CODEWITHSUNDEEP
c#multithreadingwinforms
user1477701
user1477701

Reputation: 147

toolStripStatusLabel in multithreading

I am using toolStripStatusLabel in multithreading and although it is another thread which interact with the toolStripStatusLabel my invokeRequired method of the statusStrip always return false (I enforce the creation of the handle also). In this thread I can access the toolStripStatusLabel (from else clause), update it but my editing could not be shown in the main UI. Here is my code:

public void safeThreaded()
{                
    Form2 form = new Form2();
    StatusStrip ss = (StatusStrip)form.Controls["statusStrip1"];
    ToolStripStatusLabel label =   (ToolStripStatusLabel)ss.Items["toolStripStatusLabel1"];
    string text = "Written by the background thread.";
    if (!(ss.IsHandleCreated))
    {
        IntPtr handler = ss.Handle;
    }
    if (ss.InvokeRequired)
    {
        ss.Invoke(new updateTextCallback(updateText), new object[]{"Text generated on non-UI thread."});
    }
    else
    {
        // It's on the same thread, no need for Invoke
        label.Text = text + " (No Invoke)";
        MessageBox.Show(label.Text.ToString());
        ss.Refresh();
    }
}

private void updateText(string text)
{
    Form2 form = new Form2();
    StatusStrip ss = (StatusStrip)form.Controls["statusStrip1"];
    ToolStripStatusLabel label = (ToolStripStatusLabel)ss.Items["toolStripStatusLabel1"];
    label.Text = text;
}

public delegate void updateTextCallback(string text);

Upvotes: 1

Views: 2863

Answers (1)

Gjeltema
Gjeltema

Reputation: 4166

It's because the owning thread is whatever thread you're calling safeThreaded() from - you're creating the Form with the StatusStrip and ToolStripStatusLabel, and then editing it all in the same thread.

If you were to create the Form in one thread, and then run your safeThreaded() function (without creating the Form2 in it) in a separate thread, then you should see InvokeRequired be true.

Upvotes: 1

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