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.
