Best way to accomplish this task

Hi all,

In some of my TextBoxes and editable ComboBoxes, I want to make sure that the end-user can only type characters and whitespace but not to allow whitespace without characters existing too.

I have started to write a public sub and would like to know the best way of accomplishing this scenario check. This is what I have so far. Your ideas are welcome.

vb Code:

<CLSCompliant(True)> Public Sub WhiteSpaceAndLettersOnly(ByVal ctrl As Elegant.Ui.Control)
        'This is going to be used on TextBoxes and editable ComboBoxes.
        'This will not be used on txtWorkLog.
        'Allow whitespace and letters only.
        'Do not allow only whitespace without letters existing.
        If TypeOf ctrl Is Elegant.Ui.TextBox Then 'TextBox.
            If Not ctrl.Name Is "txtWorkLog" Then 'Not txtWorkLog.
                If Not String.IsNullOrEmpty(ctrl.Text) Then 'Isnt empty.
 
                End If
            ElseIf TypeOf ctrl Is Elegant.Ui.ComboBox Then
                If DirectCast(ctrl, Elegant.Ui.ComboBox).Editable = True Then
 
                End If
            End If
        End If
    End Sub

OK, I have been researching Regex and this works for letters and spaces but if I type in only spaces, the ErrorProvider doesn't come up. That's expected but how do you make sure spaces are not entered without the existence of letters?

vb Code:

<CLSCompliant(True)> Private Sub txtName_TextChanged(ByVal sender As Object, _
                                                         ByVal e As System.EventArgs) Handles txtName.TextChanged
 
        'Make sure the name is auto titlecased.
        TitleCaseTextBox(txtName)
 
        Dim ErrProv As New ErrorProvider
 
        'Make sure only upper case, lower case and spaces allowed.
        If Not New Regex("^[a-zA-Z\s]*$").IsMatch(txtName.Text) Then
            ErrProv.SetError(txtName, "Value can only contain letters and spaces.")
        Else
            ErrProv.SetError(txtName, "")
        End If

I ain't well-versed with regex, but a simple method could be to check for existence of space and for characters/alphabets separately and if both pass, only then allow. Also have a separate function that takes in a string/text type parameter and checks for the existence of spaces and characters, and return true/false. From the control's textchanged/keypress/lostfocus event, call this function and take action appropriately. This way all the checking will be centralized.

.

Perhaps check for an empty string which is nothing entered or simply spaces entered.

Code:

---

If txtName.Text.Trim.Length > 0 Then
    If Not New Regex("^[a-zA-Z\s]*$").IsMatch(txtName.Text) Then
        ErrProv.SetError(txtName, "Value can only contain letters and spaces.")
    Else
        ErrProv.SetError(txtName, "")
    End If
Else
    ErrProv.SetError(txtName, "")
End If

---

Quote:

---

Originally Posted by kevininstructor

Perhaps check for an empty string which is nothing entered or simply spaces entered.

Code:

---

If txtName.Text.Trim.Length > 0 Then
    If Not New Regex("^[a-zA-Z\s]*$").IsMatch(txtName.Text) Then
        ErrProv.SetError(txtName, "Value can only contain letters and spaces.")
    Else
        ErrProv.SetError(txtName, "")
    End If
Else
    ErrProv.SetError(txtName, "")
End If

---

---

I haven't tested this yet but does it look right?

vb Code:

Public Function WhitespaceLettersOnly(ByVal ctrl As Elegant.Ui.Control) As Boolean
        WhitespaceLettersOnly = False
 
