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c#.netentity-frameworklinq-to-entitiesentity-framework-core

LINQ to Entities Where clause with custom method

I'm using Entity Framework Core (2.0) and I have the following doubt.

I'm not sure about what happens when I do this:

context.Customers.Where(c => MyCustomMethod(c));

bool MyCustomMethod(Customer c) 
{
    return c.Name.StartsWith("Something");
}

Does it translate to SQL without problems?

Is it different than writing:

context.Customers.Where(c => c.StartsWith("Something"));

In short, will I be able to wrap my validations for the Where clase inside a method? Does it break the translation to SQL?

Solution

  • No, you cannot call your custom method in EF LINQ query because EF will not be able to generate expression tree of the method and so it cannot translate it to SQL.

    For more info about expression trees, refer to the link.