Error CS1612 The return value of "Figur.Standort" is not a variable and therefore cannot be changed

Question

Hello this is my first question on this page because neither my teacher nor ChatGPT could help me, both said that they dont find an mistake.

I want to make an program that tests if the knight can run over every square on the chessboard without using a sinle square twice.

Now i have the Problem that my IDE (Visual Code Community) gives me the (NET7.0)

Error: "CS1612"

which says: "The return value of "Figur.Standort" is not a variable and therefore cannot be changed."

(The Error is in the Method "Bewegen")

class program
{
    static void Main()
    {
        //Playfield chessboard
        bool[,] Spielfeld = new bool[8, 8]; ;

        //Mögliche Spielzüge des Springers
        Pos[] Spielzüge = new Pos[8];
        Spielzüge[0] = new Pos(1, 2);
        Spielzüge[1] = new Pos(1, -2);
        Spielzüge[2] = new Pos(2, 1);
        Spielzüge[3] = new Pos(2, -1);
        Spielzüge[4] = new Pos(-1, 2);
        Spielzüge[5] = new Pos(-1, -2);
        Spielzüge[6] = new Pos(-2, 1);
        Spielzüge[7] = new Pos(-2, -1);

        //Startposition of the knight on the playfield
        Pos Position = new Pos(1, 0);

        //Knight
        Figur Springer = new Figur(Spielzüge, Position);

        //Mainloop
        while (true)
        {


        }
    }
}
class Figur
{
    public Pos[] Möglichkeiten { get; set; }
    public Pos Standort { get; set; }

    public Figur(Pos[] möglichkeiten, Pos standort)
    {
        Möglichkeiten = möglichkeiten;
        Standort = standort;
    }
    public void Bewegen(int zugIndex)
    {
        Standort.X += Möglichkeiten[zugIndex].X;
        Standort.Y += Möglichkeiten[zugIndex].Y;
    }
}
struct Pos
{
    public int X { get; set; }
    public int Y { get; set; }
    public Pos(int x, int y)
    {
        X = x;
        Y = y;
    }
}

i Expectet that the Method "Bewegen" uses the in Möglichkeiten[Index] saved Pos to calculate the new "Standort"

Answer 1

Pos is a value type (struct), therefore whenever you access the property Standort, you will get a copy and thus are not able to modify the X/Y properties of the original.

Option 1: change to a reference type by replacing struct Pos by class Pos.

Option 2: assign a new Pos to Standort:

Standort = new Pos(Standort.X + Möglichkeiten[zugIndex].X, Standort.Y + Möglichkeiten[zugIndex].Y);