object?

[sq800]

I had this problem too, but I finally solved it, this is my problem

var libraryHelper = new LibraryHelper();
webView.CoreWebView2.AddHostObjectToScript("LibraryHelper", libraryHelper); //System.ArgumentException:“Value does not fall within the expected range.”

Version
SDK: 1.0.1901.177
Runtime: 116.0.1938.162
Framework: WPF with .NET 6
OS: Win11

I found the cause of the exception. My "LibraryHelper" class forgot to add modifier. After adding the "Public" modifier, everything was normal.

Modify

To

[ray007]

@sq800 Thanks for trying, but unfortunately, that didn't change anything for me.

[ray007]

Hmm, some more experimenting and upgrading Microsoft.Web.WebView2 to version 1.0.2065-prerelease, things do work a bit better now.
I now do not get an exception on calling AddHostObjectToScript() anymore, but in many cases when invoking the methods of the host object.

There seems to be a problem with optional parameters. They get filled in correctly, but I get a System.Runtime.InteropServices.COMException on (or after) the method return when I do not provide all of them in the call:

   at Microsoft.Web.WebView2.Core.CoreWebView2PrivateHostObjectHelper.RawHelper.IsAsyncMethod(Object& rawObject, String methodName, Int32 parameterCount)

But the value still gets returned to the webview.

At least simple values.
I have yet to find a way to hava javascript objects as parameters or result of a method call.
Other than JSON serialize/deserialize.
I tried with Hashtable and Dictionary<String, Object>, but no luck so far. Is there a type for that?

[ray007]

Edit: some mistakes on my part yesterday, other than objects as parameters or call-result, things seem to be working now.

[victorhuangwq]

@ray007 I would close this issue if it's not an issue?

[ray007]

Did I miss something about parameters of type Object?
But all right, I'll close it.

[jMWCQQQ1]

Hmm, some more experimenting and upgrading Microsoft.Web.WebView2 to version 1.0.2065-prerelease, things do work a bit better now. I now do not get an exception on calling AddHostObjectToScript() anymore, but in many cases when invoking the methods of the host object.

There seems to be a problem with optional parameters. They get filled in correctly, but I get a System.Runtime.InteropServices.COMException on (or after) the method return when I do not provide all of them in the call:

   at Microsoft.Web.WebView2.Core.CoreWebView2PrivateHostObjectHelper.RawHelper.IsAsyncMethod(Object& rawObject, String methodName, Int32 parameterCount)

But the value still gets returned to the webview.

At least simple values. I have yet to find a way to hava javascript objects as parameters or result of a method call. Other than JSON serialize/deserialize. I tried with Hashtable and Dictionary<String, Object>, but no luck so far. Is there a type for that?

i have a same exception. i don't know why the IsAsyncMethod called. How did you solve this exception

[ray007]

@jMWCQQQ1 make sure it's declard as public class and I have some more lines before the class declaration:

#pragma warning disable CS0618
	[ClassInterface(ClassInterfaceType.AutoDual)]
#pragma warning restore CS0618
	[ComVisible(true)]

I think that's all I did to make it work back then...

[jMWCQQQ1]

@jMWCQQQ1 make sure it's declard as public class and I have some more lines before the class declaration:

#pragma warning disable CS0618
	[ClassInterface(ClassInterfaceType.AutoDual)]
#pragma warning restore CS0618
	[ComVisible(true)]

I think that's all I did to make it work back then...

I have already done these same things, but still report errors。but thanks