Convert Expression<Func<IBar, T>> to Expression<Func<Bar, T>>
c#, lambda, linq
Solution
Since this case is simple and related to "casting" issues only, there is a shortcut:
public void SomeMethodExpression(Expression<Func<IBar, bool>> expression)
{
Expression<Func<Bar, bool>> lambda = Expression.Lambda<Func<Bar, bool>>(expression.Body, expression.Parameters);
var found = _foobar.AnyExpression(lambda);
}
Problem
How do you convert from `Expression<Func<IBar, T>>` to `Expression<Func<Bar, T>>` when Bar implements IBar? There is the answer to this more generic question: Convert Expression<Func<T1,bool>> to Expression<Func<T2,bool> dynamically Is that the best method in this case? Is there not an easier way given that Bar implements IBar? So, given this contrived example code: ``` public class Foo<T> { private readonly List<T> _list = new List<T>(); public void Add(T item) { _list.Add(item); } public bool AnyFunc(Func<T, bool> predicate) { return _list.Any(predicate); } public bool AnyExpression(Expression<Func<T, bool>> expression) { return _list.AsQueryable().Any(expression); } } public interface IBar { string Name { get; } } public class Bar : IBar { public string Name { get; set; } } ``` This demonstrates the problem: ``` public class Test() { private Foo<Bar> _foobar = new Foo<Bar>(); public void SomeMethodFunc(Func<IBar, bool> predicate) { // WILL COMPILE AND WORKS, casts from Func<IBar, bool> to Func<Bar, bool> var found = _foobar.AnyFunc(predicate); } public void SomeMethodExpression(Expression<Func<IBar, bool>> expression) { // WON'T COMPILE - Can't cast from Expression<Func<IBar, bool>> to Expression<Func<Bar, bool>> var found = _foobar.AnyExpression(expression); } } ``` Any ideas how I can accomplish something similar to SomeMethodExpression?