public void AddLineNumbers()
{
Point pt = new Point(0, 0);
int First_Index = Editor_TextBox.GetCharIndexFromPosition(pt);
int First_Line = Editor_TextBox.GetLineFromCharIndex(First_Index);
pt.X = ClientRectangle.Width;
pt.Y = ClientRectangle.Height;
int Last_Index = Editor_TextBox.GetCharIndexFromPosition(pt);
int Last_Line = Editor_TextBox.GetLineFromCharIndex(Last_Index);
tB_line.SelectionAlignment = HorizontalAlignment.Center;
tB_line.Text = "";
tB_line.Width = getWidth();
for (int i = First_Line; i <= Last_Line + 2; i++)
{
tB_line.Text += i + 1 + "\n";
}
}
