[RESOLVED] Validation on multiple fields?

Im trying to validate all the fields before I enable the calcButton. The issue I'm having is that the errorMessage doesn't clear once i enter a correct value. Hence the calcButton is disabled. How can I clear the ErrorProvider once the validation is good?

This code is probably not the write way to do it. Any advice on a better way to code it would be greatly appreciated, and if you have some sample coding that would be icing on the cake.

Thanks again.

VB Code:

Private Sub SetFormErrorState()
        Dim errorMessage As String = Nothing
        'Checking CC# for numeric
        If Not Me.ValidateTextBox(Me.phoneTextBox.Text) Then
            'The user has not entered the required value.
            errorMessage = "Entry Required"
            'Checking phone for numeric
            Me.ErrorProvider.SetError(Me.phoneTextBox, errorMessage)
 
        ElseIf Me.ccTextBox.Enabled AndAlso Not Me.ValidateTextBox(Me.ccTextBox.Text) Then
            'The user has not entered the required value.
            errorMessage = "Entry Required"
            Me.ErrorProvider.SetError(Me.ccTextBox, errorMessage)
 
        ElseIf Not Me.ValidateTextBox(Me.startMiTextBox.Text) Then
            'The user has not entered the required value.
            errorMessage = "Entry Required"
            Me.ErrorProvider.SetError(Me.startMiTextBox, errorMessage)
 
        ElseIf Not Me.ValidateTextBox(Me.endMiTextBox.Text) Then
            'The user has not entered the required value.
            errorMessage = "Entry Required"
            Me.ErrorProvider.SetError(Me.endMiTextBox, errorMessage)
 
        ElseIf Not Me.ValidateTextBox(Me.daysRentedTextBox.Text) Then
            'The user has not entered the required value.
            errorMessage = "Entry Required"
            Me.ErrorProvider.SetError(Me.daysRentedTextBox, errorMessage)
        Else
            Me.ErrorProvider.Clear()
        End If
 
        'Enable the OK button if and only if there are no errors.
        Me.calculateButton.Enabled = (errorMessage Is Nothing)
    End Sub
 
    Private Function ValidateTextBox(ByVal varTextBoxString As String) As Boolean
        If varTextBoxString = "" Then
            Return False
        Else
            Return True
        End If
        'Return True if the TextBox contains any value, otherwise return False.
    End Function

You need to handle the error for each TextBox separately and each time the text changes. This works as you'd expect:

VB Code:

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Me.SetErrorState()
End Sub
 
Private Sub TextBox_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox3.TextChanged, _
                                                                                                    TextBox2.TextChanged, _
                                                                                                    TextBox1.TextChanged
    Me.SetErrorState()
End Sub
 
Private Sub SetErrorState()
    Const ERR_MSG As String = "Required field"
    Dim errCount As Integer = 0
 
    If Me.ValidateNonEmptyString(Me.TextBox1.Text) Then
        Me.ErrorProvider1.SetError(Me.TextBox1, Nothing)
    Else
        Me.ErrorProvider1.SetError(Me.TextBox1, ERR_MSG)
        errCount += 1
    End If
 
    If Me.ValidateNonEmptyString(Me.TextBox2.Text) Then
        Me.ErrorProvider1.SetError(Me.TextBox2, Nothing)
    Else
        Me.ErrorProvider1.SetError(Me.TextBox2, ERR_MSG)
        errCount += 1
    End If
 
    If Me.ValidateNonEmptyString(Me.TextBox3.Text) Then
        Me.ErrorProvider1.SetError(Me.TextBox3, Nothing)
    Else
        Me.ErrorProvider1.SetError(Me.TextBox3, ERR_MSG)
        errCount += 1
    End If
 
    Me.Button1.Enabled = (errCount = 0)
End Sub
 
Private Function ValidateNonEmptyString(ByVal str As String) As Boolean
    Return str.Trim().Length > 0
End Function

There are ways to reduce the code but that's the general idea. The more TextBoxes that have different validation requirements, such as the one that might be disabled, the less you could reduce the code.

