Thursday, December 10, 2009

FieldValue in DynamicData ForeignKeyField is null, but it should not be

I am using ADO.NET Entity Framework and Dynamic Data in a ASP.NET Formview. It works great! Let’s pretend I am working with a Person entity. Then I added a Foreign key to my table (and EF Model) to another table called it Gender. I add the DynamicControl to my formview for the foreign key by setting the DataField to the name of the relationship from Person to Gener, in this case it is called Gender.

I added this to EditItemTemplate

<asp:DynamicControl ID="GenderDynamicControl" runat="server" DataField="Gender" Mode="Edit" ValidationGroup="Edit"  />

The two-way binding works great.

Then I go to the ItemTemplate and add

<asp:DynamicControl ID="GenderDynamicControl" runat="server" DataField="Gender" Mode="ReadOnly" ValidationGroup="ReadOnly"  />

I then test, and see that the ItemTemplate / Read only version of this doesn’t show any value. After debugging and looking at the FieldValue property in ForeignKey.ascx.cs I see that it is null when it should not be since the row I was looking at had a GenderID specified in the Person table.

Then I looked at the CRUD interface that you get for free when you create a Dynamic Data Web Site. It works great! That made no sense to me, but then I realized that the EntityDataSource I was using did NOT include the Gender entity, so this entity was not loaded. This is VERY characteristic of ADO.NET Entity Framework since it does lazy loading and requires that you specify what you want loaded. If you don’t, you don’t get the data.

So, the real solution was to just modify my EntityDataSource so that I include the Gender table as shown below. Some of the properties have been removed for simplicity in the code.

<asp:EntityDataSource ID="dsPerson" runat="server" 

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