The Mistery of Windows Form Validation - How do you really validate windows forms?

NovicePGM2011 · March 20th, 2011, 12:56 AM

I have a windows form I need to validate.

Example: I have several text boxes, check boxes and radio buttons I need to validate. I need to validate the text boxes for text(strings) only, no characters. How do I validate multiple text boxes without rewriting the codes.

Finally how do I validate radio buttons and check boxes?

Here is what I have written so far. This idea of validation using conditions is based on standard programming.

However, my code does not work properly.

1. I have to provide a loop so the code continue to fire error messages until the user enter a valid data. Right now if the user enter a number, the form fires an error message, if the user deletes the numbers, enters text and re-enters number the form does not validate. That's because the code must have a loop. How do I loop this code, if there a better way to validate?

2. How do I use what I have already written on multiple form controls with out writing this entire code for every form control?

Here is what I have writing.

Code:

Public Class validDataForm

    Private Sub validDataForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub btnDataSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDataSubmit.Click
        Dim invalidUserData As String
        invalidUserData = "!, @, #, $, %, ^, &, *, (, ), _, +, [, {, ], }, \, =, |, :, ;,>, <, ?, /, .,"

        If IsNumeric(txtDataEntry.Text) Then
            lblErrorDisplay.Text = "Invalid Name!"

        ElseIf txtDataEntry.Text = String.Empty Then
            lblErrorDisplay.Text = "Full Name Required!"

        ElseIf txtDataEntry.Text.Length > 25 Or txtDataEntry.Text.Length < 2 Then
            lblErrorDisplay.Text = "Valid Name Required!"

        ElseIf txtDataEntry.Text = String.Empty Then
            lblErrorDisplay.Text = "Name Required!"

        ElseIf txtDataEntry.Text = invalidUserData Then
            lblErrorDisplay.Text = "Valid Name Required!"

        Else
            lblErrorDisplay.Hide()

        End If

    End Sub

    Private Sub lblUserName_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lblUserName.Click

    End Sub

    Private Sub txtDataEntry_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtDataEntry.TextChanged

    End Sub
End Class

Thanks everyone!

NovicePGM

GeneBuchite · March 20th, 2011, 07:56 AM

I would place my validation code in a Sub. then call the sub each time you leave the individual field. ie...

Code:

 
    Private Sub btnDataSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDataSubmit.Click
       

       If RBSexF.Checked = False And rbSexM.Checked = False Then                  ' Validate Radio Buttons
            MsgBox("You Must Select Either MAle Or Female")

            Exit Sub
        End If

        Dim invalidUserData As String


        invalidUserData = "!, @, #, $, %, ^, &, *, (, ), _, +, [, {, ], }, \, =, |, :, ;,>, <, ?, /, .,"

        If IsNumeric(txtDataEntry.Text) Then
            lblErrorDisplay.Text = "Invalid Name!"

        ElseIf txtDataEntry.Text = String.Empty Then
            lblErrorDisplay.Text = "Full Name Required!"

        ElseIf txtDataEntry.Text.Length > 25 Or txtDataEntry.Text.Length < 2 Then
            lblErrorDisplay.Text = "Valid Name Required!"

        ElseIf txtDataEntry.Text = String.Empty Then
            lblErrorDisplay.Text = "Name Required!"

        ElseIf txtDataEntry.Text = invalidUserData Then
            lblErrorDisplay.Text = "Valid Name Required!"

        Else
            lblErrorDisplay.Text = "All Ok"


        End If

    End Sub



    Private Sub txtDataEntry_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtDataEntry.TextChanged

    End Sub



    Private Sub txtDataEntry_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles txtDataEntry.Validating
        ValidateEntries(txtDataEntry.Text.ToString, "Name")

    End Sub
    Private Sub ValidateEntries(ByVal txt As String, ByVal lbl As String)
        MsgBox(txt)
        Dim invalidUserData As String
        invalidUserData = "!, @, #, $, %, ^, &, *, (, ), _, +, [, {, ], }, \, =, |, :, ;,>, <, ?, /, .,"

        If IsNumeric(txt) Then
            lblErrorDisplay.Text = "Invalid " & lbl & "!"

