private delegate void TextAppendDelegate(TextBox txt, string text);
public void TextAppend(TextBox txt, string text)
{
if(txt.InvokeRequired)
txt.Invoke(new TextAppendDelegate(TextAppend), new object[] {txt, text });
else
{
if(txt.Lines.Length == 1000)
{
txt.SelectionStart = 0;
txt.SelectionLength = txt.Text.IndexOf("\n", 0) + 1;
txt.SelectedText = "";
}
txt.AppendText(text + "\n");
txt.ScrollToCaret();
}
}