不斷移動pictureboxes的陣列C＃

Question

public int level = 1; 
    public PictureBox[] invaders; 

    public void spawn(int level) 
    { 
     int f = 0; 

     invaders = new PictureBox[100]; 
     PictureBox invader = new PictureBox(); 
     Bitmap img = (WindowsFormsApplication1.Properties.Resources.SpaceInvader); 
     for (int n = 32; n < (4 + level)*32; n=n+32) 
     { 
      for (int i = 90; i < 400; i = i + 37) 
      { 
       invaders[f] = new PictureBox(); 
       invaders[f].Location = new Point(i, n); 
       invaders[f].Size = new Size(20, 15); 
       invaders[f].Image = img; 
       invaders[f].SizeMode = PictureBoxSizeMode.StretchImage; 
       invaders[f].BackColor = Color.Transparent; 

       this.Controls.Add(invaders[f]); 

       f++; 
      } 
     } 
     timer2.Interval = 10; 
     timer2.Start(); 
    } 
    private void timer2_Tick(object sender, EventArgs e) 
    { 
     for (int i = 0; i < invaders.Length; i++) 
     { 
      invaders[i].Location = new Point(invaders[i].Location.X + 1, invaders[i].Location.Y); 
     } 
    } 

錯誤：

An unhandled exception of type 'System.NullReferenceException' occurred in SpaceInvaders.exe

所有圖像間移動一次，然後發生錯誤。任何解決方案

Answer 1

我建議使用GDI或DirectX在控件的表面上繪製圖像。 這將會非常快。我相信你之前沒有使用過directx，所以我建議你選擇一些簡單的例子來使用directx渲染圖像。它非常簡單。

爲GDI，你可以用這個簡單的例子 https://docs.microsoft.com/en-us/dotnet/framework/winforms/advanced/how-to-render-images-with-gdi