Mandatory CheckBox

Problem: The RequiredFieldValidator doesn't allow you to enforce that a CheckBox in asp.net is checked/selected.

Solution: Best approach I could find was to simply use a CustomValidator (ideally with client and server side validation but server side would be sufficient). Example code is as follows:

ASPX PAGE:

ClientValidationFunction="ValidateTermsAndConditionsAgreement"

OnServerValidate="ValidateTermsAndConditionsAgreement"

runat="server"

Text=" You must agree to the terms and conditions before entering. "

ValidationGroup="vgEntryDetails"

CssClass="error"

Display="Dynamic">

CODE BEHIND:

Since I was actually optionally displaying my checkbox I actually added the validation script optionally in Page_Load (note, it needs to be done regardless of whether Page_Load is being called as part of a postback or not otherwise if there is a postback before you click submit the javascript you've injected via the code behind won't be there and hence the client side validation will not work).

//Script to use as part of the page validation

if (!Page.ClientScript.IsClientScriptBlockRegistered(this.GetType(), "TermsAndConditionsScript"))

{

string scriptText = " function ValidateTermsAndConditionsAgreement(sender, args){" +

" if (document.getElementById('" + chkAgreeToTermsAndConditions.ClientID + "').checked){" +

" args.IsValid = true;" +

" }" +

" else {" +

" args.IsValid = false;" +

" }" +

" return;" +

"}";

Page.ClientScript.RegisterClientScriptBlock(this.GetType(),

"TermsAndConditionsScript", scriptText, true);

}

...and the server side validation

///

/// Validate that the terms and conditions have been agreed to if they exist

///

///

///

protected void ValidateTermsAndConditionsAgreement(object source, ServerValidateEventArgs args)

{

if (chkAgreeToTermsAndConditions.Checked == false)

{

args.IsValid = false;

}

}

...and finally don't forget to check IsValid in your method called by the submit button.

protected void btnSubmitEntry_Click(object sender, EventArgs e)

{

//Is valid check is required because we have a CustomerValidator control

//for the terms and conditions checkbox - if it's not valid we don't want to proceed and the error will be

//displayed.

if (Page.IsValid)

{

//Save competition entry

....