使用WCF处理回叫时更新进度

Question

我有一个程序可以访问我通过HTTP运行的WCF Web服务。

程序需要登录，登录过程如下：

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

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

但是当我尝试从这些handlecallback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;
    }

    }

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;
        }
    ));