[RESOLVED] [2005] Validating MaskedTextBox defined as a Date?

[blakemckenna]

I have a maskedtextbox control on a form. It's defined as a date field using the " / / " mask. My code has a loop that checks for several different kinds of masks. My problem is when it encounters a "Date", it doesn't pass the edit because my first check is the "Length" of the field. I always check for > 0, well in this case it is but it looks like " / / ". So it passes that check. Then I check for "IsDate" and it fails there. This scenario is possible when it encounters a date field that hasn't yet been populated. How can I properly check this maskedTextBox?

Thanks,

[dolot]

So are you saying that the " / / " fails when in actuality it should pass? I would think that the " / / " failing is what you would want?

Me thinks I'm not understanding.

[BruceG]

For this masked edit box, set TextMaskFormat property to "ExcludePromptAndLiterals". Doing that will cause the Length function to only count the characters entered by the user. It will not count the slashes.

[blakemckenna]

Bruce,

Your suggestion makes sense, however, I still seem to be doing alot of validation for this field. Here is what my code looks like:

            
For x As Integer = 0 To intElementsChosen - 1
      If arrRQElements(x).controlType <> "DATE" Then
      Else
          If txtBox.TextLength > 0 Then
              If IsNumeric(txtBox.Text) Then
                  If IsDate(txtBox.Text) Then
                  Else
                      MessageBox.Show("Invalid Date Format!", "Format Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
                      txtBox.Text = ""
                      txtBox.Focus()
                  End If
              End If
          End If
      End If
 
      If txtBox.Name = arrRQElements(x).labelName Then
         arrRQElements(x).fieldData = txtBox.Text
         txtDetails.Enabled = True
         Exit For
      End If
Next

Doesn't this seem like overkill. Plus, when I type in a date value, ex: 010108, I tried converting it to a date and it didn't like it.

      txtBox.Text = CDate(txtBox.Text)

What would be the best way to edit this?

Thanks,

[BruceG]

Blake, there is any number of ways to do this, but I'm thinking the easiest way is to set the TextMaskFormat property back to "IncludePromptAndLiterals" and rather than to see if the length is zero, test the control's text for a value of "__/__/____" (that would mean no text has been entered). When populated, this will make the IsDate test easier, because the IsDate function will only give you the expected result if the value being tested "looks like" a date (i.e. with slashes, dashes, or even a string like "June 17, 2008").
I modified your code below. Note: You need not do a numeric test here.

For x As Integer = 0 To intElementsChosen - 1
      If arrRQElements(x).controlType <> "DATE" Then
      Else
          If txtBox.Text <> "__/__/____" Then
              'If IsNumeric(txtBox.Text) Then
                  If IsDate(txtBox.Text) Then
                  Else
                      MessageBox.Show("Invalid Date Format!", "Format Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
                      txtBox.Text = ""  ' you may want to skip clearing this (i.e. let the user see what they did wrong)
                      txtBox.Focus()
                  End If
              'End If
          End If
      End If
 
      If txtBox.Name = arrRQElements(x).labelName Then
         arrRQElements(x).fieldData = txtBox.Text
         txtDetails.Enabled = True
         Exit For
      End If
Next

Also - you should only do a CDate on a string variable that "looks like" a date, as described above (with the punctuation etc.). Doing a CDate on a string of numbers will not give you the expected result or will fail.

In some situations (not this error-checking scenario), you may find yourself writing statements like:
If IsDate(s) Then
MyDateVar = CDate(s)
End If

HTH
Bruce

[jmcilhinney]

There's only one validation you should be doing:

Dim d As Date
 
If Date.TryParse(myMaskedTextBox.Text, d) Then
    'd contains the value.
Else
    'Invalid input.
End If

That said, why don't you just use a DateTimePicker?

[blakemckenna]

JMC,

Actually that is a better idea using the DTP. Question about the DTP though...how do you prevent the user from entering a date. I want the user to be able to click the drop down calendar ONLY as a source for getting the value.

thx

[kleinma]

Why would you want to limit your users to only be able to use the control 1 way when it works perfectly fine 2 ways?

[blakemckenna]

After playing around with it...I guess you can't enter an invalid date. So...problem solved altogether!

Thx kleinma