Question

I have a textbox with the Text property bound to a dataset column with the DataType set to System.DateTime.
The FormatString on the Binding is set to dd-MM-yyyy.

When the user enters a date it attempts to convert it to a date but can come up with some strange values for a seemingly invalid date.

For example:

textBox1.Text = '01-02-200'; 

Should be an invalid date but it formats it as 01-02-0200.

Is there an easy way to catch these out-of-bounds values either through setting a valid range or overriding an event on the binding/textbox?

Answer 1

A .NET DateTime is in the range 01/01/0001 to 31/12/9999 23:59:59.9999999, so 01/01/200 is considered to be valid.

You can validate the input and restrict the range: the Validating event would be the place to do your validation. You’ll need to parse the string into a DateTime and validate its range.

The allowed range will be application dependent. For example, the following code will restrict the datetime to values that can be stored in a SQL Server 2005 DATETIME column (01-01-1753 to 31-12-999):

private void textBox1_Validating(object sender, CancelEventArgs e) {     DateTime date;     if (!DateTime.TryParseExact(textBox1.Text,          'dd-MM-yyyy',          CultureInfo.CurrentCulture,          DateTimeStyles.None,          out date))     {         MessageBox.Show(textBox1.Text + ' is not a valid date');         textBox1.Focus();         e.Cancel = true;         return;     }     if ((date < (DateTime) System.Data.SqlTypes.SqlDateTime.MinValue) ||         (date > (DateTime) System.Data.SqlTypes.SqlDateTime.MaxValue))     {         MessageBox.Show(textBox1.Text + ' is out of range');         textBox1.Focus();         e.Cancel = true;         return;     } }