Application_Start赢得'；从供应商处继承Global.asax时不要激发'；s Global

本文关键字：Global asax Start 赢得 Application 供应商 继承 | 更新日期: 2023-09-27 18:22:00

我正在尝试将代码添加到第三方ASP.NET web应用程序的application_start事件中，但我没有该应用程序的源代码。我是通过继承供应商的Global类来实现这一点的。以下是代码（注意"new"关键字和对事件基类版本的两个调用。这是因为基类方法不是抽象的、虚拟的或重写的，我没有更改这一点的源代码）：

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文件中引用了我的代码，如下所示：

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

Application_Start代码不执行，但Session_Start代码执行。我可以从Session_Start，但Application_Start，nadda编写事件和文本文件。

有人知道这里发生了什么吗？

编辑：

以下是在执行Jan的建议后的代码：公共类CustomGlobal:HttpApplication{private只读全局（_Global）；私有只读方法信息_appStartInfo；private只读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（对象发送器，EventArgs e）+28

[TargetInvocationException:调用的目标引发了异常。]System.RuntimeMethodHandle.InvokeMethodFast（IRuntimeMethodInfo方法，Object目标，Object[]参数，SignatureStruct&sig，MethodAttributes方法属性，RuntimeType typeOwner）+0System.RuntimeMethodHandle.IInvokeMethodFast（IRuntimeMethodInfo方法，Object目标，Object[]参数，Signature sig，MethodAttributes方法属性，RuntimeType typeOwner）+72System.Reflection.RuntimeMethodInfo.Invoke（Object obj，BindingFlags invokeAttr，Binder Binder，Object[]参数，CultureInfo区域性，布尔skipVisibilityChecks）+251System.Reflection.RuntimeMethodInfo.Invoke（Object obj，BindingFlags invokeAttr，Binder Binder，Object[]参数，CultureInfo区域性）+28System.Reflection.MethodBase.Invoke（Object obj，Object[]parameters）+19CustomGlobal.Application_Start（对象发送器，EventArgs e）+231

[HttpException（0x80004005）：调用的目标引发了异常。]System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode（HttpContext上下文，HttpApplication应用程序）+923941System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS（IntPtr appContext、HttpContext上下文、MethodInfo[]处理程序）+131System.Web.HttpApplication.InitSpecial（HttpApplicationState状态，MethodInfo[]处理程序，IntPtr appContext，HttpContext上下文）+194System.Web.HttpApplicationFactory.GetSpecialApplicationInstance（IntPtr appContext，HttpContext context）+339System.Web.Hosting.PipelineRuntime.InitializeApplication（IntPtr appContext）+253

[HttpException（0x80004005）：调用的目标引发了异常。]System.Web.HttpRuntime.FirstRequestInit（HttpContext上下文）+9157968System.Web.HttpRuntime.EnsureFirstRequestInit（HttpContext上下文）+97System.Web.HttpRuntime.ProcessRequestNotificationPrivate（IIS7WorkerRequest wr，HttpContext上下文）+256

Application_Start赢得'；从供应商处继承Global.asax时不要激发'；s Global

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。

解决方案可以是具有私人成员的模式

public class CustomGlobal : HttpApplication
{
    private readonly VendorGlobal _global;
    private readonly MethodInfo _appStartInfo;
    public CustomGlobal()
    {
        _global = new VendorGlobal();
        _appStartInfo = typeof(VendorGlobal).GetMethod("Application_Start", BindingFlags.Instance | BindingFlags.NonPublic);
    }
    protected void Application_Start(object sender, EventArgs e)
    {
        _appStartInfo.Invoke(_global, new[] {sender, e});
        // your custom code
    }
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