How to Change Navigation Property Name with t4 Template

Question

    Generally, we desgine database tables and then generate edmx. But when the tables is designed like this:

    Product:

• ProductID
• CategoryEnumID
• QuelityEnumID
• CompanyEnumID

    Enum:

• EnumID
• Display
• Value

    In the Product table, there exists 3 foreign keys related with Enum table. So in the edmx file, Product Entity Object has 3 Navigation Property, Enum1, Enum2, Enum3. Enum1, Enum2, Enum3 is not convenient whe we program and I want to change the navigation property names to CategoryEnum, QuelityEnum, CompanyEnum.

    Now, I want to change the Navigation Property Name with t4 file. (How to do this, please reference this paper .)

    I do this successfully, but when I run my code, a exception show like this:

System.Data.MappingException was unhandled by user code

 Message=CLR. "Eps.Dao.BusinessPolicy" 's member "ServiceFeeTypeEnumDictionary" doesn't exist in Conceptual Model Type "Eps.Dao.BusinessPolicy"。

    I think whether that means the navigation property's name must match with the type name in conceptual model. If it's true, we should modify the conceptual model? That is horrible.

    How to solve the problem or Is there another way to solve the problem? Thanks.

Answer 1

If you are using POCO, then the conceptual model names and the class/proeprty names must match. If you update your EDMX file to have the correct/desired navigation proeprty names, the navigation properties will have correct names when they are code generated. Is there a reason you don't want to update the edmx file?

Jeff

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Answer 2

Thank you for your reply. I'm not using POCO, just generel edm. What I'm doing is that, after code generated, I want to modify the navingation property name with code generation item. For example, change Product's navigation property names "Enum1, Enum2, Enum3" to "CategoryEnum, QuelityEnum, CompanyEnum".

Answer 3

Hello Johnny,

 

Thanks for your post.

As I know, you could use the self-tracking entities.  Starting with the Entity Framework version 4, self-tracking entities can help you track changes in any tier. A self-tracking entity is an entity built from a Text Template Transformation Toolkit (T4) template that generates entity types that have the ability to record changes to scalar, complex, and navigation properties.

The ADO.NET Self-Tracking Entity Generator Template is available in Visual Studio 2010. For more information, see Walkthrough: Serialize Self-Tracking Entities.

I hope this can help you.

 

Have a nice day, 

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Jackie Sun [MSFT]
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Answer 4

Hello

I have this problem too, do you find any way?