1 private void button1_Click(object sender, EventArgs e) 2 { 3     if (!(String.IsNullOrEmpty(this.textBox1.Text))) 4     { 5         if (this.richTextBox1.Text.Contains(this.textBox1.Text)) 6         { 7             int loc = this.richTextBox1.Text.IndexOf(this.textBox1.Text, count + 1); 8             if (loc == -1) 9             {10                 MessageBox.Show("查找结束");11                 count = -1;12             }13             else14             {15                 this.richTextBox1.Focus();16                 this.richTextBox1.Select(loc, this.textBox1.Text.Length);17                 count = loc;18             }19         }20     }21 }

注：容易丢失this.richTextBox1.Focus();这段代码