Entity Framework: Assign entity to property of another entity
Question
I have these entities (this is just an abstraction I created for this post):
- Language
- District
- Description
These are the references between them:
- District * - 1 Language
- Description * - 1 Language
- District 1 - 1 Description
If I fetch like this:
var myFetch = from c in context.Districts
where c.Id = 10
select new { DistrictId = c.Id, Lang = c.Language };
and after that, I try to assign it to Description like this:
Description desc = Description.CreateDescription(0, "My description");
desc.DistrictReference.EntityKey = new EntityKey("MyEntities.Descriptions", "DistrictId", myFetch.DistrictId);
desc.Language = myFetch.Lang; //throws error
The error thrown is:
System.InvalidOperationException: The relationship cannot be defined because the EntitySet name 'MyEntities.Descriptions' is not valid for the role 'District' in association set name 'MyEntities.District_Description'.
What am I doing wrong?
Solution
if myFetch
were to be an instance of the class District
you could do it programmatically:
desc.DistrictReference.EntityKey = new EntityKey(
String.Format(
"{0}.{1}",
myFetch.EntityKey.EntityContainerName,
myFetch.EntityKey.EntitySetName),
"DistrictId",
myFetch.DistrictId);
OTHER TIPS
Just what the message says: You specified the wrong entity set name.
- Open your EDMX.
- Open the Model Browser window.
- Find the District entity in the Model Browser
- Right click it, choose "Properties"
- Note the correct Entity Set name
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