private void button1_Click(object sender, System.EventArgs e) { button1.BackColor = SystemColors.Control; RichTextBoxFinds options = 0; int end = atb.TextLength - 1; int start = atb.SelectionStart + atb.SelectionLength; if (checkBox1.Checked) { options |= RichTextBoxFinds.MatchCase; } if (checkBox2.Checked) { options |= RichTextBoxFinds.WholeWord; } if (checkBox3.Checked) { options |= RichTextBoxFinds.Reverse; end = start - 1; start = 0; } if (checkBox4.Checked) { options |= RichTextBoxFinds.NoHighlight; } int pos; string pat = lastfind = comboBox1.Text; pos = atb.Find(pat, start, end, options); if (pos != -1) { atb.Select(pos, pat.Length); atb.ScrollToCaret(); } else { button1.Enabled = false; } }