asp:EntityDataSource failing to update or delete gridview - asp.net

Question

I have a gridview of vendor bids that have foreign keys to a vendors table and a product table.
Here is my gridview and my datasource.
<table>
<asp:GridView ID="GridViewVendorBids" runat="server" AutoGenerateColumns="False"
DataSourceID="VendorBidsDS" DataKeyNames="autRecNum" ForeColor="#333333" CellPadding="4"
GridLines="None" AllowPaging="True" AllowSorting="True">
<AlternatingRowStyle BackColor="White" ForeColor="#284775" />
<Columns>
<asp:CommandField ShowEditButton="true" />
<asp:BoundField DataField="dtmBidDate" HeaderText="Bid Date" SortExpression="dtmBidDate"
DataFormatString="{0:MM/dd/yyyy}" ApplyFormatInEditMode="true" />
<asp:TemplateField HeaderText="Vendor Name" SortExpression="it.tblVendors.strVendorName">
<ItemTemplate>
<asp:Label ID="lblVendorName" runat="server" Text='<%# Eval("tblVendors.strVendorName") %>' />
</ItemTemplate>
<EditItemTemplate>
<asp:DropDownList ID="ddlVendorList" runat="server" DataTextField="strVendorName"
DataSource='<%# getVendorList() %>' DataValueField="strVendorCode" AutoPostBack="false"
SelectedValue='<%# Bind("strVendorCode") %>' DropDownStyle="DropDownList" AutoCompleteMode="SuggestAppend"
CssClass="comboBoxInsideModalPopup" Width="250px" MaxLength="0" Style="display: inline;
top: 0px; left: 0px;" ItemInsertLocation="Append" RenderMode="Inline" Height="16px" />
</EditItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Product Name" SortExpression="it.tblProducts.strProductName">
<ItemTemplate>
<asp:Label ID="lblProductName" runat="server" Text='<%# Eval("tblProducts.strProductName") %>' />
</ItemTemplate>
<EditItemTemplate>
<asp:DropDownList ID="ddlProductList" runat="server" DataTextField="strProductName"
DataSource='<%# getProductList() %>' DataValueField="strProductCode" AutoPostBack="false"
SelectedValue='<%# Bind("strProductCode") %>' DropDownStyle="DropDownList" AutoCompleteMode="SuggestAppend"
CssClass="comboBoxInsideModalPopup" Width="300px" MaxLength="0" Style="display: inline;
top: 0px; left: 0px;" ItemInsertLocation="Append" RenderMode="Inline" Height="16px" />
</EditItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Unit" SortExpression="it.tblProducts.strUnitDesc">
<ItemTemplate>
<asp:Label ID="lblUnitDesc" runat="server" Text='<%# Eval("tblProducts.strUnitDesc") %>' />
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="sngBid" HeaderText="Bid" SortExpression="sngBid" ItemStyle-HorizontalAlign="Right"
DataFormatString="{0:0.00}" />
<asp:BoundField DataField="strBidType" HeaderText="Bid Type" SortExpression="strBidType"
ReadOnly="true" />
<asp:CommandField ShowDeleteButton="true" />
</Columns>
</asp:GridView>
</table>
<asp:EntityDataSource ID="VendorBidsDS" runat="server" ConnectionString="name=IMSEntities"
DefaultContainerName="IMSEntities" EntitySetName="tblVendorBid" Include="tblVendors,tblProducts"
EnableFlattening="False" OrderBy="it.dtmBidDate DESC" EnableDelete="true" EnableUpdate="true">
</asp:EntityDataSource>
When I press the update or delete key I get the following error:
No key property values were found during an update or delete operation. Check to ensure that key properties specified as binding expressions are available to the data source.
I found this post which is very similar to my problem but when I tried the answer I still get the same error.
Any help is appreciated. Thanks.

Answer 1

For the entity datasource you will need a primary key for the table.it allows you to change the records...After adding the primary key right click on entity datasource & select update database

Answer 2

Is "autRecNum" the only primary key of your VendorBidsDS Table?
You may check your Data Source Configuration whether primary key and foreign key are set properly. Also you may check if the Delete/Update Rule for FKey is set to Cascade if the other table is not updated.
And in " SelectedValue='<%# Bind("strProductCode") %>' ", "strProductCode" should be entity property instead of database column.
That's the few points I can remember from my previous project long long time ago.
Hope it can help you.

Answer 3

I got the "No key property values were found..." error because I was trying to save twice back to an EntityDataSource without a valid primary key. The StoreGeneratedPattern setting is correctly set to Identity and the first Insert ran correctly however the subsequent update fails - presumably because the primary key hasn't yet be set.
Basically I had manually inserted a row (using DbContext) and ran context.SaveChanges() but then my Telerik Grid translated the "Update" CommandName of the button to run another update command after the insert, causing this error. The error doesn't occur when updating existing rows, so it's very likely related to the primary key of a newly inserted row.
To solve the issue I simply set the CommandName of the button to "Cancel". My manual insert/update still runs, but then the Grid doesn't attempt another update operation and correctly closes the row I'm editing.