在datagridview的单元格中按键事件并返回键

代码运行时，我使用键A。但是当我使用with键返回时，代码不运行。

    void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
    {
        TextBox txt = e.Control as TextBox;
        txt.KeyPress += new KeyPressEventHandler(txt_KeyPress);
    }
    void txt_KeyPress(object sender, KeyPressEventArgs e)
    {
        /* Code run. */
        if(e.KeyChar == (char)Keys.A)
        {
            MessageBox.Show("Hello");
        }
        /* Code not run! */
        if (e.KeyChar == (char)Keys.Return)
        {
            MessageBox.Show("Hello");
        }
    }

但如果我尝试使用文本框，它会运行

void TextBox1_KeyDown(object sender, KeyEventArgs e) 
{ 
    if (e.KeyCode == Keys.Enter) 
    { 
        e.Handled = true; 
    } 
}
void TextBox1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e) 
{ 
    if (e.KeyCode == Keys.Return)
    {
        /* Your code here! */ 
    }
}