Strano errore: System.Web.UI.WebControls.EntityDataSourceView.Con vertWCProperty

[broggini.dav]

Ciao a tutti,
ho un detailView in insert mode che lavora con un EntityDatasource.
Nel DetailView ci sono diverse dropDownlist collegate ad altri eds (per le tabelle correlate).
Quando salvo, la pagina mi dà il suddetto errore.
Non so più dove sbattere la testa javascript:void(0);
potete aiutarmi?
GRAZIE MILLE


[NullReferenceException: Riferimento a un oggetto non impostato su un'istanza di oggetto.]
System.Web.UI.WebControls.EntityDataSourceView.Con vertWCProperty(IDictionary values, Dictionary`2 convertedValues, List`1 visitedProperties, PropertyDescriptor pd, ParameterCollection referenceParameters, Dictionary`2& exceptions) +35
System.Web.UI.WebControls.EntityDataSourceView.Con vertProperties(IDictionary values, PropertyDescriptorCollection propertyDescriptors, ParameterCollection referenceParameters) +216
System.Web.UI.WebControls.EntityDataSourceView.Cre ateEntityForInsert(EntityDataSourceWrapper entityWrapper, IDictionary values, ParameterCollection insertParameters) +49
System.Web.UI.WebControls.EntityDataSourceView.Exe cuteInsert(IDictionary values) +239
System.Web.UI.DataSourceView.Insert(IDictionary values, DataSourceViewOperationCallback callback) +86
System.Web.UI.WebControls.DetailsView.HandleInsert (String commandArg, Boolean causesValidation) +274
System.Web.UI.WebControls.DetailsView.HandleEvent( EventArgs e, Boolean causesValidation, String validationGroup) +676
System.Web.UI.WebControls.DetailsView.OnBubbleEven t(Object source, EventArgs e) +95
System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +37
System.Web.UI.WebControls.DetailsViewRow.OnBubbleE vent(Object source, EventArgs e) +113
System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +37
System.Web.UI.WebControls.Button.OnCommand(Command EventArgs e) +118
System.Web.UI.WebControls.Button.RaisePostBackEven t(String eventArgument) +166
System.Web.UI.WebControls.Button.System.Web.UI.IPo stBackEventHandler.RaisePostBackEvent(String eventArgument) +10
System.Web.UI.Page.RaisePostBackEvent(IPostBackEve ntHandler sourceControl, String eventArgument) +13
System.Web.UI.Page.RaisePostBackEvent(NameValueCol lection postData) +36
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565

l'html è il seguente

<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="false" CodeFile="articoli.aspx.cs" Inherits="articoli" Debug="True" EnableViewState="True" Trace="True" %>

<%@ Register assembly="System.Web.Entity, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" namespace="System.Web.UI.WebControls" tagprefix="asp" %>

<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">




<asp:Panel ID="PanelRicerca" runat="server" CssClass="pannelloRicerca">
<asp:Label ID="Label3" runat="server" Text="codice"></asp:Label>
<asp:TextBox ID="TXTricercaNome" runat="server"></asp:TextBox>

<asp:Button ID="BTNricerca" runat="server" Text="Ricerca"
onclick="BTNricerca_Click" />
<asp:Button ID="BTNannullaRicerca" runat="server" Text="annulla ricerca"
onclick="BTNannullaRicerca_Click" />




</asp:Panel>
<asp:Label ID="lbl_errore" runat="server" Text="Label" Visible="False"></asp:Label>




