nullreferenceexception

问题 I have a problem in a Linq-Where method. I get a NullReferenceException in a where clause, which should not happen because C# should use short-circuiting and the second operations hould not be executed: If Item is null, Item.State == ... should not be called, because the condition is already true (short-circuiting). But it seems, that short-circuiting does not working in this case. Does anyone else had and solved this problem? Thank you! Edit : In the end, the connectionList should not

问题 I am using a SWF(accueil) inside another SWF(ranchleblanc_fr) and this causes the error 1009 to appear: TypeError: Error #1009: Cannot access a property or method of a null object reference. at accueil_fla::MainTimeline/frame1()" The first SWF has a particle effect in it and it won't start when I first load the page. If i click on any button of the main page and return to the accueil page, the effect works. But if I click on another button again, I get another error 1009, but this time it

问题 I am running some .NET .dll s on Windows Server 2012 . The .NET assemblies were compiled from C# code on OS X with Xamarin 4.0 . (yeah I know weird setup- but I am a game developer) In general they run perfectly, but when it comes to inspecting Exception information, it's not so good. I am trying to pull info out of an Exception object, but it's all empty. I also tried copying the .mdb files along with the .dll s, and made sure I was building in Debug , and with debug symbols. For example

问题 I have a strange error, which has started suddenly and which is driving me crazy. In my C# application, I am doing some heavy mathematical calculations and for that purpose, I am using CenterSpace's NMath library. Recently, when I started my application from inside Visual Studio 2015 in order to debug it, the application started to crash because of NullReferenceExceptions in NMath.dll, whenever I call an NMath library method (and another library which we have written, as well). In order to

问题 My App wouldn't delete the save files on the loading page in the isolated storage. The codes for the delete and the ViewDiskModel.cs class are below: LoadingPage.cs private void button2_Click(object sender, RoutedEventArgs e) { ViewDiskModel model = lstBox1.DataContext as ViewDiskModel; int m_iSelectedLoad = lstBox1.SelectedIndex; if (m_iSelectedLoad >= 0) { model.DeleteSelectedFiles.Execute(null); } MessageBox.Show("Files Successfully Deleted"); } ViewDiskModel.cs: public class FileItem :

问题 I am making a simple Program which searches for a particular Name in a set of files.I have around 23 files to go through. To achieve this I am using StreamReader class, therefore, to write less of code, I have made a List<StreamReader> FileList = new List<StreamReader>(); list containing elements of type StreamReader and my plan is to iterate over the list and open each file: foreach(StreamReader Element in FileList) { while (!Element.EndOfStream) { // Code to process the file here. } } I

问题 I use crystal report to implement reporting in my c# windows application.I create a form to show print preview of Report.I use following code to show preview: private ReportDocument _reportDocument; public CrystalReportPrintPreviewForm(ReportDocument reportDocument) { InitializeComponent(); _reportDocument = reportDocument; } private void CrystalReportPrintPreviewForm_Load(object sender, EventArgs e) { if(_reportDocument!=null) crystalReportViewer1.ReportSource = _reportDocument; } And also i

问题 I am trying to create link labels dynamically using foreach . I am setting the text of each linklabel to a string which is stored in flatestgames string array and whose links are stored in flatestlinks string array. But it is throwing a null reference exception at the line flg[i].Text = s though s is not set to null. Please help me out. Below is the code snippet: if (!(flatestgames == null || flatestgames.Length < 1)) { i = 0; LinkLabel[] flg = new LinkLabel[10]; foreach (string s in

问题 A week ago, we had a working project. The following worked, without a problem on my machine (Window 8 developing in VisualStudio 2010) KinectSensor sensor = KinectSensor.KinectSensors[0]; public KinectController() { sensor.SkeletonFrameReady += runtime_SkeletonFrameReady; sensor.ColorStream.Enable(); sensor.SkeletonStream.Enable(); sensor.Start(); } This worked no problems. When my teammate pulled this down from an SVN, it broke, giving a null reference exception on ColorStream.Enable().

问题 So I track different users access through GUID. It has worked great up until now and I dont understand why its failing. I am assigning the variable, then I check for null, then run the code, and then it throws the nullreferenceexception error. Here is the code: if (String.IsNullOrEmpty(Session["GUID"] as string)) { Server.Transfer("~/index.aspx", true); } else { GUID = Session["GUID"].ToString(); if (!String.IsNullOrEmpty(GUID)) { itemID = (int)aooDB_Items.SelectItemID(GUID); } } The