2

我得到这个例外：

NullReferenceException
Object reference not set to an instance of an object
   at Namespace.TheClass.TheMethod()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.runTryCode(Object userData)
   at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()

在这段代码中：

public class TheClass : TheBaseClass
{
    protected IList1 List;
    public object Object1;
    public ManualResetEvent MrEvent = new ManualResetEvent(false);
    readonly Attr1 Attr1;
    readonly Attr2 Attr2;
    readonly EventHandler<Class1> BeginHandler, EndHandler;
    readonly EventHandler<Class2> Handler2;
    readonly EventHandler<Class3> Handler3;

    public TheClass(Attr1 attr1, Attr2 attr2, EventHandler<Class1> beginHandler, EventHandler<Class1> endHandler, EventHandler<Class2> handler2, EventHandler<Class3> handler3)
    {
        this.Attr1 = attr1;
        this.Attr2 = attr2;
        this.BeginHandler = beginHandler;
        this.EndHandler = endHandler;
        this.Handler2 = handler2;
        this.Handler3 = handler3;
        Thread t = new Thread(Run);
        t.IsBackground = true;
        t.Start();
    }

    void TheMethod()
    {
        Args1 args1 = new Args1();
        if (BeginHandler != null)
        {
            try
            {
                BeginHandler(this, args1);
            }
            catch { }
        }

        try
        {
            List = GetList(args1);
        }
        catch { }

        if (List != null)
        {
            List.Event1 += new EventHandler<Args2>(List_Event1);
        }

        if (Handler3 != null)
        {
            try
            {
                Args3 args3 = new Args3(args1.Attr1, args1.Attr2);
                Handler3(this, args3);
                this.Object1 = args3.Object1;
            }
            catch { }
        }

        if (this.Object1 == null)
        {
            if (args1.Attr1 != null)
                try
                {
                    this.Object1 = Class4.GetObject(args1.Attr1);
                }
                catch { }
        }

        MrEvent.Set();
        Method1();
        Method2();

        if (List != null)
        {
            List.Event1 -= new EventHandler<Args2>(List_Event1);
        }

        if (EndHandler != null)
        {
            try
            {
                EndHandler(this, args1);
            }
            catch { }
        }
    }
}

我看不到任何地方可以引发提到的句柄空异常。你看到有人吗？

对 Veer：你怎么能如此改变我的问题的意思？
对那些批准它的人：你怎么能同意它？

4

2 回答 2

1

在这段代码中，在 try catch 块内你不会得到 null 异常，因为 catch 块是空的，所以异常不会抛出一边，检查其他对象。

于 2013-06-04T10:08:30.417 回答
1

NullReferenceException 可以从内联方法中抛出。查看方法 1 和方法 2。

于 2013-06-10T08:51:13.290 回答