Invalid postback or callback argument. Event validation is enabled using

Sys.WebForms.PageRequestManagerServerErrorException: Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation

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ScriptManager may not find the control when binding is done in Page_Load instead bining the data to control (like dataset) in Page_PreRender will solve the issue.