Thread: Validation Function / Class

Originally Posted by jmurrayhead

Code:

<asp:TextBox ID="TextBox1" runat="server" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"
       ControlToValidate="TextBox1"
       Display="Dynamic"
       ErrorMessage="TextBox1 is required" 
       Text="*" />
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server"
       ControlToValidate="TextBox1"
       Display="Dynamic"
       ErrorMessage="TextBox1 contains invalid characters"
       Text="*"
       ValidationExpression="^[a-zA-Z]$" />

This requires the use of the ValidationSummary control to display all error messages in a box together.

So, in the case that textbox1 was blank, just the TextBox1 is required text would show and in the case someone entered 12345, just TextBox1 contains invalid characters would show?

And, in the example I gave, you could change <asp: panel> control to ValidationSummary and all error messages for all validation controls would show here?

Originally Posted by micky

Nice.
So then server side validation can be by-passed!!

Lot of code would have been saved by me

m, I think using validation controls is server side validation. They are .NET controls, after all.

Originally Posted by micky

Nice.
So then server side validation can be by-passed!!

Lot of code would have been saved by me

Indeed

Originally Posted by richyrich

So, in the case that textbox1 was blank, just the TextBox1 is required text would show and in the case someone entered 12345, just TextBox1 contains invalid characters would show?

And, in the example I gave, you could change <asp: panel> control to ValidationSummary and all error messages for all validation controls would show here?

Yes, Yes and Yes!!

Originally Posted by richyrich

m, I think using validation controls is server side validation. They are .NET controls, after all.

As long as you perform the validation check using Page.IsValid as I have shown

Originally Posted by richyrich

So, in the case that textbox1 was blank, just the TextBox1 is required text would show and in the case someone entered 12345, just TextBox1 contains invalid characters would show?

Yes, you'll need separate required validators and regular validator for 1 control.
And each for other controls that you want to validate.

Originally Posted by richyrich

And, in the example I gave, you could change <asp: panel> control to ValidationSummary and all error messages for all validation controls would show here?

ValidationSummary can show a message box or also can post the error like on a label

Originally Posted by richyrich

m, I think using validation controls is server side validation. They are .NET controls, after all.

I think they use javascript to fire, so if the js is disables, then they might not fire and hence the need for server side validation.

Originally Posted by micky

I think they use javascript to fire, so if the js is disables, then they might not fire and hence the need for server side validation.

They use JavaScript to fire the client-side validation, but using Page.IsValid on the server will fire the server-side validation that is defined by each validation control:

Code:

Protected Sub btnSave_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSave.Click
    If Page.IsValid Then
        ' Code to save the record here
    End If
End Sub

thats good to know J

Would it be able to handle the scenario where you might have two submit controls where one submits the form in full and the other only checks a few of the textboxes?

Say, for example, you have a form that has name, date of birth and address details and a button that prepopulates a series of address textboxes if the user just enters a postcode / zipcode.

So, you want to validate the postcode, zipcode is valid when prepopulating the address, but you don't want to validate the name and date of birth fields until the full form is submitted.

How would you handle this using validation controls? I presume if you used Page.IsValid in the GetAddress function, it would pick up the name and date of birth validations as well.

Validation controls have a property called "ValidationGroup" where you would set the name (i.e. ValidationGroup="SaveRecord"). You would have to assign the ValidationGroup property of the individual buttons, using the same name as the form items they are to validate.

Just in case anyone comes across this thread for information, I had to change the validation expression to below:-

Code:

                    <asp:RegularExpressionValidator ID="revForename" runat="server" ControlToValidate="txtForename"
                        ErrorMessage="The forename you entered contains invalid characters" ValidationExpression="^[a-zA-Z ]+$"
                        Display="None" EnableClientScript="true" />

Otherwise it wouldn't accept the text I entered.