从供应商的Global.asax继承Global.asax时，Application_Start不会触发
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，但我没有其源代码。我通过继承供应商的Global类来做到这一点。下面是代码(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，我没有源代码来改变这一点)：
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);
}
}我在站点的global.asax文件中引用代码，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。我可以从Session_Start写事件和写出文本文件，但是Application_Start，nadda。
有人知道这是怎么回事吗？
编辑：
以下是实现Jan的建议后的代码:公共类CustomGlobal : HttpApplication {私有只读全局_global；私有只读MethodInfo _appStartInfo；私有只读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(对象发送者，EventArgs e) +28
TargetInvocationException:调用的目标引发了异常。System.RuntimeMethodHandle._InvokeMethodFast(IRuntimeMethodInfo方法，对象目标，区域性参数，SignatureStruct& sig，签名结构，签名typeOwner) +0 System.Reflection.RuntimeMethodInfo.Invoke(Object方法，对象目标，签名参数，签名签名，MethodAttributes methodAttributes，布尔值) +72 System.Reflection.RuntimeMethodInfo.Invoke(Object obj，typeOwner Object[]，MethodAttributes methodAttributes，RuntimeType typeOwner) +251 System.Reflection.RuntimeMethodInfo.Invoke(Object obj，，绑定器绑定器，参数，RuntimeType ) +28 ( Object obj，对象对象，CultureInfo skipVisibilityChecks，Boolean skipVisibilityChecks)Object[]参数) +19 CustomGlobal.Application_Start(对象发送者，EventArgs e) +231
HttpException (0x80004005)：调用的目标引发了异常。System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext上下文，应用上下文) +9239341 System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr状态，MethodInfo[]上下文，appContext处理程序)+9239341 System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr状态，MethodInfo[]处理程序，IntPtr appContext，HttpContext上下文) +194 HttpApplication appContext，HttpContext上下文) +339 System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext，HttpContext appContext) +253
HttpException (0x80004005)：调用的目标引发了异常。System.Web.HttpRuntime.FirstRequestInit(HttpContext上下文) +9157968 System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext上下文) +97 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr，HttpContext上下文) +256
回答 1
Stack Overflow用户
发布于 2014-09-17 02:11:17
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。
解决方案可以是私有成员模式
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
}https://stackoverflow.com/questions/25873108
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