C# Winform 中设置TextBox获取焦点和全选

设置某个TextBox控件自动获取焦点，并且全选里面的内容。 

private void but全选_Click(object sender, EventArgs e)
{
       this.txtSqlResult.Focus();
       this.txtSqlResult.Select(0, this.txtSqlResult.Text.Length);
       this.txtSqlResult.SelectAll();
}