Compiler Error CS1945

  • Article

An expression tree may not contain an anonymous method expression.

Expression trees can only contain expressions. Anonymous methods can only represent statements.

To correct this error

  • Do not try to create an expression tree with a statement.

Example

The following code generates CS1945:

// cs1945.cs
using System;
using System.Linq.Expressions;

public delegate void D();
class Test
{
    static void Main()
    {
        Expression<Func<int, Func<int, bool>>> tree = (x => delegate(int i) { return true; }); // CS1945
    }
}

See Also

Concepts

Expression Trees

Reference

Statements, Expressions, and Operators (C# Programming Guide)