跨线程操作无效 [英] Cross-thread operation not is valid

问题描述

我是一个较新的c＃程序员，我不知道如何在我的运行错误中处理我的serach结果



调试时我一直收到以下错误。 />

跨线程操作无效：控制'  txtDataRx'从其创建的线程以外的线程访问。

这是它所指的代码：

  public   void  OnDataReceived（IAsyncResult asyn）
 {
  try  
 {
 CSocketPacket theSockId =（CSocketPacket）asyn.AsyncState; 
  //   end receive ...  
  int  iRx =  0 ; 
 iRx = theSockId.thisSocket.EndReceive（asyn）; 
  char  [] chars =  new   char  [iRx +  1 ]; 
 System.Text.Decoder d = System.Text.Encoding.UTF8.GetDecoder（）; 
  int  charLen = d.GetChars（theSockId.dataBuffer， 0 ，iRx，chars，< span class =code-digit> 0 ）; 
 System。 String  szData =  new  System。串（字符）; 
 txtDataRx.Text = txtDataRx.Text + szData; 
 WaitForData（m_socWorker）; 
} 
  catch （ObjectDisposedException）
 {
 System.Diagnostics.Debugger.Log（ 0 ，  1，  \ nOnnDataReceived：套接字已关闭\ n）; 
} 
  catch （SocketException se）
 {
 MessageBox.Show（se.Message）; 
} 
} 
 

有人可以请帮助我解决这个问题？

请!!!!!!!

解决方案

您正在从其他线程更新UI控件。



而不是直接更新它，

 txtDataRx.Text = txtDataRx.Text + szData; 

代替使用代表，



例如定义一个代表

 委托  void  UpdateTextBoxCallBack（TextBox txtBox， string  strText）; 

创建一个方法，更新此文本框，如下所示。

  public   void  UpdateTextBox（TextBox txtBox， string  strText）
 {
 <跨度lass =code-keyword> if （txtBox.InvokeRequired）
 {
 UpdateTextBoxCallBack upcb =  new  UpdateTextBoxCallBack（UpdateTextBox）; 
  this  .Invoke（upcb， new   object  [] {txtBox，strText}）; 
} 
  else  
 {
 txtBox.Text = strText; 
} 
} 

以及何时需要更新此文本框从其他一些线程。只需调用方法

 UpdateTextBox（txtBox， 要更新的新文本）; 

希望这会有所帮助。



-praveen。

您只能从创建它的线程（即UI线程）访问该控件。在其他线程（如BackgroundWorker）中，您需要使用 Control.BeginInvoke [ ^ ]或 Control.Invoke [ ^ ]。



替换以下代码

< pre lang =c＃> txtDataRx.Text = txtDataRx.Text + szData;

with

 < span class =code-keyword> this  .BeginInvoke（ new  MethodInvoker（ delegate （ ）
 {
  this  .txtDataRx.AppendText（szData）; 
}））; 

然后尝试它是否有效。



祝你好运

i am a newer c# programmer and i dont know how to work my serach result in my accourding error

I keep getting the following error when debugging.

Cross-thread operation not valid: Control 'txtDataRx' accessed from a thread other than the thread it was created on.

Here's the code that it points to:

public  void OnDataReceived(IAsyncResult asyn)
    {
        try
        {
            CSocketPacket theSockId = (CSocketPacket)asyn.AsyncState ;
            //end receive...
            int iRx  = 0 ;
            iRx = theSockId.thisSocket.EndReceive (asyn);
            char[] chars = new char[iRx +  1];
            System.Text.Decoder d = System.Text.Encoding.UTF8.GetDecoder();
            int charLen = d.GetChars(theSockId.dataBuffer, 0, iRx, chars, 0);
            System.String szData = new System.String(chars);
            txtDataRx.Text = txtDataRx.Text + szData;
            WaitForData(m_socWorker );
        }
        catch (ObjectDisposedException )
        {
            System.Diagnostics.Debugger.Log(0,"1","\nOnDataReceived: Socket has been closed\n");
        }
        catch(SocketException se)
        {
            MessageBox.Show (se.Message );
        }
    }

Can somebody please help me fix this?
please!!!!!!!

解决方案

You are updating a UI control from a different thread.

instead of updating it directly,

txtDataRx.Text = txtDataRx.Text + szData;

instead use a delegate,

e.g define a delegate

delegate void UpdateTextBoxCallBack(TextBox txtBox, string strText);

create a method, to update this text box as shown below.

public void UpdateTextBox (TextBox txtBox, string strText)
{
      if (txtBox.InvokeRequired)
      {
          UpdateTextBoxCallBack upcb = new UpdateTextBoxCallBack(UpdateTextBox);
          this.Invoke(upcb, new object[] { txtBox, strText});
      }
      else
      {
           txtBox.Text = strText ;
      }
}

and when you need to update this text box from some other thread. just call the method

UpdateTextBox (txtBox, "New Text to be updated" );  

hope this helps.

-praveen.

You can only access the control from the thread where it was created(that is, the UI thread). In other threads(like your BackgroundWorker), you need to use Control.BeginInvoke[^] or Control.Invoke[^].

Replace your following code

txtDataRx.Text = txtDataRx.Text + szData;

with

this.BeginInvoke(new MethodInvoker(delegate()
{
   this.txtDataRx.AppendText(szData);
}));

and then try if it works.

Good luck

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