流氓異常，System.InvalidOperationException，XNA

Question

我的xna游戲具有此“流氓” System.InvalidOperationException，該異常僅偶爾發生，並且似乎是隨機觸發的，或者至少是出於我的控制輸入明智的觸發。 在按開始並加載第一個菜單屏幕后，（ 有時我會使用GameStateManagement示例作為我的游戲的基礎，如果有幫助的話）游戲有時但並非總是在“ foreach（GameScreen屏幕）的“ in”部分拋出System.InvalidOperationException在屏幕上）“該方法的完整代碼：

            /// <summary>
    /// Tells each screen to draw itself.
    /// </summary>
    public override void Draw(GameTime gameTime)
    {

        foreach (GameScreen screen in screens) //exception thrown at the "in" part
        {
            if (screen.ScreenState == ScreenState.Hidden)
                continue;

            screen.Draw(gameTime);
        }
    }

老實說，對於觸發該異常的原因一無所知，因為我沒有做任何與何時引發異常以及何時沒有引發異常的事情。 我不確定是否能幫到您，但這是例外情況詳細信息

   at System.Collections.Generic.List`1.Enumerator.MoveNext()
   at GameStateManagement.ScreenManager.Draw(GameTime gameTime)
   at Microsoft.Xna.Framework.Game.Draw(GameTime gameTime)
   at GameStateManagement.GameStateManagementGame.Draw(GameTime gameTime)
   at Microsoft.Xna.Framework.Game.DrawFrame()
   at Microsoft.Xna.Framework.Game.Tick()
   at Microsoft.Xna.Framework.Game.HostIdle(Object sender, EventArgs e)
   at Microsoft.Xna.Framework.GameHost.OnIdle()
   at Microsoft.Xna.Framework.XboxGameHost.RunOneFrame()
   at Microsoft.Xna.Framework.XboxGameHost.Run()
   at Microsoft.Xna.Framework.Game.RunGame(Boolean useBlockingRun)
   at Microsoft.Xna.Framework.Game.Run()
   at GameStateManagement.Program.Main()
}   System.Exception {System.InvalidOperationException}

這是調用堆棧：

>   GameStateManagementSample.exe!GameStateManagement.ScreenManager.Draw(Microsoft.Xna.Framework.GameTime gameTime) Line 338 + 0x33 bytes   C#
Microsoft.Xna.Framework.Game.dll!Microsoft.Xna.Framework.Game.Draw(Microsoft.Xna.Framework.GameTime gameTime) + 0x4d bytes  
GameStateManagementSample.exe!GameStateManagement.GameStateManagementGame.Draw(Microsoft.Xna.Framework.GameTime gameTime) Line 89 + 0x7 bytes   C#
Microsoft.Xna.Framework.Game.dll!Microsoft.Xna.Framework.Game.DrawFrame() + 0x6a bytes  
Microsoft.Xna.Framework.Game.dll!Microsoft.Xna.Framework.Game.Tick() + 0x2a9 bytes  
Microsoft.Xna.Framework.Game.dll!Microsoft.Xna.Framework.Game.HostIdle(object sender, System.EventArgs e) + 0x6 bytes   
Microsoft.Xna.Framework.Game.dll!Microsoft.Xna.Framework.GameHost.OnIdle() + 0x19 bytes 
Microsoft.Xna.Framework.Game.dll!Microsoft.Xna.Framework.XboxGameHost.RunOneFrame() + 0xc bytes 
Microsoft.Xna.Framework.Game.dll!Microsoft.Xna.Framework.XboxGameHost.Run() + 0x1b bytes    
Microsoft.Xna.Framework.Game.dll!Microsoft.Xna.Framework.Game.RunGame(bool useBlockingRun) + 0x9c bytes 
Microsoft.Xna.Framework.Game.dll!Microsoft.Xna.Framework.Game.Run() + 0x7 bytes 
GameStateManagementSample.exe!GameStateManagement.Program.Main() Line 108 + 0x6 bytes   C#

謝謝！ Ivatrix。

Answer 1

您的游戲代碼似乎正在修改您未考慮的某些代碼路徑上的screens 。 看看IEnumerator.MoveNext上的文檔。

創建枚舉器后，對集合進行了修改。