问题:

Pass by Value strikes again!!

player.Vector.X += player.Speed * (float)gameTime.ElapsedGameTime.TotalSeconds;

does not work.

Vector2 v = player.Vector;
v.X -= player.Speed * (float)gameTime.ElapsedGameTime.TotalSeconds;
player.Vector = v;

fixes this problem.

This is explained here: Can't modify XNA Vector components

The answer was very well explained and works just fine, but it has been 4 years since it was posted. My question is, since its been 4 years, is there a better way to fix this problem now?

I have about 100 lines of this I need to fix, and was hoping there was some sort of shortcut by now.

回答1:

There is probably never going to be a "shortcut" for this since it's a feature of the fundamental difference between value types and reference types.

回答2:

You can't directly modify a Vector's X, Y, Z, etc properties in XNA. What you can try is creating a new Vector2 based off the player's like this. This would reduce your 3 lines of code to 1 (if that's what your going for):

player.Vector = New Vector2(player.Vector.X - player.Speed * 
    (float)gameTime.ElapsedGameTime.TotalSeconds, player.Vector.Y);

This should do exactly what the "fix" did, except in one line. The same idea would apply to Vector3 or Vector4, and if you wanted to modify more than one property of the vector.