        Dim ErrProv As New ErrorProvider
 
        'Make sure only upper case, lower case and spaces allowed.
        'No spaces allowed without the existence of letters.
        If TypeOf ctrl Is Elegant.Ui.TextBox Then
            If CType(ctrl, Elegant.Ui.TextBox).TextLength > 0 _
            AndAlso Not CType(ctrl, Elegant.Ui.TextBox).TextLength.ToString IsNot Nothing Then
                If Not New Regex("^[azA-Z\s]*$").IsMatch(ctrl.Text) Then
                    ErrProv.SetError(ctrl, "Value may only contain letters and spaces.")
                    WhitespaceLettersOnly = WhitespaceLettersOnly Or True
                ElseIf CType(ctrl, Elegant.Ui.TextBox).TextLength = 0 Then
                    ErrProv.SetError(ctrl, "You must supply a value.")
                    WhitespaceLettersOnly = WhitespaceLettersOnly Or True
                Else
                    ErrProv.SetError(ctrl, "")
                    WhitespaceLettersOnly = WhitespaceLettersOnly Or False
                End If
            End If
        ElseIf TypeOf ctrl Is Elegant.Ui.ComboBox Then
            If CType(ctrl, Elegant.Ui.ComboBox).Editable = True Then
                If CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length > 0 _
                AndAlso Not CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length.ToString IsNot Nothing Then
                    If Not New Regex("^[a-zA-Z\s]*$").IsMatch(ctrl.Text) Then
                        ErrProv.SetError(ctrl, "Value may only contain letters and spaces.")
                        WhitespaceLettersOnly = WhitespaceLettersOnly Or True
                    ElseIf Not CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length = 0 Then
                        ErrProv.SetError(ctrl, "You must supply a value.")
                        WhitespaceLettersOnly = WhitespaceLettersOnly Or True
                    Else
                        ErrProv.SetError(ctrl, "")
                        WhitespaceLettersOnly = WhitespaceLettersOnly Or False
                    End If
                End If
            End If
        End If
 
        Return WhitespaceLettersOnly
    End Function

Come to think about it, a function won't be the best option here. Maybe a Public Sub because it'll be used to check as the end-user types.

This is what I have now. The only thing is, it's not showing the ErrorProvider regardless of situation.

vb Code:

Public Sub WhiteSpaceLettersOnly(ByVal ctrl As Elegant.Ui.Control)
        bCheckFailed = True
 
        Dim ErrProv As New ErrorProvider
 
        If TypeOf ctrl Is Elegant.Ui.TextBox Then
            'Something is present but not just spaces.
            If CType(ctrl, Elegant.Ui.TextBox).TextLength > 0 _
            AndAlso Not CType(ctrl, Elegant.Ui.TextBox).TextLength.ToString IsNot Nothing Then
                'Check for a-z, A-Z and whitespace (\s).
                'Make sure only upper case, lower case and spaces allowed.
                'No spaces allowed without the existence of letters.
                If Not New Regex("^[azA-Z\s]*$").IsMatch(ctrl.Text) Then
                    ErrProv.SetError(ctrl, "Value may only contain letters and spaces.")
                    bCheckFailed = bCheckFailed Or True
                    'No text entered.
                ElseIf CType(ctrl, Elegant.Ui.TextBox).TextLength = 0 Then
                    ErrProv.SetError(ctrl, "You must supply a value.")
                    bCheckFailed = bCheckFailed Or True
                Else
                    ErrProv.SetError(ctrl, "")
                    bCheckFailed = bCheckFailed Or False
                End If
            End If
        ElseIf TypeOf ctrl Is Elegant.Ui.ComboBox Then
            'ComboBox is editable.
            If CType(ctrl, Elegant.Ui.ComboBox).Editable = True Then
                'Something is present but not just spaces.
                If CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length > 0 _
                AndAlso Not CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length.ToString IsNot Nothing Then
                    'Check for a-z, A-Z and whitespace (\s).
                    'Make sure only upper case, lower case and spaces allowed.
                    'No spaces allowed without the existence of letters.
                    If Not New Regex("^[a-zA-Z\s]*$").IsMatch(ctrl.Text) Then
                        ErrProv.SetError(ctrl, "Value may only contain letters and spaces.")
                        bCheckFailed = bCheckFailed Or True
                        'No text entered.
                    ElseIf Not CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length = 0 Then
                        ErrProv.SetError(ctrl, "You must supply a value.")
                        bCheckFailed = bCheckFailed Or True
                    Else
                        ErrProv.SetError(ctrl, "")
                        bCheckFailed = bCheckFailed Or False
                    End If
                End If
            End If
        End If
    End Sub

