Validating a date in a textbox - vb.net

Question

I am trying to valid user input in a textbox which will only takes dates or an empty value (hence the textbox vs a date time picker). Here are the conditions:
Only a date value ("dd-mm-yyyy" or "dd-mm-yy)
Must contain only slashes or numbers
The date has to be on the day it is being typed in
This is what I have so far:
Private Sub tbApp1_TextChanged(sender As System.Object, e As System.EventArgs) Handles tbApp1.TextChanged
If Not Me.tbApp1.Text = String.Empty Then
If Not DateTime.TryParseExact(tbApp1.Text.Trim, formats, New Globalization.CultureInfo("en-US"), Globalization.DateTimeStyles.None, dtTemp) Then
If Not tbApp1.Text.Trim = DateTime.Today.Date Then
ErrorProvider1.SetError(tbApp1, "This is not a valid date; Enter in this format ('M/d/yyyy' or 'M/d/yy')")
End If
Else
ErrorProvider1.Clear()
End If
ElseIf Me.tbApp1.Text.Trim = "" Then
ErrorProvider1.Clear()
End If
End Sub
Masked Textbox use
'Private Sub mtbApp1_TypeValidationCompleted(ByVal sender As Object, ByVal e As TypeValidationEventArgs) Handles mtbApp1.TypeValidationCompleted
If Not Me.mtbApp1.Text = String.Empty Then
If (Not e.IsValidInput) Then
ErrorProvider1.SetError(mtbApp1, "The data you supplied must be a valid date in the format mm/dd/yyyy.")
Else
' Now that the type has passed basic type validation, enforce more specific type rules.
Dim UserDate As DateTime = CDate(e.ReturnValue)
If (UserDate = DateTime.Now) Then
ErrorProvider1.SetError(mtbApp1, "The data you supplied must be today's date")
e.Cancel = True
End If
End If
ErrorProvider1.Clear()
End If
End Sub'
I noticed for a date like 03/18/2014 when it loaded back into the masked textbox it converts to 31/82/014. How could i fix this? The query pulls back the field as
CONVERT(VARCHAR(10),Date,101) AS Date
I set it in vb as :
Dim Approval1 As Date = Nothing
and then
If Not IsDBNull(((WorklistsDS.Tables(0).Rows(0).Item("Approval1")))) Then
Approval1 = ((WorklistsDS.Tables(0).Rows(0).Item("Approval1")))
End If
and then loaded into the masked textbox as:
If Approval1 <> Nothing Then
Me.mtbApp1.Text = Approval1
End If

Answer 1

You could also simplify your validation with
If IsDate(tbApp1.Text) Then
'valid date now just check if date falled within permitted range
Dim CompDate As Date = CDate(tbApp1.Text)
Dim MidDate As Date = *enter your min date here*
Dim MaxDate As Date = *enter your max date here*
If CompDate >= MinDate AndAlso CompDate <= MaxDate Then
'Date is within permitted range
......
Else
'Date outside range
'Display error
End If
Else
'text in tbApp1 is not a date
'Display Error
End If