JavascriptObjectRepository seems can not effect UI thread?

[tp1415926535]

I followed the "How do you expose a .NET class to JavaScript" and achieved it, but when I change UI in class method, there will be some error in console when call it, like this:
C# code:

    browser.JavascriptObjectRepository.Register("boundAsync", new BoundObject(this), true, BindingOptions.DefaultBinder);

    public class BoundObject
    { 
        private MainWindow mainWindow;
        public BoundObject(MainWindow MainWindow)
        {
            mainWindow = MainWindow;
        }
        public int Add(int a, int b)
        {                
            mainWindow.Title = "new Title";
            return a + b;
        }
    }

JS code:

    (async function()
    {
        await CefSharp.BindObjectAsync("boundAsync");
        boundAsync.add(16, 2);
    })();

error:

InvalidOperationException"(located in WindowsBase.dll)
TargetInvocationException"(located in mscorlib.dll)
InvalidOperationException"(located in CefSharp.dll)
[0822/003331.413:INFO:CONSOLE(0)] "Uncaught (in promise) System.InvalidOperationException: Could not execute method: add(16, 2) ---> System.Reflection.TargetInvocationException:XXXXXXX---> System.InvalidOperationException: XXXXX
System.Windows.Threading.Dispatcher.VerifyAccess()
System.Windows.Window.set_Title(String value)
....

so is there a way like webbrowser.ObjectForScripting can effect to the window UI ?

[ukandrewc]

Assuming boundObject was created on your UI thread, you need to invoke mainWindow.Title because the call into boundObject.add is made on the CEF UI thread.

PS: The stacktrace tells you that because it failed on Dispatcher.VerifyAccess(), which checks that you are calling from the same thread.

[amaitland]

because the call into boundObject.add is made on the CEF UI thread.

Methods are actually executed on the thread pool.

so is there a way like webbrowser.ObjectForScripting can effect to the window UI ?

@tp1415926535 you can use the dispatcher to access the UI thread. Your MainWindow will have a Dispatcher property.

https://docs.microsoft.com/en-us/dotnet/api/system.windows.threading.dispatcher.invokeasync?view=net-5.0#System_Windows_Threading_Dispatcher_InvokeAsync_System_Action_

[tp1415926535]

@tp1415926535 you can use the dispatcher to access the UI thread. Your MainWindow will have a Dispatcher property.

https://docs.microsoft.com/en-us/dotnet/api/system.windows.threading.dispatcher.invokeasync?view=net-5.0#System_Windows_Threading_Dispatcher_InvokeAsync_System_Action_

well... I make it after add a Invoke method there :

        public int Add(int a, int b)
        {
            mainWindow.Dispatcher.Invoke(new Action(() =>
            {
                mainWindow.Title = "new Title";
            }));
            return a + b;
        }

it works, thanks.

[amaitland]

Use InvokeAsync instead of Invoke.

[ukandrewc]

Methods are actually executed on the thread pool.

Aha, worth knowing ;-)

[tp1415926535]

使用 InvokeAsync 而不是 Invoke。

Oh, good idea.