CodeGuru Home VC++ / MFC / C++ .NET / C# Visual Basic VB Forums Developer.com
Results 1 to 2 of 2
  1. #1
    Join Date
    Sep 2011

    Cross-Thread Operation Not Valid

    I am trying to run the following code in a thread but I keep getting this error for both listboxes:

    Cross-thread operation not valid

    Heres the code I am using:

        for (int i = 0; i < listBox4.Items.Count; i++)
        listBox4.SetSelected(i, true);
        listBox5.SetSelected(i, true);
        string[] details = { listBox4.SelectedItem.ToString(), listBox5.SelectedItem.ToString() };
        foreach (string element in details)
        string postData = "";
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create("");
        request.ContentType = "application/x-www-form-urlencoded";
        request.ContentLength = postData.Length;
        request.Method = "POST";
        request.KeepAlive = true;
        Stream response = request.GetRequestStream();
        byte[] postBytes = Encoding.ASCII.GetBytes(postData);
        response.Write(postBytes, 0, postBytes.Length);
        catch (Exception ex)

    (I removed my postData and the site I am requesting too to protect my code form leechers)

  2. #2
    Arjay's Avatar
    Arjay is offline Moderator / MS MVP Power Poster
    Join Date
    Aug 2004

    Re: Cross-Thread Operation Not Valid

    Quote Originally Posted by kytro360 View Post
    (I removed my postData and the site I am requesting too to protect my code form leechers)
    Here's a head's up....

    No one cares about code that can be found in any sample and that anyone can write.

    If you don't want to post code, fine, but there isn't any need to comment about 'leechers'. It's insulting to folks on this site that are trying to help.

    Now, to solve your problem, search bing or google for "Cross-thread operation not valid".

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Windows Mobile Development Center

Click Here to Expand Forum to Full Width

On-Demand Webinars (sponsored)

We have made updates to our Privacy Policy to reflect the implementation of the General Data Protection Regulation.