Question

我已经阅读了很多有关这些内容的信息，我试过这个：

class Server
{
... 
  public Server(int Port, ListBox ex_lb, PictureBox ex_pb)
  {
    ServerWork = new Thread(() => ServerFunction(Listener, ex_lb, ex_pb));
    ServerWork.Start();
  }
  static void ServerFunction(TcpListener ex_listener, ListBox ex_lb, PictureBox ex_pb)
  {
    //and any access to ex_lb throws exception, didnt debug to access to ex_pb
  }
}

这样：

private static IncomingDataClass g_IDC = new IncomingDataClass();

private class IncomingDataClass
{
  static string data = "";
  public string Data
  {
    get { return data; }
    set { 
      data = value;
      SomeEvent(this,null,data);
    }
  }            
}

void IncomingDataClass_SomeEvent(object sender, EventArgs e, string ex_data)
{
  if (ex_data.Contains("listbox"))
  {
    ex_data = ex_data.Remove(ex_data.IndexOf("listbox"), "listbox".Length);
    listBox1.Items.Add(ex_data);
  }
}

delegate void MyEventHandler(object sender, EventArgs e, string ex_data);
static event MyEventHandler SomeEvent;
// in form load event
SomeEvent += IncomingDataClass_SomeEvent;
class Server
{
... 
  public Server(int Port, ListBox ex_lb, PictureBox ex_pb)
  {
    ServerWork = new Thread(() => ServerFunction(Listener));
    ServerWork.Start();
  }
  static void ServerFunction(TcpListener ex_listener)
  {
    //and any change of g_IDC.Data throws exception here
  }
}

这样：

private static ListBox listBox1 = new ListBox();

private void Form1_Load(object sender, EventArgs e)
{
  ...
  listBox1.FormattingEnabled = true;
  listBox1.Location = new System.Drawing.Point(12, 256);
  listBox1.Name = "listBox1";
  listBox1.Size = new System.Drawing.Size(258, 108);
  listBox1.TabIndex = 6;
  Controls.Add(listBox1);
}
//anyways, even if i create new ListBox lb = listBox1 in ServerFunction(..), it throws System.InvalidOperationException => Access attempt to listBox1 not from thread where is was created.

我做错了什么？我认为创建静态控件是解决此问题的最终问题，但即使这样也无法工作......

Answer 1

如果我没记错，为了从另一个线程更新UI，你需要使用这个调用：

this.Invoke((MethodInvoker)delegate
    {
        MethodForUpdatingUI();
    });

这将从UI线程启动MethodForUpdatingUI()，使您可以访问控件。

因此，要在代码中使用它，我会尝试更改IncomingDataClass_SomeEvent：

void IncomingDataClass_SomeEvent(object sender, EventArgs e, string ex_data)
{
        this.Invoke((MethodInvoker)delegate
        {
            UpdateListBox(ex_data);
        });
}

UpdateListBox(string ex_data)
{
  if (ex_data.Contains("listbox"))
  {
    ex_data = ex_data.Remove(ex_data.IndexOf("listbox"), "listbox".Length);
    listBox1.Items.Add(ex_data);
  }
}

如果不是你要求的情况，请随时纠正我，否则这是一个不好的实践。我没有测试过代码。

Answer 2

您只能从UI线程处理UI控件。如果那些控制是静态的，那么无关紧要。使用Dispatcher对象或SynchronizationContext对象来修改来自不同线程的控件。

从静态线程函数访问控制元素

2 个答案: