CODEWITHSUNDEEP
asp.netvb.netvalidation
pmlevere
pmlevere

Reputation: 77

Custom validation in VB.net requiring user to sum textboxes to 100

I have a VB web app built in .Net 4.0 and am trying to add some custom validation.

I have 6 asp textboxes that I want to require the user to sum to 100. All 6 fields have required field and required expression validators that require the user to enter a number between 0.0 and 100.0, but I need additional validation to sum to 100.0. So again, 6 textboxes with numbers only that allow whole numbers or single decimal numbers.

I'm a relatively new programmer, what's the best way to do this:

Textbox1 + Textbox2 + Textbox3 + Textbox4 + Textbox5 + Textbox 6 = 100.0 (if not, prompt user with values don't equal 100.0 and don't allow button click until the values are fixed.

Thanks for your help!

Upvotes: 1

Views: 1531

Answers (1)

Tim Schmelter
Tim Schmelter

Reputation: 460108

Use a CustomValidator which is the only validator that allows to omit the ControlToValidate:

<asp:CustomValidator runat="server" ID="CustomValidator1"
   Text="The sum must be 100" 
   ClientValidationFunction="clientValidate" 
   EnableClientScript="True"
   Display="Static">
</asp:CustomValidator>

The ServerValidate:

Protected Sub ServerValidation(source As Object, args As ServerValidateEventArgs) Handles CustomValidator1.ServerValidate
    Dim val1 As Decimal
    Dim val2 As Decimal
    Dim val3 As Decimal
    Dim val4 As Decimal
    Dim val5 As Decimal
    If Decimal.TryParse(TextBox1.Text, val1) AndAlso _
       Decimal.TryParse(TextBox2.Text, val2) AndAlso _
       Decimal.TryParse(TextBox3.Text, val3) AndAlso _
       Decimal.TryParse(TextBox4.Text, val4) AndAlso _
       Decimal.TryParse(TextBox5.Text, val5) Then
        args.IsValid = val1 + val2 + val3 + val4 + val5 = 100
    Else
        args.IsValid = False
    End If
End Sub

You can also provide a client validation function. Therefore you need to find the references to the textboxes per javascript and then calculate the total value on clientside.

For example:

<script type="text/javascript" >
    function clientValidate(source, arguments) {
        var txt1 = document.getElementById('<%= TextBox1.ClientID %>');
        var txt2 = document.getElementById('<%= TextBox2.ClientID %>');
        var txt3 = document.getElementById('<%= TextBox3.ClientID %>');
        var txt4 = document.getElementById('<%= TextBox4.ClientID %>');
        var txt5 = document.getElementById('<%= TextBox5.ClientID %>');
        if(txt1 != null && txt2 != null && txt3 != null && txt4 != null && txt5 != null && txt1.value != "" && !isNaN(txt1.value) && txt2.value != "" && !isNaN(txt2.value) && txt3.value != "" && !isNaN(txt3.value) && txt4.value != "" && !isNaN(txt4.value) && txt5.value != "" && !isNaN(txt5.value))
        {
            var num1 = parseFloat(txt1.value);
            var num2 = parseFloat(txt2.value);
            var num3 = parseFloat(txt3.value);
            var num4 = parseFloat(txt4.value);
            var num5 = parseFloat(txt5.value);
            arguments.IsValid = num1 + num2 +num3 + num4 + num5 == 100;
        }
        else
            arguments.IsValid = false;
    }
</script>

Upvotes: 3

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