Invalid postback or callback argument error?

Question

I have two dropdownlists and I am filling one based on the other using javascript. In my javascript code I am calling for a webservice and with the results returned I fill t

Answer 1

My problem was solved when cancel event at end of grid event at server side.

protected void grdEducation_RowEditing(object sender, GridViewEditEventArgs e)
{
  // do your processing ... 

  // at end     
  e.Cancel = true;
}

Answer 2

I got same Error when i got one of my clients project. It is related to the web.config file. Simply Paste the below code under appSettings in config file.

<add key="PageInspector:ServerCodeMappingSupport" value="Disabled" />

Answer 3

If you want to modify generated controls from client side, you have to disable eventvalidation or register all possible values with RegisterForEventValidation. It's well explained here. It's because the data sent to the client and received after by the server differs.

edit:also responded here.