nullreferenceexception

问题 I want to access Hero.class variable "aspect" from laserController.class, but I receive an error message : NullReferenceException: Object reference not set to an instance of an object . Hero.class using UnityEngine; using System.Collections; public class Hero : MonoBehaviour { public float aspect = 0.1f; void Update () { } } laserController.class using UnityEngine; using System.Collections; public class laserController : MonoBehaviour { public float health = 0f; //public float aspect = 0.1f;

问题 I want to access Hero.class variable "aspect" from laserController.class, but I receive an error message : NullReferenceException: Object reference not set to an instance of an object . Hero.class using UnityEngine; using System.Collections; public class Hero : MonoBehaviour { public float aspect = 0.1f; void Update () { } } laserController.class using UnityEngine; using System.Collections; public class laserController : MonoBehaviour { public float health = 0f; //public float aspect = 0.1f;

问题 I have a class, clsPerson, that looks like this: public class clsPerson { public string FirstName; public string LastName; public string Gender; public List<Book> Books; } I have another class, Book, that looks like this: public class Book { public string Title; public string Author; public string Genre; public Book(string title, string author, string genre) { this.Title = title; this.Author = author; this.Genre = genre; } } I wrote a program to test serializing an object into XML. Here's

问题 For a couple of days I am working on a WebBrowser based webscraper. After a couple of prototypes working with Threads and DocumentCompleted events, I decided to try and see if I could make a simple, easy to understand Webscraper. The goal is to create a Webscraper that doesn't involve actual Thread objects. I want it to work in sequential steps (i.e. go to url, perform action, go to other url etc. etc.). This is what I got so far: public static class Webscraper { private static WebBrowser _wb

问题 For a couple of days I am working on a WebBrowser based webscraper. After a couple of prototypes working with Threads and DocumentCompleted events, I decided to try and see if I could make a simple, easy to understand Webscraper. The goal is to create a Webscraper that doesn't involve actual Thread objects. I want it to work in sequential steps (i.e. go to url, perform action, go to other url etc. etc.). This is what I got so far: public static class Webscraper { private static WebBrowser _wb

问题 I've had an asp.net website running live on our intranet for a couple of weeks now. I just got an email from my application_error emailer method with an unhandled exception. Here it is (I've cleaned up some of the paths to make it better displayed) Exception : Object reference not set to an instance of an object. Stack Trace : at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value) at

问题 I've had an asp.net website running live on our intranet for a couple of weeks now. I just got an email from my application_error emailer method with an unhandled exception. Here it is (I've cleaned up some of the paths to make it better displayed) Exception : Object reference not set to an instance of an object. Stack Trace : at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value) at

问题 I've had an asp.net website running live on our intranet for a couple of weeks now. I just got an email from my application_error emailer method with an unhandled exception. Here it is (I've cleaned up some of the paths to make it better displayed) Exception : Object reference not set to an instance of an object. Stack Trace : at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value) at

问题 I've had an asp.net website running live on our intranet for a couple of weeks now. I just got an email from my application_error emailer method with an unhandled exception. Here it is (I've cleaned up some of the paths to make it better displayed) Exception : Object reference not set to an instance of an object. Stack Trace : at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value) at

问题 Could someone explain why I obtain a NullReference Exception to an objet that I initialized as New List(Of)?? Module Module1 ' MAIN ================================= Sub Main() Console.Clear() Console.WriteLine("Creating Bar") Dim myBar As New Bar() Console.ReadLine() End Sub End Module Class Foo Public Overridable Property Test As String Public Sub New() Me.Test = "hello" End Sub End Class Class Bar Inherits Foo Private _MyString As New List(Of String) Public Sub New() MyBase.New() End Sub