datagridview中输入密码，显示星号*

datagridview中输入密码，显示星号*
private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
{
    if (this.dataGridView1.Columns[e.ColumnIndex].Name == "password" && e.Value != null && e.Value.ToString().Length > 0)
    {
        e.Value = new string('*', e.Value.ToString().Length);
    }

}
 

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
    TextBox t=e.Control as TextBox;
    for (int i=0;i<dataGridView1.Rows.Count;i++)
    {
        if (this.dataGridView1.Columns[i].Name == "password")
            t.PasswordChar = '*';
        else
            t.PasswordChar = new char();
    }
}