<asp:GridView ID="GridView1" runat="server" AllowPaging="True"
AllowSorting="True" AutoGenerateColumns="False" DataKeyNames="articoliID"
DataSourceID="EDSArticoli" onrowdeleted="GridView1_RowDeleted"
onrowupdated="GridView1_RowUpdated">
<Columns>
<asp:BoundField DataField="articoliID" HeaderText="articoliID"
SortExpression="articoliID" ReadOnly="True" />
<asp:BoundField DataField="codice" HeaderText="codice"
SortExpression="codice" />
<asp:BoundField DataField="articoliDescrizione"
HeaderText="articoliDescrizione" SortExpression="articoliDescrizione" />
<asp:BoundField DataField="fornitori.fornitoriID"
HeaderText="fornitori.fornitoriID" SortExpression="fornitori.fornitoriID" />
<asp:BoundField DataField="marche.marcheID" HeaderText="marche.marcheID"
SortExpression="marche.marcheID" />
<asp:BoundField DataField="modelli.modelliID" HeaderText="modelli.modelliID"
SortExpression="modelli.modelliID" />
<asp:BoundField DataField="tipologie.tipologieID"
HeaderText="tipologie.tipologieID" SortExpression="tipologie.tipologieID" />
</Columns>
</asp:GridView>
<asp:EntityDataSource ID="EDSArticoli" runat="server"
ConnectionString="name=dbmagaEntities" DefaultContainerName="dbmagaEntities"
EnableDelete="True" EnableInsert="True" EnableUpdate="True"
EntitySetName="articoli" Include="fornitori, marche, modelli, tipologie"
AutoGenerateWhereClause="True">
</asp:EntityDataSource>





<asp:Button ID="BTNnuovo" runat="server" onclick="BTNnuovo_Click"
Text="nuovo articolo" />



<aspetailsView ID="DetailsView1" runat="server" Height="50px" Width="125px"
AutoGenerateRows="False" DataKeyNames="articoliID" DataSourceID="EDSArticoli"
DefaultMode="Insert" oniteminserted="DetailsView1_ItemInserted"
oniteminserting="DetailsView1_ItemInserting">
<Fields>
<asp:BoundField DataField="articoliID" HeaderText="articoliID" ReadOnly="True"
SortExpression="articoliID" Visible="False" />
<asp:BoundField DataField="codice" HeaderText="codice"
SortExpression="codice" />
<asp:BoundField DataField="articoliDescrizione"
HeaderText="articoliDescrizione" SortExpression="articoliDescrizione" />
<asp:TemplateField HeaderText="fornitori.fornitoriID"
SortExpression="fornitori.fornitoriID" ConvertEmptyStringToNull="true">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server"
Text='<%# Bind("[fornitori.fornitoriID]") %>'></asp:TextBox>
</EditItemTemplate>
<InsertItemTemplate>
<aspropDownList ID="DropDownList1" runat="server" DataSourceID="EDSfornitori"
DataTextField="fornitoriNome" DataValueField="fornitoriID"
SelectedValue='<%# Bind("fornitori.fornitoriNome") %>'>
</aspropDownList>
</InsertItemTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server"
Text='<%# Bind("[fornitori.fornitoriID]") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="marche.marcheID"
SortExpression="marche.marcheID" ConvertEmptyStringToNull="true">
<EditItemTemplate>
<asp:TextBox ID="TextBox2" runat="server"
Text='<%# Bind("[marche.marcheID]") %>'></asp:TextBox>
</EditItemTemplate>
<InsertItemTemplate>
<aspropDownList ID="DropDownList2" runat="server" DataSourceID="EDSmarche"
DataTextField="marcheNome" DataValueField="marcheID"
SelectedValue='<%# Bind("marche.marcheID") %>'>
</aspropDownList>
</InsertItemTemplate>
<ItemTemplate>
<asp:Label ID="Label2" runat="server" Text='<%# Bind("[marche.marcheID]") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="modelli.modelliID"
SortExpression="modelli.modelliID" ConvertEmptyStringToNull="true">
<EditItemTemplate>
<asp:TextBox ID="TextBox3" runat="server"
Text='<%# Bind("[modelli.modelliID]") %>'></asp:TextBox>
</EditItemTemplate>
<InsertItemTemplate>
<aspropDownList ID="DropDownList3" runat="server" DataSourceID="EDSmodelli"
DataTextField="modelliNome" DataValueField="modelliID"
SelectedValue='<%# Bind("modelli.modelliID") %>'>
</aspropDownList>
</InsertItemTemplate>
<ItemTemplate>
<asp:Label ID="Label3" runat="server" Text='<%# Bind("[modelli.modelliID]") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="tipologie.tipologieID"
SortExpression="tipologie.tipologieID" ConvertEmptyStringToNull="true">
<EditItemTemplate>
<asp:TextBox ID="TextBox4" runat="server"
Text='<%# Bind("[tipologie.tipologieID]") %>'></asp:TextBox>
</EditItemTemplate>
<InsertItemTemplate>
<aspropDownList ID="DropDownList4" runat="server" DataSourceID="EDSTipologie"
DataTextField="tipologieNome" DataValueField="tipologieID"
SelectedValue='<%# Bind("tipologie.tipologieID") %>'>
</aspropDownList>
</InsertItemTemplate>
<ItemTemplate>
<asp:Label ID="Label4" runat="server"
Text='<%# Bind("[tipologie.tipologieID]") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:CommandField ButtonType="Button" ShowInsertButton="True" />
</Fields>
</aspetailsView>
<asp:EntityDataSource ID="EDSfornitori" runat="server"
ConnectionString="name=dbmagaEntities" DefaultContainerName="dbmagaEntities"
EntitySetName="fornitori" Select="it.[fornitoriID], it.[fornitoriNome]">
</asp:EntityDataSource>

