c# – 从供应商的Global.asax继承Global.asax时不会触发Application_Start

我正在尝试将代码添加到我没有源代码的第三方ASP.NET Web应用程序的application_start事件中.我是通过继承供应商的Global类来做到这一点的.这是代码(注意“new”关键字和对事件的基类版本的两次调用.这是因为基类方法不是抽象,虚拟或覆盖,我没有更改源代码) ：

public class CustomGlobal : vendorNamespace.Global
{
    new protected void Application_Start(object sender,EventArgs e)
    {
        var logName = "SPPCustom";
        if (!System.Diagnostics.EventLog.sourceExists(logName))
        System.Diagnostics.EventLog.CreateEventSource(logName,"Application");
        var text = "Hello from Application Start!";
        System.Diagnostics.EventLog.WriteEntry(logName,"Application started!");
        File.WriteallText(@"c:\ApplicationStart.txt",text);
        Debug.WriteLine(text);
        base.Application_Start(sender,e);
    }
    new protected void Session_Start(object sender,EventArgs e)
    {
        var logName = "SPPCustom";
        if (!System.Diagnostics.EventLog.sourceExists(logName))
            System.Diagnostics.EventLog.CreateEventSource(logName,"Application");
        System.Diagnostics.EventLog.WriteEntry(logName,"Session started!");
        base.Session_Start(sender,e);
    }
}

我在网站的global.asax文件中引用我的代码,如下所示：

<%@ Application Codebehind="Global.asax.cs" Inherits="MyNamespace.CustomGlobal" Language="C#" %>

Application_Start代码不会执行,但Session_Start代码会执行.我可以编写事件并从Session_Start写出文本文件但是Application_Start,nadda.

有谁知道这里发生了什么？

编辑：

这是执行Jan的建议后的代码：
公共类CustomGlobal：HttpApplication
    {
        private readonly Global _global;
        private readonly MethodInfo _appStartInfo;
        private readonly MethodInfo _sessionStartInfo;

public CustomGlobal()
    {
        _global = new Global();
        _appStartInfo = typeof(Global).getmethod("Application_Start",BindingFlags.Instance | BindingFlags.NonPublic);
        _sessionStartInfo = typeof(Global).getmethod("Session_Start",BindingFlags.Instance | BindingFlags.NonPublic);
    }

    protected void Application_Start(object sender,EventArgs e)
    {

        var logName = "SPPCustom";
        if (!System.Diagnostics.EventLog.sourceExists(logName))
            System.Diagnostics.EventLog.CreateEventSource(logName,"Application");
        var text = "Hello Patient Portal from Application Start!";
        System.Diagnostics.EventLog.WriteEntry(logName,"Application started!");
        File.WriteallText(@"c:\PatientPortalApplicationStart.txt",text);
        Debug.WriteLine(text);
        //_sxaGlobal.ApplicationStart(sender,e);
        _appStartInfo.Invoke(_global,new[] {sender,e});
    }
}

现在它抛出以下错误：

[NullReferenceException: Object reference not set to an instance of an object.]

Global.Application_Start(Object sender,EventArgs e)28

[TargetInvocationException：调用目标抛出了异常.]
   System.RuntimeMethodHandle._InvokeMethodFast(IRuntimeMethodInfo方法,Object target,Object []参数,SignatureStruct& sig,MethodAttributes methodAttributes,RuntimeType typeOwner)0
   System.RuntimeMethodHandle.InvokeMethodFast(IRuntimeMethodInfo方法,Signature sig,RuntimeType typeOwner)72
   System.Reflection.RuntimeMethodInfo.Invoke(Object obj,BindingFlags invokeAttr,Binder binder,Object [] parameters,CultureInfo culture,Boolean skipVisibilityChecks)251
   System.Reflection.RuntimeMethodInfo.Invoke(Object obj,CultureInfo文化)28
   System.Reflection.MethodBase.Invoke(Object obj,Object []参数)19
   CustomGlobal.Application_Start(Object sender,EventArgs e)231

[HttpException(0x80004005)：调用目标抛出了异常.]
   System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext context,HttpApplication app)9239341
   System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext,HttpContext context,MethodInfo [] handlers)131
   System.Web.HttpApplication.InitSpecial(HttpApplicationState状态,MethodInfo []处理程序,IntPtr appContext,HttpContext上下文)194
   System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext,HttpContext context)339
   System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext)253

[HttpException(0x80004005)：调用目标抛出了异常.]
   System.Web.HttpRuntime.FirstRequestinit(HttpContext context)9157968
   System.Web.HttpRuntime.EnsureFirstRequestinit(HttpContext context)97
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr,HttpContext context)256

解决方法

这是继承问题.当使用new关键字时,调用CustomGlobal.Application_Start()将执行您的代码,但调用((HttpApplication)CustomGlobal).Application_Start()将执行供应商的代码.

解决方案可能是私人成员的模式

public class CustomGlobal : HttpApplication
{
    private readonly vendorGlobal _global;
    private readonly MethodInfo _appStartInfo;

    public CustomGlobal()
    {
        _global = new vendorGlobal();
        _appStartInfo = typeof(vendorGlobal).getmethod("Application_Start",EventArgs e)
    {
        _appStartInfo.Invoke(_global,e});
        // your custom code
    }