The Expression is not valid in an include function

Question

Hi im trying to get some data from the foreign key column and when i use the then include operation i get the following error

System.InvalidOperationException: The expression 'p.BranchName' is invalid inside an 'Include' operation, since it does not represent a property access: 't => t.MyProperty'. To target navigations declared on derived types, use casting ('t => ((Derived)t).MyProperty') or the 'as' operator ('t => (t as Derived).MyProperty'). Collection navigation access can be filtered by composing Where, OrderBy(Descending), ThenBy(Descending), Skip or Take operations.

ill attach the repository code and the entities



and the post man error

Answer 1

Hi @Asjad Butt ,

System.InvalidOperationException: The expression 'p.BranchName' is invalid inside an 'Include' operation, since it does not represent a property access: 't => t.MyProperty'. To target navigations declared on derived types, use casting ('t => ((Derived)t).MyProperty') or the 'as' operator ('t => (t as Derived).MyProperty'). Collection navigation access can be filtered by composing Where, OrderBy(Descending), ThenBy(Descending), Skip or Take operations.

When using the Include or ThenInclude , we need to specify a navigation property, but in your query statement, the BranchName is just a string type, instead of the navigation property. So, it will show the above error.

To solve it, try to modify your code as below: I assume you want to load the BranchAdmin entity, change the BranchName to BranchAdmin:

        var students = await context.Students  
            .Include(p => p.Branch)  
            .ThenInclude(b => b.BranchAdmin)  
            .Include(p => p.Guardian)  
            .ToListAsync();  

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Best regards,
Dillion