My WinForms application has a TextBox that I'm using as a log file. I'm appending text without the form flickering using TextBox.AppendText(string);
, however when I try to purge old text (as the control's .Text property reaches the .MaxLength limit), I get awful flicker.
The code I'm using is as follows:
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("
");
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();
}
}
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.
Is a TextBox control even the best suited control for a console log?
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.
I've also just seen this question, 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.
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