<asp:EntityDataSource ID="EDSmarche" runat="server"
ConnectionString="name=dbmagaEntities" DefaultContainerName="dbmagaEntities"
EntitySetName="marche">
</asp:EntityDataSource>

<asp:EntityDataSource ID="EDSmodelli" runat="server"
ConnectionString="name=dbmagaEntities" DefaultContainerName="dbmagaEntities"
EntitySetName="modelli">
</asp:EntityDataSource>

<asp:EntityDataSource ID="EDSTipologie" runat="server"
ConnectionString="name=dbmagaEntities" DefaultContainerName="dbmagaEntities"
EntitySetName="tipologie">
</asp:EntityDataSource>




</asp:Content>

[djciko]

usa i tag [code]

[broggini.dav]

ecco il codice

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default2.aspx.cs" Inherits="Default2" %>
   <%@ Register assembly="System.Web.Entity, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" namespace="System.Web.UI.WebControls" tagprefix="asp" %>
  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">  <html xmlns="http://www.w3.org/1999/xhtml"> 

<head runat="server">     
<title></title> </head> 
<body>     
<form id="form1" runat="server">     
<div>          <asp:DetailsView ID="DetailsView1" runat="server" Height="50px" Width="125px"              AutoGenerateRows="False" DataKeyNames="articoliID" DataSourceID="EDSArticoli"              DefaultMode="Insert">
             <Fields>                 <asp:BoundField DataField="articoliID" HeaderText="articoliID" ReadOnly="True"                      SortExpression="articoliID" Visible="False" />
                 <asp:BoundField DataField="codice" HeaderText="codice"                      SortExpression="codice" />
                 <asp:BoundField DataField="articoliDescrizione"                      HeaderText="articoliDescrizione" SortExpression="articoliDescrizione" />
                 <asp:TemplateField HeaderText="fornitori.fornitoriID"                      SortExpression="fornitori.fornitoriID" ConvertEmptyStringToNull="true">
                     <EditItemTemplate>
                         <asp:TextBox ID="TextBox1" runat="server"                              Text='<%# Bind("[fornitori.fornitoriID]") %>'></asp:TextBox>
                     </EditItemTemplate>
                     <InsertItemTemplate>
                         <asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="EDSfornitori"                              DataTextField="fornitoriNome" DataValueField="fornitoriID"                              SelectedValue='<%# Bind("fornitori.fornitoriNome") %>'>
                         </asp:DropDownList>
                     </InsertItemTemplate>
                     <ItemTemplate>
                         <asp:Label ID="Label1" runat="server" Text='<%# Bind("[fornitori.fornitoriID]") %>'></asp:Label>
                     </ItemTemplate>
                 </asp:TemplateField>
                 <asp:TemplateField HeaderText="marche.marcheID"                      SortExpression="marche.marcheID" ConvertEmptyStringToNull="true">                     <EditItemTemplate>
                         <asp:TextBox ID="TextBox2" runat="server"                              Text='<%# Bind("[marche.marcheID]") %>'></asp:TextBox>
                     </EditItemTemplate>
                     <InsertItemTemplate>
                         <asp:DropDownList ID="DropDownList2" runat="server" DataSourceID="EDSmarche" DataTextField="marcheNome" DataValueField="marcheID"
                              SelectedValue='<%# Bind("marche.marcheID") %>'>
                         </asp:DropDownList>
                     </InsertItemTemplate>
                     <ItemTemplate>
                         <asp:Label ID="Label2" runat="server" Text='<%# Bind("[marche.marcheID]") %>'></asp:Label>
