How to validate a date on a Datagridviewtextboxcolumn?

Question

I’m creating a form where the user will input data through a DataGridView, one of the columns of this DataGridView is the type DataGridViewTextBoxColumn and it will receive a date, I would like to validate that date after the user has typed it. Through of that answer at Soen, I discovered the event EditingControlShowing, then I did the following:

private void grdFeriados_EditingControlShowing(object sender, 
    DataGridViewEditingControlShowingEventArgs e)
{
    var controle = e.Control as DataGridViewTextBoxEditingControl;
    // a coluna de index 0 é a coluna que receberá a data
    if (controle != null && ((DataGridView)sender).CurrentCell.ColumnIndex == 0)
    {
        controle.KeyPress -= new KeyPressEventHandler(controle_KeyPress);
        controle.Validating -= new CancelEventHandler(controle_Validating);

        controle.KeyPress += new KeyPressEventHandler(controle_KeyPress);
        controle.Validating += new CancelEventHandler(controle_Validating);
    }
}

private void controle_KeyPress(Object sender, KeyPressEventArgs e)
{
    if (!Char.IsNumber(e.KeyChar) && !e.KeyChar.Equals('/') && !Char.IsControl(e.KeyChar))
    {
        e.Handled = true;
    }
}

private void controle_Validating(object sender, CancelEventArgs e)
{
    var controle = ((DataGridViewTextBoxEditingControl)sender);
    // ValidateUtils é uma classe estática utilizada para validação
    if (!string.IsNullOrEmpty(controle.Text) && !ValidateUtils.IsDate(controle.Text))
    {
        controle.Clear();
        e.Cancel = true;
        MessageBox.Show("Data inválida.", "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}

The event KeyPress works perfectly, accepting only numbers, bar and control characters, however the event Validating does not work as expected, as soon as the error message appears and the user clicks OK, the invalid date goes back to the cell and the focus goes to another row or column, depending on which key was pressed (ENTER or TAB).

Does anyone have any idea how to solve this problem or has another suggestion on how to do this validation?

Note: I tried to reproduce this case in a new project and the same problem was presented.

Answer 1

As @Jota suggested in the comments, I used the event CellValidating together with KeyPress, was like this:

private void dataGridView_EditingControlShowing(object sender, 
    DataGridViewEditingControlShowingEventArgs e)
{
    var controle = e.Control as DataGridViewTextBoxEditingControl;
    if (controle != null)
    {
        controle.KeyPress -= new KeyPressEventHandler(controle_KeyPress);
        if (((DataGridView)sender).CurrentCell.ColumnIndex == 0)
        {
            controle.KeyPress += new KeyPressEventHandler(controle_KeyPress);
        }
    }
}

private void controle_KeyPress(Object sender, KeyPressEventArgs e)
{
    if (!Char.IsNumber(e.KeyChar) && !e.KeyChar.Equals('/') && !Char.IsControl(e.KeyChar))
    {
        e.Handled = true;
    }
}

private void dataGridView_CellValidating(object sender, DataGridViewCellValidatingEventArgs e)
{
    if (e.ColumnIndex == 0 && !string.IsNullOrEmpty((string)e.FormattedValue) && 
        !ValidateUtils.IsDate((string)e.FormattedValue))
    {
        e.Cancel = true;
        MessageBox.Show("Data inválida.", "Aviso", MessageBoxButtons.OK, 
            MessageBoxIcon.Exclamation);
    }
}

Note: the zero column is the one that will receive the date.

Reference:

How to: Validate Data in the Windows Forms Datagridview Control