        ElseIf txt = String.Empty Then
            lblErrorDisplay.Text = lbl & " Required!"

        ElseIf txt.Length > 25 Or txt.Length < 2 Then
            lblErrorDisplay.Text = "Valid " & lbl & " Required! Must be at least Longer than 2 and less than 25!"


        ElseIf txt = invalidUserData Then
            lblErrorDisplay.Text = "Valid " & lbl & " Required!"

        Else
            lblErrorDisplay.Text = "All Ok"


        End If
    End Sub

    Private Sub TextBox1_Leave(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.Leave
        ValidateEntries(TextBox1.Text, "Address")
    End Sub

To Demonstrate I added another TextBox "TextBox1" To The Form

You will need to write new codes for each field that uses different rules.

I Am not sure of your Question of Validating Radio Buttons MAybe something Like This Would Help...
Add 2 Radio Buttons. NAme Them rbSexM & THen The btnValidate Will Validate The Radio Buttons.

NovicePGM2011 · March 20th, 2011, 11:04 AM

Quote:

Originally Posted by GeneBuchite

I would place my validation code in a Sub. then call the sub each time you leave the individual field. ie...

Code:

 
    Private Sub btnDataSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDataSubmit.Click
       

       If RBSexF.Checked = False And rbSexM.Checked = False Then                  ' Validate Radio Buttons
            MsgBox("You Must Select Either MAle Or Female")

            Exit Sub
        End If

        Dim invalidUserData As String


        invalidUserData = "!, @, #, $, %, ^, &, *, (, ), _, +, [, {, ], }, \, =, |, :, ;,>, <, ?, /, .,"

        If IsNumeric(txtDataEntry.Text) Then
            lblErrorDisplay.Text = "Invalid Name!"

        ElseIf txtDataEntry.Text = String.Empty Then
            lblErrorDisplay.Text = "Full Name Required!"

        ElseIf txtDataEntry.Text.Length > 25 Or txtDataEntry.Text.Length < 2 Then
            lblErrorDisplay.Text = "Valid Name Required!"

        ElseIf txtDataEntry.Text = String.Empty Then
            lblErrorDisplay.Text = "Name Required!"

        ElseIf txtDataEntry.Text = invalidUserData Then
            lblErrorDisplay.Text = "Valid Name Required!"

        Else
            lblErrorDisplay.Text = "All Ok"


        End If

    End Sub



    Private Sub txtDataEntry_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtDataEntry.TextChanged

    End Sub



    Private Sub txtDataEntry_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles txtDataEntry.Validating
        ValidateEntries(txtDataEntry.Text.ToString, "Name")

    End Sub
    Private Sub ValidateEntries(ByVal txt As String, ByVal lbl As String)
        MsgBox(txt)
        Dim invalidUserData As String
        invalidUserData = "!, @, #, $, %, ^, &, *, (, ), _, +, [, {, ], }, \, =, |, :, ;,>, <, ?, /, .,"

        If IsNumeric(txt) Then
            lblErrorDisplay.Text = "Invalid " & lbl & "!"

        ElseIf txt = String.Empty Then
            lblErrorDisplay.Text = lbl & " Required!"

        ElseIf txt.Length > 25 Or txt.Length < 2 Then
            lblErrorDisplay.Text = "Valid " & lbl & " Required! Must be at least Longer than 2 and less than 25!"


        ElseIf txt = invalidUserData Then
            lblErrorDisplay.Text = "Valid " & lbl & " Required!"

        Else
            lblErrorDisplay.Text = "All Ok"


        End If
    End Sub

    Private Sub TextBox1_Leave(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.Leave
        ValidateEntries(TextBox1.Text, "Address")
    End Sub

To Demonstrate I added another TextBox "TextBox1" To The Form

You will need to write new codes for each field that uses different rules.

I Am not sure of your Question of Validating Radio Buttons MAybe something Like This Would Help...
Add 2 Radio Buttons. NAme Them rbSexM & THen The btnValidate Will Validate The Radio Buttons.

Thanks for your reply, I will work with your example and let you know how things turned out.

Thanks again a lot!!

NovicePGM