                     </ItemTemplate>
                 </asp:TemplateField>
                 <asp:TemplateField HeaderText="modelli.modelliID"                      SortExpression="modelli.modelliID" ConvertEmptyStringToNull="true">
                     <EditItemTemplate>
                         <asp:TextBox ID="TextBox3" runat="server"                              Text='<%# Bind("[modelli.modelliID]") %>'></asp:TextBox>
                     </EditItemTemplate>
                     <InsertItemTemplate>
                         <asp:DropDownList ID="DropDownList3" runat="server" DataSourceID="EDSmodelli" DataTextField="modelliNome" DataValueField="modelliID"       SelectedValue='<%# Bind("modelli.modelliID") %>'>
                         </asp:DropDownList>
                     </InsertItemTemplate>
                     <ItemTemplate>
                         <asp:Label ID="Label3" runat="server" Text='<%# Bind("[modelli.modelliID]") %>'></asp:Label>
                     </ItemTemplate>
                 </asp:TemplateField>
                 <asp:TemplateField HeaderText="tipologie.tipologieID"                      SortExpression="tipologie.tipologieID" ConvertEmptyStringToNull="true">                     <EditItemTemplate>
                         <asp:TextBox ID="TextBox4" runat="server"                              Text='<%# Bind("[tipologie.tipologieID]") %>'></asp:TextBox>                     </EditItemTemplate>
                     <InsertItemTemplate>
                         <asp:DropDownList ID="DropDownList4" runat="server" DataSourceID="EDSTipologie" DataTextField="tipologieNome" DataValueField="tipologieID"     SelectedValue='<%# Bind("tipologie.tipologieID") %>'>
                         </asp:DropDownList>
                     </InsertItemTemplate>
                     <ItemTemplate>
                         <asp:Label ID="Label4" runat="server" Text='<%# Bind("[tipologie.tipologieID]") %>'></asp:Label>
                     </ItemTemplate>
                 </asp:TemplateField>
                 <asp:CommandField ButtonType="Button" ShowInsertButton="True" />             </Fields>
         </asp:DetailsView>
                         <asp:EntityDataSource ID="EDSfornitori" runat="server" ConnectionString="name=dbmagaEntities" DefaultContainerName="dbmagaEntities" EntitySetName="fornitori" Select="it.[fornitoriID], it.[fornitoriNome]">
                         </asp:EntityDataSource>
                          <asp:EntityDataSource ID="EDSmarche" runat="server" ConnectionString="name=dbmagaEntities" DefaultContainerName="dbmagaEntities"                              EntitySetName="marche">
                         </asp:EntityDataSource>
                          <asp:EntityDataSource ID="EDSmodelli" runat="server"  ConnectionString="name=dbmagaEntities" DefaultContainerName="dbmagaEntities"                              EntitySetName="modelli">
                         </asp:EntityDataSource>
                          <asp:EntityDataSource ID="EDSTipologie" runat="server"  ConnectionString="name=dbmagaEntities" DefaultContainerName="dbmagaEntities"                              EntitySetName="tipologie">
                         </asp:EntityDataSource>
</div>
     <asp:EntityDataSource ID="EDSArticoli" runat="server"      ConnectionString="name=dbmagaEntities" DefaultContainerName="dbmagaEntities"      EnableDelete="True" EnableInsert="True" EnableUpdate="True"      EntitySetName="articoli" Include="fornitori, marche, modelli, tipologie"          AutoGenerateWhereClause="True">
 </asp:EntityDataSource>
     </form>
 </body>
 </html>