c# - 使用 WCF 处理回调时更新进度

Question

我有一个程序可以访问通过 HTTP 运行的 WCF Web 服务。

程序需要登录，登录过程是这样的：

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

我想在每个阶段之后更新进度。所以我想我会通过 IAsycnhResult 方法链接它们..

但是，当我尝试从这些句柄回调方法更新进度时，我收到一个错误：

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

代码：

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;
    }

    }

您如何安全地更新进度？

Answer 1

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