OK, I am getting somewhere. I am able to get it to work when the end user only types in spaces or numbers. But the error doesn't go away when I type in something valid. Time to go through my logic. Would love a second pair of eyes. Been coding straight for nine hours now. :-)

vb Code:

Public Sub WhiteSpaceLettersOnly(ByVal ctrl As Elegant.Ui.Control)
        bCheckFailed = True
 
        Dim ErrProv As New ErrorProvider
 
        If TypeOf ctrl Is Elegant.Ui.TextBox Then
            'Something is present but not just spaces.
            If CType(ctrl, Elegant.Ui.TextBox).TextLength > 0 _
            AndAlso Not CType(ctrl, Elegant.Ui.TextBox).TextLength.ToString IsNot Nothing Then
                'Check for a-z, A-Z and whitespace (\s).
                'Make sure only upper case, lower case and spaces allowed.
                'No spaces allowed without the existence of letters.
                If Not New Regex("^[azA-Z\s]*$").IsMatch(ctrl.Text) Then
                    ErrProv.SetError(ctrl, "Value may only contain letters and spaces.")
                    bCheckFailed = bCheckFailed Or True
                    'No text entered.
                ElseIf CType(ctrl, Elegant.Ui.TextBox).TextLength = 0 Then
                    ErrProv.SetError(ctrl, "You must supply a value.")
                    bCheckFailed = bCheckFailed Or True
                Else
                    ErrProv.SetError(ctrl, "")
                    bCheckFailed = bCheckFailed Or False
                End If
            Else
                'Check for a-z, A-Z and whitespace (\s).
                'Make sure only upper case, lower case and spaces allowed.
                'No spaces allowed without the existence of letters.
                If Not New Regex("^[a-zA-Z\s]*$").IsMatch(ctrl.Text) Then
                    ErrProv.SetError(ctrl, "Value may only contain letters and spaces.")
                    bCheckFailed = bCheckFailed Or True
                    'No text entered.
                ElseIf Not CType(ctrl, Elegant.Ui.TextBox).TextLength = 0 Then
                    ErrProv.SetError(ctrl, "You must supply a value.")
                    bCheckFailed = bCheckFailed Or True
                Else
                    ErrProv.SetError(ctrl, "")
                    bCheckFailed = bCheckFailed Or False
                End If
            End If
        ElseIf TypeOf ctrl Is Elegant.Ui.ComboBox Then
            'ComboBox is editable.
            If CType(ctrl, Elegant.Ui.ComboBox).Editable = True Then
                'Something is present but not just spaces.
                If CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length > 0 _
                AndAlso Not CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length.ToString IsNot Nothing Then
                    'Check for a-z, A-Z and whitespace (\s).
                    'Make sure only upper case, lower case and spaces allowed.
                    'No spaces allowed without the existence of letters.
                    If Not New Regex("^[a-zA-Z\s]*$").IsMatch(ctrl.Text) Then
                        ErrProv.SetError(ctrl, "Value may only contain letters and spaces.")
                        bCheckFailed = bCheckFailed Or True
                        'No text entered.
                    ElseIf Not CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length = 0 Then
                        ErrProv.SetError(ctrl, "You must supply a value.")
                        bCheckFailed = bCheckFailed Or True
                    Else
                        ErrProv.SetError(ctrl, "")
                        bCheckFailed = bCheckFailed Or False
                    End If
                End If
            End If
        Else
            'Check for a-z, A-Z and whitespace (\s).
            'Make sure only upper case, lower case and spaces allowed.
            'No spaces allowed without the existence of letters.
            If Not New Regex("^[a-zA-Z\s]*$").IsMatch(ctrl.Text) Then
                ErrProv.SetError(ctrl, "Value may only contain letters and spaces.")
                bCheckFailed = bCheckFailed Or True
                'No text entered.
            ElseIf Not CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length = 0 Then
                ErrProv.SetError(ctrl, "You must supply a value.")
                bCheckFailed = bCheckFailed Or True
            Else
                ErrProv.SetError(ctrl, "")
                bCheckFailed = bCheckFailed Or False
            End If
        End If
    End Sub

