Compiler Error CS1946

An anonymous method expression cannot be converted to an expression tree.

An anonymous method represents a set of statements but an expression tree must not contain a statement. Therefore an anonymous method cannot be represented by an expression tree.

To correct this error

  • Change the anonymous method to a lambda expression.

The following example generates CS1946:

// cs1946.cs
using System;
    using System.Linq.Expressions;

    public delegate void D();

    class Test
        static void Main()
            Expression<D> tree = delegate() { }; //CS1946
            // Try using a lambda expression instead.
            // Expression<D> tree = (x) => x + 1;