C # controls created in one thread cannot be filtered to a control in another thread
I start a thread and this thread grabs information and creates labels and displays it, here is my code
private void RUN()
{
Label l = new Label();
l.Location = new Point(12, 10);
l.Text = "Some Text";
this.Controls.Add(l);
}
private void button1_Click(object sender, EventArgs e)
{
Thread t = new Thread(new ThreadStart(RUN));
t.Start();
}
The funny thing is I had a previous app with a panel and I used to add controls to it using streams without any problem, but this one won't let me do it.
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3 answers
You cannot update the UI thread from another thread:
private void RUN()
{
if (this.InvokeRequired)
{
this.BeginInvoke((MethodInvoker)delegate()
{
Label l = new Label(); l.Location = new Point(12, 10);
l.Text = "Some Text";
this.Controls.Add(l);
});
}
else
{
Label l = new Label();
l.Location = new Point(12, 10);
l.Text = "Some Text";
this.Controls.Add(l);
}
}
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You are trying to add a control to a parent control from a different thread, controls can only be added to the parent from the parent control!
use Invoke to safely access the UI thread from another thread:
Label l = new Label();
l.Location = new Point(12, 10);
l.Text = "Some Text";
this.Invoke((MethodInvoker)delegate
{
//perform on the UI thread
this.Controls.Add(l);
});
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