OK, I tried the following and still not working. Same as prior post.

vb Code:

Public Sub WhiteSpaceLettersOnly(ByVal ctrl As Elegant.Ui.Control)
        bCheckFailed = True
 
        Dim ErrProv As New ErrorProvider
 
        If TypeOf ctrl Is Elegant.Ui.TextBox Then
            'Something is present but not just spaces.
            If CType(ctrl, Elegant.Ui.TextBox).TextLength > 0 _
            AndAlso Not CType(ctrl, Elegant.Ui.TextBox).TextLength.ToString IsNot Nothing Then
                'Check for a-z, A-Z and whitespace (\s).
                'Make sure only upper case, lower case and spaces allowed.
                'No spaces allowed without the existence of letters.
                If Not New Regex("^[azA-Z\s]*$").IsMatch(ctrl.Text) Then
                    ErrProv.SetError(ctrl, "Value may only contain letters and spaces.")
                    bCheckFailed = bCheckFailed Or True
                Else
                    ErrProv.SetError(ctrl, "")
                    bCheckFailed = bCheckFailed Or False
                End If
            ElseIf Not CType(ctrl, Elegant.Ui.TextBox).TextLength = 0 Then
                ErrProv.SetError(ctrl, "You must supply a value.")
                bCheckFailed = bCheckFailed Or True
            Else
                ErrProv.SetError(ctrl, "")
                bCheckFailed = bCheckFailed Or False
            End If
        ElseIf TypeOf ctrl Is Elegant.Ui.ComboBox Then
            'ComboBox is editable.
            If CType(ctrl, Elegant.Ui.ComboBox).Editable = True Then
                'Something is present but not just spaces.
                If CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length > 0 _
                AndAlso Not CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length.ToString IsNot Nothing Then
                    'Check for a-z, A-Z and whitespace (\s).
                    'Make sure only upper case, lower case and spaces allowed.
                    'No spaces allowed without the existence of letters.
                    If Not New Regex("^[a-zA-Z\s]*$").IsMatch(ctrl.Text) Then
                        ErrProv.SetError(ctrl, "Value may only contain letters and spaces.")
                        bCheckFailed = bCheckFailed Or True
                    Else
                        ErrProv.SetError(ctrl, "")
                        bCheckFailed = bCheckFailed Or False
                    End If
                ElseIf Not CType(ctrl, Elegant.Ui.ComboBox).Text.Trim.Length = 0 Then
                    ErrProv.SetError(ctrl, "You must supply a value.")
                    bCheckFailed = bCheckFailed Or True
                Else
                    ErrProv.SetError(ctrl, "")
                    bCheckFailed = bCheckFailed Or False
                End If
            End If
        End If
    End Sub

OK, still not working right. It's allowing numbers when it shouldn't be. I won't spam my thread, so I'll work on the issue and if I have trouble,I'll be back. This won't beat me! :-)

What I had in mind was something like this:

Code:

---

Function CheckForInput(ByVal strInput As String) As Boolean
    If Input Is Valid 'Perform any regex or other tests/comparisons/checks here
        Return True
    Else
        Return False
    End If
End Function

'This could be your keypress, lostfocus or any other control event
Private Sub Control_Event(Sender As Object, E As EventArgs)
    If TypeOf Sender Is Elegant.UI.Control Then
        If Not CheckForInput(Sender.Text) Then
            'Raise error for invalid input
        End If
    End If
End Sub

---

Now, you can test the CheckForInput function separately to see if it correctly returns True for valid inputs and False for any invalid inputs (you could check it manually or through unit testing apps such as Microsoft's unit testing or nUnit). This way you can finetune the CheckForInput function to suit your exact needs.

CheckForInput function should take the text to be validated and return a True/False value based on the validation results. It should not be knowing which control types to check and what to do if the text is not validated. This is part of UI interaction and should be handled in the respective control events.

.