System.InvalidCastException: Conversion from string "" to type 'Long' is not valid. ---> System.FormatException: Input string was not in a correct format. at Microsoft.VisualBasic.CompilerServices.Conversions.ParseDecimal(String Value, NumberFormatInfo NumberFormat) at Microsoft.VisualBasic.CompilerServices.Conversions.ToLong(String Value) --- End of inner exception stack trace --- at Microsoft.VisualBasic.CompilerServices.Conversions.ToLong(String Value) at Microsoft.VisualBasic.CompilerServices.Conversions.ToLong(Object Value) at addmin_web.Comp_Usergroup_Regform.MakeFormChangeUSerdata(DataRow& drkomp, HybridDictionary& ap, HttpContext& httpContext, Read_Data& dbdata, HtmlControl& divreturn, HybridDictionary& ko) at addmin_web.Comp_UsergroupMain.MakeChangeUSerdataNonPost(DataRow& drkomp, NameValueCollection collAbs, Read_Data& dbdata) at addmin_web.Comp_UsergroupMain.PrintChangeUSerdata(DataRow& drkomp, NameValueCollection collAbs, Read_Data& dbdata) at addmin_web.Comp_UsergroupMain.PrintComponent(HtmlControl& td_sp, Read_Data& dbdata, NameValueCollection& collAbs, DataRow& drKomp) at addmin_web.paragraph_main.ComponentSelect(DataRow& drkomp, NameValueCollection& collabs, Read_Data& dbdata, HtmlGenericControl& div_sp) at addmin_web.paragraph_main.preComponentSelect(DataRow& drkomp, NameValueCollection& collabs, Read_Data& dbdata, HtmlGenericControl& div_sp, Int32& intLastReihe) at addmin_web.paragraph_main.Component_Loop(DataRow& drAbsatz, NameValueCollection& collAbs, Read_Data dbdata, HtmlGenericControl& div_sp)