已解决
object  missing = Missing.Value;   
                 ExcelObj.Run("aa",missing,missing,   
                        missing,missing,missing,missing,   
                        missing,missing,missing,   missing,   
                        missing,missing,missing,missing,   
                        missing,missing,   missing,missing,   
                        missing,missing,missing,missing,   
                        missing,missing,missing,missing,   
                        missing,   missing,missing,missing);