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POStopping TextBox flicker during update
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copied!<p>My WinForms application has a TextBox that I'm using as a log file. I'm appending text without the form flickering using <code>TextBox.AppendText(string);</code>, however when I try to purge old text (as the control's .Text property reaches the .MaxLength limit), I get awful flicker.</p> <p>The code I'm using is as follows:</p> <pre><code>public static void AddTextToConsoleThreadSafe(TextBox textBox, string text) { if (textBox.InvokeRequired) { textBox.Invoke(new AddTextToConsoleThreadSafeDelegate(AddTextToConsoleThreadSafe), new object[] { textBox, text }); } else { // Ensure that text is purged from the top of the textbox // if the amount of text in the box is approaching the // MaxLength property of the control if (textBox.Text.Length + text.Length > textBox.MaxLength) { int cr = textBox.Text.IndexOf("\r\n"); if (cr > 0) { textBox.Select(0, cr + 1); textBox.SelectedText = string.Empty; } else { textBox.Select(0, text.Length); } } // Append the new text, move the caret to the end of the // text, and ensure the textbox is scrolled to the bottom textBox.AppendText(text); textBox.SelectionStart = textBox.Text.Length; textBox.ScrollToCaret(); } } </code></pre> <p>Is there a neater way of purging lines of text from the top of the control that doesn't cause flickering? A textbox doesn't have the BeginUpdate()/EndUpdate() methods that a ListView has.</p> <p>Is a TextBox control even the best suited control for a console log?</p> <p>Edit: The TextBox flickering appears to be the textbox scrolling up to the top (while I purge the text at the top of the control), and then it immediately scrolls back down to the bottom. - it all happens very quickly, so I just see repeated flickering.</p> <p>I've also just seen <a href="https://stackoverflow.com/questions/383813/best-approach-to-windows-forms-rolling-log-output-in-textbox">this question</a>, and the suggestion was to use a ListBox, however I don't know if this will work in my situation, as (in most cases) I'm receiving the text for the ListBox one character at a time.</p>

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