Recently, I was facing a problem where if there was a validation error, and if I changed
the state of checkbox it won't postback on first attempt. But when I uncheck and check again , it postbacks on second attempt...this is some quirky behaviour in .ASP.Net platform.
The solution was to reset Page_BlockSubmit flag to false and it works fine.
The following explanation is from
http://lionsden.co.il/codeden/?p=137&cpage=1#comment-143
Submit button on
the page is a member of vgMain, so automatically it will only run
the validation on that group. A solution is needed that will run validation on multiple groups and block
the postback if needed.
Solution
Include
the following function on
the page:
function DoValidation()
{
//validate
the primary group
var validated = Page_ClientValidate('vgPrimary ');
//if it is valid
if (validated)
{
//valid
the main group
validated = Page_ClientValidate('vgMain');
}
//remove
the flag to block
the submit if it was raised
Page_BlockSubmit = false;
//return
the results
return validated;
}
Call
the above function from
the submit button’s OnClientClick event.
<asp:Button runat="server" ID="btnSubmit" CausesValidation="true"
ValidationGroup="vgMain" Text="Next" OnClick="btnSubmit_Click"
OnClientClick="return DoValidation();" />
What is Page_BlockSubmit
When
the user clicks on a button causing a full post back, after running Page_ClientValidate ASP.NET runs another built in function ValidatorCommonOnSubmit. Within Page_ClientValidate, Page_BlockSubmit is set based on
the validation.
The postback is then blocked in ValidatorCommonOnSubmit if Page_BlockSubmit is true. No matter what, at
the end of
the function Page_BlockSubmit is always reset back to false.
If a page does a partial postback without running any validation and Page_BlockSubmit has not been reset to false,
the partial postback will be blocked. In essence
the above function, RunValidation, acts similar to ValidatorCommonOnSubmit. It runs
the validation and then returns false to block
the postback if needed. Since
the built in postback is never run, we need to reset Page_BlockSubmit manually before returning
the validation result.
