Error: EntitySet 'Building' that was specified in page markup does not exist on the Container

I've setup an ItemTeplate like so in a GridView:

<asp:TemplateField HeaderText="Building">
    <ItemTemplate>
        <asp:Label 
            ID="lblBuilding" 
            Text='<%# Bind("Building1.building_name") %>' 
            runat="server" />
    </ItemTemplate>开发者_高级运维;
    <EditItemTemplate>
        <asp:EntityDataSource 
            ID="EditHousingDataSource" 
            runat="server" 
            EnableDelete="true" 
            ConnectionString="name=pbu_housingEntities"
            DefaultContainerName="pbu_housingEntities" 
            EnableFlattening="false" 
            EntitySetName="Building" 
            EntityTypeFilter="Building" />
        <asp:DropDownList 
            ID="ddlBuilding" 
            runat="server" 
            DataSourceID="EditHousingDataSource"
            DataTextField="building_name" 
            DataValueField="ID" />
    </EditItemTemplate>
</asp:TemplateField>

I'm receiving the error:

EntitySet 'Building' that was specified in page markup does not exist on the Container.

Any ideas on why? There is definitely a Building entity in the pbu_housingEntities?

Here ...

EntitySetName="Building"

... you don't have to specify the class name of your entity but the name of the ObjectSet<Building> property of your derived ObjectContext.

This might be called Buildings. You can check this in your edmx model configuration or in the generated file for your derived ObjectContext.