我该如何处理这个错误？

本文介绍了我该如何处理这个错误？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 29岁程序员，3月因学历无情被辞！ hi i有这个错误：hii have this error:Object reference not set to an instance of an object.Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.Source Error:Line 2420: ElseLine 2421: Throw exLine 2422: End IfLine 2423:Line 2424: FinallySource File: C:\Istg\Final version 941211\IstgVersions\IstgVersions\workflow\Pages\Compose.ascx.vb Line: 2422Stack Trace:[NullReferenceException: Object reference not set to an instance of an object.] IstgWebApp.clsWorkflowCompose.Page_Load(Object sender, EventArgs e) in C:\Istg\Final version 941211\IstgVersions\IstgVersions\workflow\Pages\Compose.ascx.vb:2422 System.Web.UI.Control.LoadRecursive() +71 System.Web.UI.Control.LoadRecursive() +190 System.Web.UI.Control.LoadRecursive() +190 System.Web.UI.Control.LoadRecursive() +190 System.Web.UI.Control.LoadRecursive() +190 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3178 ////// /////////////////// 我的vb代码在这里：///////////////////////my vb code is here:If Request.Params.Get("__EVENTTARGET") = "Confirm" Then Confirm() ElseIf Request.Params.Get("__EVENTTARGET") = "save" Then SaveDraft() ElseIf Request.Params.Get("__EVENTTARGET") = "ChangeEditor" Then LoadEditor() ElseIf Request.Params.Get("__EVENTTARGET") = "ddlDocumentTemplateRef_DropDown_IndexChange" Then ddlDocumentTemplateRef_IndexChanged() ElseIf Request.Params.Get("__EVENTTARGET") = "ddlGroup_DropDown_IndexChange" Then ddlGroup_IndexChanged() End If divScript.InnerHtml = "" Catch ex As Exception If ex.Message = "Could Not Open The Letter" Then Response.Write("<script>alert('اشکال در باز کردن نامه');</script>") Else Throw ex End If Finally End Try<pre lang="vb"> /////////////////// 感谢您的帮助 我尝试了什么： 我想解决这个问题。请帮我做那个///////////////////thanks for your helpWhat I have tried:i want to solve this problem. please help me to do that推荐答案这是我们被问到的最常见问题之一，也是我们最不能回答的问题，但你是最有能力回答你自己。 让我解释一下错误的含义：你试图使用变量，属性或方法返回值，但它包含null - 这意味着变量中没有类的实例。 它有点像一个口袋：你的衬衫里有一个口袋，用来握笔。如果你进入口袋并发现那里没有笔，你就不能在一张纸上签名 - 如果你尝试的话，你会得到非常有趣的外观！空口袋给你一个空值（这里没有笔！）所以你不能做任何你检索笔通常做的事情。它为什么空？这就是问题 - 可能是你今天早上离开家时忘了拿起你的笔，或者你昨晚把它拿到昨天的衬衫口袋里时可能会把笔留下来。 我们无法分辨，因为我们不在那里，更重要的是，我们甚至看不到你的衬衫，更不用说口袋里的东西了！ 回到计算机，你做了同样的事情，不知何故 - 我们看不到你的代码，更不用说运行它了，找不到包含null的东西。 但是你可以 - 而Visual Studio将在这里帮助你。在调试器中运行您的程序，当它失败时，VS将向您显示它发现问题的行。然后，您可以开始查看它的各个部分，以查看哪个值为null，并开始回顾代码以找出原因。因此，在包含错误行的方法的开头放置一个断点，然后从头再次运行程序。这一次，VS会在错误发生前停止，让你通过查看代码来查看你的价值来检查发生了什么。 但我们做不到那 - 我们没有您的代码，如果我们拥有它，我们不知道如何使用它，我们没有您的数据。所以尝试一下 - 看看你能找到多少信息！This is one of the most common problems we get asked, and it's also the one we are least equipped to answer, but you are most equipped to answer yourself.Let me just explain what the error means: You have tried to use a variable, property, or a method return value but it contains null - which means that there is no instance of a class in the variable.It's a bit like a pocket: you have a pocket in your shirt, which you use to hold a pen. If you reach into the pocket and find there isn't a pen there, you can't sign your name on a piece of paper - and you will get very funny looks if you try! The empty pocket is giving you a null value (no pen here!) so you can't do anything that you would normally do once you retrieved your pen. Why is it empty? That's the question - it may be that you forgot to pick up your pen when you left the house this morning, or possibly you left the pen in the pocket of yesterdays shirt when you took it off last night.We can't tell, because we weren't there, and even more importantly, we can't even see your shirt, much less what is in the pocket!Back to computers, and you have done the same thing, somehow - and we can't see your code, much less run it and find out what contains null when it shouldn't.But you can - and Visual Studio will help you here. Run your program in the debugger and when it fails, VS will show you the line it found the problem on. You can then start looking at the various parts of it to see what value is null and start looking back through your code to find out why. So put a breakpoint at the beginning of the method containing the error line, and run your program from the start again. This time, VS will stop before the error, and let you examine what is going on by stepping through the code looking at your values.But we can't do that - we don't have your code, we don't know how to use it if we did have it, we don't have your data. So try it - and see how much information you can find out!请检查第一行中的参数是否为null，如果它不为null则处理进一步的代码，否则做你想做的任何事情去做。 if（！String.IsNullorEmpty（Request.Params.Get（__ EVENTTARGET））应该根据空值检查。我认为它没有指出任何对象因此你的程序会抛出错误。你可以在处理之前使用Get获取的每个参数使用此代码行。 null引用错误是一个常见的错误。所以程序员应该总是检查空值。please check the parameter in the first line for null if it is not null then process the further code otherwise do whatever you want to do.if(!String.IsNullorEmpty(Request.Params.Get("__EVENTTARGET")) should be checked against null value. i think it is not pointing out any object so your program is throwing the error.you may use this code line for every parameter that you are getting using Get before processing .null reference error is a common error . so programmer should always have a check for null values . 这篇关于我该如何处理这个错误？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！