Passing func as parameter in Linq to Entities and 'Internal .NET Framework Data Provider error 1025' error
entity-framework, lambda, linq-to-entities
Solution
Well the EF can only translate Expressions, not functions.
i.e. it can translate this:
Expression<Func<TaskUser,bool>>
but not this:
Func<TaskUser,bool>
As for how to merge expressions (in pseudo code):
Expression<Func<TaskUser, bool>> expression = a => a.User.ID == 1;
return tasks.Where(t => t.TaskUsers.Any(expression));
There are probably some Expression guru's who can help with that.
I suggest a followup question focused on that particular problem
Alex
Problem
We have a class called Task: ``` public partial class Task : EntityObject { public EntityCollection<TaskUser> TaskUsers { get {...} set{...} } } ``` It has navigation property called TaskUsers, which contains users attached to this taks: ``` public partial class TaskUser : EntityObject { public User User { get {...} set { } } } ``` Every TaskUser object has User object. We are given `IQueryable<Task> tasks`. We want to find tasks assigned to user with ID = 1. When we use ``` tasks.Where(t => t.TaskUsers.Any(a => a.User.ID == 1)) ``` everything works fine. When we use ``` Func<TaskUser, bool> function = a => a.User.ID == 1; return tasks.Where(t => t.TaskUsers.Any(function)); ``` we get nice `'Internal .NET Framework Data Provider error 1025'` error. Why? I want to build much more complicated filters using `Expression` class, but if I can't pass simple `Func`, this can't be done. What should I do? EDIT Maybe ``` Func<TaskUser, bool> function = a => a.User.ID == 1; return tasks.Where(t => t.TaskUsers.Any(function)); ``` doesn't work, but ``` Expression<Func<TaskUser, bool>> expression = a => a.User.ID == 1; return tasks.Where(t => t.TaskUsers.AsQueryable().Any(expression)); ``` works! That is all I needed.