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C# C# Objects Encapsulation with Properties Expression Bodied Members

Posted by Amy Kang
Amy Kang
17,188 Points

Unexpected symbol '=>' in class, struct, or interface member declaration

Getting this error when I compile my code with mono on my local machine (Ubuntu).

namespace TreehouseDefense
{
  class Invader
  {
    private readonly Path path;

    private int pathStep = 0;

    public MapLocation Location => this.path.GetLocationAt(this.pathStep);

    public Invader(Path path)
    {
      this.path = path;
    }

    public void Move() => this.pathStep += 1;
  }
}

2 Answers

Steven Parker
Steven Parker
241,434 Points
Steven Parker
Steven Parker
241,434 Points

:point_right: Expression Bodied Members are a recent language addition.

Check your mono/mcs version number. I believe this feature was first available in version 3.8.

The current version is 4.4 — perhaps it's time for an upgrade?

Amy Kang
Amy Kang
17,188 Points

Yep turns out it was my version of C#. I have version 4.0. Just wrote it long form instead.

Rikki MCguire
Rikki MCguire
2,232 Points
Rikki MCguire
Rikki MCguire
2,232 Points

you can also write it like this public void Move() { _pathStep += 1;}