How to update gui in c# wpf from asynchronous method callback

问题

I've search on stackoverflow and also in net and I couldn't find solution to my problem.

I read from a stream in async way. I want callback to update gui

[STAThread]
    private void ClientLoggedCallback(IAsyncResult res)
    {
        try
        {
            MailClient.Helpers.Client.getInstance().client.GetStream().EndWrite(res);
            MailClient.Helpers.Client.getInstance().asyncRecieveEncryptedProtocolMessage(new AsyncCallback(LoginInfo_recieved));
        }
        catch { }
    }
    [STAThread]
    private void LoginInfo_recieved(IAsyncResult res)
    {
        try
        {
            MailClient.Helpers.Client.getInstance().client.GetStream().EndRead(res);
            MailClient.AsyncState state = (MailClient.AsyncState)res.AsyncState;
            string answer = Aes.DecryptStringFromBytes_Aes(state.buffer, state.AES_KEY, state.AES_IV);
            if (answer.Contains("OK"))
            {
                string[] answer_params = answer.Split(',');
                LoggedUserInfo.USER_ID = Convert.ToInt32(answer_params[1]);
                LoggedUserInfo.USER_LOGIN = answer_params[2];

                //zalogowano
                //this.TargetWindow = new MessageListsWindow();
                Dispatcher.CurrentDispatcher.Invoke(DispatcherPriority.Background, new Action(() => this.TargetWindow = new MessageListsWindow()));
                //System.Windows.Application.Current.Dispatcher.Invoke(DispatcherPriority.Background,  new Action(() => this.TargetWindow = new MessageListsWindow()));
            }
            else
            {
                //zle dane
                System.Windows.MessageBox.Show("Zle dane");
            }
        }
        catch(Exception exep) { }
    }

This is declaration of asyncSendEncryptedProtocolMessage

asyncSendEncryptedProtocolMessage(string message, AsyncCallback callBack)

use function

clientStream.BeginWrite(encryptedMessage, 0, encryptedMessage.Length, callBack, st);

when code executes I get exception "The calling thread must be STA, because many UI components require this." I read about "SetApartmentState(ApartmentState.STA);" but I don't know how to apply it to callback. I've also tried with STAThread attribute but it doesn't work. I use MVVM Light framework.

StackTrace

" w System.Windows.Threading.DispatcherObject.VerifyAccess()\r\n   w System.Windows.Application.get_MainWindow()\r\n   w MailClient.ViewModel.MainWindowModel.LoginInfo_recieved(IAsyncResult res) w c:\\Users\\oem\\Documents\\Visual Studio 2012\\Projects\\MvvmLight3\\MailClient\\ViewModel\\MainWindowModel.cs:wiersz 171"

回答1:

 public static void Dispatch(this DispatcherObject source, Action func)
    {
        if (source.Dispatcher.CheckAccess())
            func();
        else
            source.Dispatcher.Invoke(func);
    }

And then use it like this:

MailClient.Helpers.Client.getInstance()
.asyncRecieveEncryptedProtocolMessage(new AsyncCallback(()=> 
Application.Current.MainWindow.Dispatch(LoginInfo_recieved)));

来源：https://stackoverflow.com/questions/16080355/how-to-update-gui-in-c-sharp-wpf-from-asynchronous-method-callback

标签

.net

wpf

asynchronous

mvvm-light