使用WCF處理回叫時更新進度

Question

我有一個程序可以訪問通過HTTP運行的WCF Web服務。

該程序需要登錄，登錄過程如下：

Get Staff List from WebService. 
Gets Drivers List from Webservice.
Gets Vehcile list from web service.
logged in.

我想在每個階段之后更新進度。 所以我想我可以通過IAsycnhResult方法鏈接它們。

但是，當我嘗試通過這些handlecallback方法更新進度時，出現錯誤：

The calling thread cannot access this object because a different thread owns it.

碼：

ASreference.Service1Client client = new ASreference.Service1Client();

private void login()
{
//User has already entered username/password
AsyncCallback CallBack = new AsyncCallback(HandleCallback);
client.BeginGetStaff(CallBack, client);

TxtboxPassword.IsEnabled = false;
TxtboxUsername.IsEnabled = false;
LblProgress.Content = "Logging In";
progress.Value = 10;
}

void HandleCallback(IAsyncResult result)
{
    bool success = false;

    try
    {
        Staff = client.EndGetStaff(result);                
        success = true;
    }
    catch
    {
        MessageBox.Show("Incorrect username or password");
        client = new ASreference.Service1Client();
        EnableTextbox();
    }

    if (success)
    {
        AsyncCallback CallBack = new AsyncCallback(DriversCallBack);                
        client.BeginGetDrivers(CallBack, client);
        LblProgress.Content = "Downloading Drivers";  //CAUSES ERROR
        progress.Value = 30;
    }

    }

您如何安全地更新進度？

Answer 1

progress.Dispatcher.Invoke(
      System.Windows.Threading.DispatcherPriority.Normal,
      new Action(
        delegate()
        {
                LblProgress.Content = "Downloading Drivers";
                progress.Value = 30;
        }
    ));