Thread: Validation Function / Class

Does anyone use a standard class or function to provide validation in their apps?

In a previous app I wrote a validation function that took parameters of the value to validate, the max length it could be, whether it was required and a code to use a specific regex pattern to validate.

So, I could reuse this function on all form controls to validate the content. My preference is to have an "error display box" on the page that is used to display any validation errors on a sequential, singular basis. For example, suppose you had the following page:-

Code:

<asp:panel id="pnlError" runat="server">
</asp:panel>
<asp:textbox id="textbox1" runat="server" /> //This element is required
<asp:textbox id="textbox2" runat="server" /> //This element can only accept [a-z]

If textbox1 is left blank and textbox2 contains 123456, all I want to show is that texbox1 must be completed. I think it makes it more confusing for the user if they have a whole list of validation errors to complete.

I don't know if this is a particularly good or acceptable method of validating?

I know .NET provides validation controls. Does anyone just use these or do you have a standard function that you reuse in apps?

What method(s) do you guys tend to use?

btw, I know about providing client side and server side validation. I'm referring just to server side here.

Generally i use different code for validation on each page.

If there is some special validation like email, integer, etc...; i make their functions separately and just use them on each page.

Originally Posted by micky

Generally i use different code for validation on each page.

If there is some special validation like email, integer, etc...; i make their functions separately and just use them on each page.

Do you use the built in validation controls or do you write specific validation functions for each control you have?

Could you just do a quick, simple example?

Sometimes i use the built in ones like IsDate, like

Code:

If strDate = String.Empty Or Not IsDate(strDate) Then
        sText = "  Date!"
End If

Sometimes i use functions, like for checking float values

Code:

If Regex.IsMatch(strLongitude, CGlobal.CheckFloat) = False Then
        sText = "  Longitude is in Wrong Format!"
End If

Code for CGlobal.CheckFloat

Code:

Public Shared Function CheckFloat() As String
    'Decimals value
    CheckFloat = "^(-)?[0-9]+(\.[0-9]{1,10})?$"
End Function

I only use the validation controls. I have a lot of fun with the RegularExpressionValidator.

Originally Posted by jmurrayhead

I only use the validation controls. I have a lot of fun with the RegularExpressionValidator.

Could you give an example J?

Also, what about if you have a required field and one that should only contain [a-z], for example?

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.

But you would still need server side validation...... right??

Originally Posted by micky

But you would still need server side validation...... right??

Validation controls perform both client-side and server-side validation. All you need to do is add:

Code:

If Page.IsValid Then
    ' Place code here
End If

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

Lot of code would have been saved by me