Server Error in '/' Application.
'~/Search.aspx?pageidx=1&Id=:' is not a valid virtual path.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Web.HttpException: '~/Search.aspx?pageidx=1&Id=:' is not a valid virtual path.
Understand that in asp.net, virtual path in the URL with colon (:) is not allowed. To solve this problem, i replace the colon (:) with ASCII value for colon &#58; (please check http://www.asciitable.com/) and HttpUtility.UrlEncode on the search key before pass into search.aspx as querystring.
In Search.aspx.cs, do HttpUtility.UrlDecode and pass to DB for searching purposes. Problem solve. Bear in mind that you might need to disable the ValidateRequest (ValidateRequest="false") which may open for dangerous hijack/request.