Question

从字面上看，无论功能/方法是什么，它都会让游戏崩溃。我有两个项目，一个用于UI，一个用于Engine。 UI包含Forms应用程序。 Engine包含一个World.cs静态类。如果我尝试从World引用函数/方法（但不是变量），它将抛出异常。我甚至做了一个功能：

public static void Potato()
{
    int pot;
    pot = 0;
}

在World.cs中，在CoreUI.cs（表单应用程序）中引用它：

World.Potato();

它引发了一个例外。它只会引发World类的异常。我有两个其他公共静态类，我可以引用，没有异常抛出。任何人都可以解释发生了什么？如果我需要提供更多代码，我会。谢谢！

World.cs：

using System;
using System.Collections.Generic;
using System.Text;

namespace Engine
{
    public static class World
    {
    public static readonly int[] world;
    public const int worldSize = 20;

    private static Random rand = new Random();

    //Constructor
    static World()
    {
        GenerateWorld();
    }
    private static void GenerateWorld()
    {
        for (int i = 1; i < worldSize-2; i += 1)
        {
            world[i] = ChooseLandType(rand.NextDouble());
        }
        world[0] = 0;
        world[19] = 4;
    }
    private static int ChooseLandType(double a)
    {
        if (a <= 0.5d) return 0;
        else if (a > 0.5d && a <= 0.55d) return 1;
        else if (a > 0.55d && a <= 0.8d) return 2;
        else if (a > 0.8d && a <= 0.9d) return 3;
        else if (a > 0.9d) return 4;
        else return 0;
    }
    public static int GetLocationType(int a)
    {
        if (a < worldSize) return world[a];
        else return 0;
    }
}
}

CoreUI.cs中的相关代码：

private void btnForward_Click(object sender, EventArgs e)
    {
        _player.MoveTo(_player.Y + 1);
        float a = (100f * (_player.Y / 20f));
        a = Clampf(a,0,100);
        pbPos.Value = (int)a;
        //The next line is the Thrown Exception
        pBoxIMG.Image = GetImage(World.GetLocationType(_player.Y));
    }

复制到剪贴板的异常详细信息：

System.TypeInitializationException was unhandled
  HResult=-2146233036
  Message=The type initializer for 'Engine.World' threw an exception.
  Source=Engine
  TypeName=Engine.World
  StackTrace:
       at Engine.World.GetLocationType(Int32 a)
       at SomeProgram.CoreUI.btnForward_Click(Object sender, EventArgs e) in C:\Users\user\Documents\Visual Studio 2010\Projects\SomeProgram\SomeProgram\CoreUI.cs:line 43
       at System.Windows.Forms.Control.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
       at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ButtonBase.WndProc(Message& m)
       at System.Windows.Forms.Button.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(Form mainForm)
       at SomeProgram.Program.Main() in C:\Users\user\Documents\Visual Studio 2010\Projects\SomeProgram\SomeProgram\Program.cs:line 18
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.NullReferenceException
       HResult=-2147467261
       Message=Object reference not set to an instance of an object.
       Source=Engine
       StackTrace:
            at Engine.World.GenerateWorld() in C:\Users\user\Documents\Visual Studio 2010\Projects\SomeProgram\Engine\World.cs:line 23
            at Engine.World..cctor() in C:\Users\user\Documents\Visual Studio 2010\Projects\SomeProgram\Engine\World.cs:line 17
       InnerException:

简化为：

'Engine.World'的类型初始化程序引发了异常。

Answer 1

您没有初始化world

所以你需要添加

static World()
{
    world = new int[worldSize];
    GenerateWorld();
}

Answer 2

您所显示的初始方法没有任何问题，因此问题出在代码的另一部分。

在您已经展示的课程中，有一个静态构造函数：

class World
{
    // ...

    static World()
    {
        GenerateWorld();
    }

    // ...
}

静态构造函数（和静态初始化程序）可能会被懒惰地执行 - 也就是说，无论何时第一次使用该特定类。如果它们运行正常，那么没有问题，你甚至都不会注意到它们。

但是如果它们因任何原因碰巧抛出异常，它会出现（在调试期间），好像你的方法抛出它一样。但实际上你的初始方法是无辜的 - 它只是导致CLR在加载特定类时运行实际的罪魁祸首方法。

换句话说，异常是从GenerateWorld()方法抛出的。正如其他人所说，这是因为你正在索引一个数组：

world[i] = // ...

但是你还没有首先初始化数组：

world = new int[worldSize];

C＃ALL函数和方法抛出异常

2 个答案: