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VB.Net WinForm Validation ErrorProvider regular expression

I would like to validate a text box on a windows form in VB.Net to check first that the required field has a value and then check to make sure it matches the RegEx. This is a Windows Form and not ASP. I have been trying ErrorProvider and I can get it to check for a required feild, but not then check the same textbox for the regex.

Thank you.

Private Sub TruckNoTextBox_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles TruckNoTextBox.Validating
        Dim Regex As New Regex("^[Y,S,0-9]{1,4}$")
        If Regex.IsMatch(TruckNoTextBox.Text) Then
            ErrorProvider2.SetError(TruckNoTextBox, "Please enter correct format")
        Else
            ErrorProvider2.SetError(TruckNoTextBox, "Wrong")

        End If

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rawinnlnx9

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rtay

ASKER

Your validate() soultion did the trick. Now for the second part, how can I check to make sure the field is not empty first and then if it is not empy check the regex. Here is the code working for regex.

Private Sub TruckNoTextBox_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles TruckNoTextBox.Validating
Dim Regex As New Regex("^[Y,S,0-9]{1,4}$")
If Regex.IsMatch(TruckNoTextBox.Text) Then
ErrorProvider2.SetError(TruckNoTextBox, "")
Else
ErrorProvider2.SetError(TruckNoTextBox, "Wrong")

End If
Me.Validate()

End Sub

rtay

ASKER

got it with an elseif

rawinnlnx9

If TruckNoTextBox.Text = "" Then
End If

I'm comparing it to an empty "" but some prefer instead to use String.Empty