Camera bug?

1

HI everyone, there’s my code for following the player by camera, but when i try to update the camera in game1.cs Update, it crashes with System.NullReferenceException: Object reference not set to an instance of an object. Here’s the code for my Camera.cs, hracX and hracY mean the player’s position.

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;


namespace TerraWorld
{
    class Camera
    {
        public Matrix transform;
        Viewport view;
        Vector2 centre;

        public Camera(Viewport newView)
        {
            view = newView;
        }

        public void Update(GameTime gameTime, int hracX, int hracY)
        {
            centre = new Vector2(hracX + (32 / 2) - 400, hracY + (32 / 2) - 400);
            transform = Matrix.CreateScale(new Vector3(1, 1, 0)) *
                Matrix.CreateTranslation(new Vector3(-centre.X, -centre.Y, 0));
        }
    }
}

and here’s how i update the camera kamera.Update(gameTime, hracX, hracY);,but for unkown reason it doesnt works, on XNA it worked.

Thanks for solution.