Serialization problem in StoredProcedure

Dear All,
I want to store the result of the stored procedure in the viewstate. I tried this code snippets, But error thrown that Stored procedure should be serialized.
Code Snippets:
private List<USP_SelectIssueLogByIDResult> VState_USP_SelectIssueLogByIDResult
        { get
  {
                List<USP_SelectIssueLogByIDResult> s = null;
                s = List<USP_SelectIssueLogByIDResult>)ViewState["VState_USP_SelectIssueLogByIDResult"];
                return s;
            }
           set
   &n ...