date on DataGridView not formatting as expected

I have a column that uses the DateTime format that was set in the column styles.

When a user en开发者_如何转开发ters a date, it's not formatting it to the style that it is set to. As a matter of fact, it isn't doing anything to the field. I put gibberish in there and it takes it.

Am I missing something here? Shouldn't it at least format the date or give an error for wrong date format?

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Try handling an event on the datagridview, getting the text input and validating whether it's a date or not. I used the event CellEndEdit, but choose yours as you like.

private void CheckCellValue(object sender, DataGridViewCellEventArgs e)
{
        //my column index on the date is 0; modify yours as needed!
    if (e.ColumnIndex == 0 && e.RowIndex > -1 && e.RowIndex != dataGridView1.NewRowIndex)
    {
        //check whether this can be parsed as a date.
        string enteredVal = dataGridView1.CurrentCell.Value.ToString();
        DateTime dt;
        if (DateTime.TryParse(enteredVal, out dt))
        {
            dataGridView1.CurrentCell.Value = dt.ToString("dd-MMM-yyyy");
        }
        else
        {
            MessageBox.Show("Doh, that's not a date: " + enteredVal);
        }
    }
}