VB Code:

Private Sub PaymentTypeComboBox_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles PaymentTypeComboBox.SelectedIndexChanged
        'disable the ccTextBox if "Cash" is selected
        Me.ccTextBox.Enabled = (CStr(Me.PaymentTypeComboBox.SelectedItem) <> "Cash")
    End Sub
 
    Private Sub ccTextBox_PropertyChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ccTextBox.EnabledChanged, ccTextBox.TextChanged
        'Clear the TextBox if it is disabled.
        If Not Me.ccTextBox.Enabled Then
            Me.ccTextBox.Clear()
        End If
 
        'Set the properties of the OK button and ErrorProvider appropriately for the state of the TextBox.
        Me.SetFormErrorState()
    End Sub
Private Sub SetFormErrorState()
        Const ERR_MSG As String = "Entry Required"
        Dim errCount As Integer = 0
 
 
        If Me.ValidateNonEmptyString(Me.phoneTextBox.Text) Then
            Me.ErrorProvider.SetError(Me.phoneTextBox, Nothing)
        Else
            Me.ErrorProvider.SetError(Me.phoneTextBox, ERR_MSG)
            errCount += 1
        End If
 
        If Me.ccTextBox.Enabled AndAlso Me.ValidateNonEmptyString(Me.ccTextBox.Text) Then
            Me.ErrorProvider.SetError(Me.ccTextBox, Nothing)
        Else
            Me.ErrorProvider.SetError(Me.ccTextBox, ERR_MSG)
            errCount += 1
        End If
 
        If Me.ValidateNonEmptyString(Me.startMiTextBox.Text) Then
            Me.ErrorProvider.SetError(Me.startMiTextBox, Nothing)
        Else
            Me.ErrorProvider.SetError(Me.startMiTextBox, ERR_MSG)
            errCount += 1
        End If
 
        If Me.ValidateNonEmptyString(Me.endMiTextBox.Text) Then
            Me.ErrorProvider.SetError(Me.endMiTextBox, Nothing)
        Else
            Me.ErrorProvider.SetError(Me.endMiTextBox, ERR_MSG)
            errCount += 1
        End If
 
        If Me.ValidateNonEmptyString(Me.daysRentedTextBox.Text) Then
            Me.ErrorProvider.SetError(Me.daysRentedTextBox, Nothing)
        Else
            Me.ErrorProvider.SetError(Me.daysRentedTextBox, ERR_MSG)
            errCount += 1
        End If
 
        If errCount = 0 Then
            Me.ErrorProvider.Clear()
        End If
 
        'Enable the OK button if and only if there are no errors.
        Me.calculateButton.Enabled = (errCount = 0)
    End Sub

everything works great, but when the ccTextBox is disabled, the error still shows up "Entry Required!"

VB Code:

If Me.ccTextBox.Enabled AndAlso Me.ValidateNonEmptyString(Me.ccTextBox.Text) Then
            Me.ErrorProvider.SetError(Me.ccTextBox, Nothing)
        Else
            Me.ErrorProvider.SetError(Me.ccTextBox, ERR_MSG)
            errCount += 1
        End If

Is this part look right?

No it doesn't. Ask yourself, when do you want to display an error on ccTextBox and when do you not, then ask yourself whether the condition you've used will do that. Where will that code go if the Enabled property is False?

VB Code:

If Me.ccTextBox.Enabled AndAlso Not Me.ValidateNonEmptyString(Me.ccTextBox.Text) Then
            Me.ErrorProvider.SetError(Me.ccTextBox, ERR_MSG)
            errCount += 1
        Else
            Me.ErrorProvider.SetError(Me.ccTextBox, Nothing)
        End If

changed it to the above to make it work right

Not that there's anything wrong with that but for future reference note that the following would also work:

VB Code:

If Not Me.ccTextBox.Enabled OrElse Me.ValidateNonEmptyString(Me.ccTextBox.Text) Then
            Me.ErrorProvider.SetError(Me.ccTextBox, Nothing)
        Else
            Me.ErrorProvider.SetError(Me.ccTextBox, ERR_MSG)
            errCount += 1
        End If

If you weren't going to use an Else block then that might be preferable. As you are using an Else block neither is any better than the other.