invalidoperationexception

问题 I'm debugging a simulation with many calculations in many Fortran files. I am used to seeing some floating point exceptions (-1.#QNB or 1.#QNAN) for errors that involve division by zero or operations that exceed the maximum size for floating point number. I'm assuming -1.#IO means invalid operation, but I'm not sure mathematically what would cause this and not QNB or QNAN or QINF. What would lead to the exception -1.#IO? 回答1: According to the IEEE 754 Standard for Floating Point Operations,

问题 class Program { static void Main(string[] args) { var dictionary = new Dictionary<string, int>() { {"1", 1}, {"2", 2}, {"3", 3} }; foreach (var s in dictionary.Keys) { // Throws the "Collection was modified exception..." on the next iteration // What's up with that? dictionary[s] = 1; } } } I completely understand why this exception is thrown when enumerating a list- it seems reasonable to expect that during enumeration, the Structure of the enumerated object does not change. However- does

问题 following is a code snippet: class xxx { public xxx(){} try { throw new Exception(InvalidoperationException); } catch(Exception x) { } catch(InvalidoperationException x) { } } can anyone tell which exception will raise here and what is the reason behind it. 回答1: Wow, lots of problems here. Where to start? That code won't compile. The try-catch block that you've defined is outside of any method, which is not allowed. You need to move it inside of a method. Never throw a method that you intend

问题 I am trying to play audio in my Silverlight for Windows Phone 7 app. I have an MP3 audio file with its build action set to resource. To play the sound, I use: SoundEffectInstance sfi = null; ... Stream source = Application.GetResourceStream(new Uri("/Bird Calls;component/Crow.mp3", UriKind.Relative)).Stream; Microsoft.Xna.Framework.Audio.SoundEffect effect = SoundEffect.FromStream(source); sfi = effect.CreateInstance(); sfi.Play(); This code throws a InvalidOperationException at the

问题 This is really getting annoying; or, to be honest, it became quite annoying a good while back. Programmatically removing items from a listbox should be pretty straightforward, yet it seems everything I try ends up the same: with an exception. This time it's "InvalidOperationException". In context (excerpt of log file): Date: 2/12/2015 7:15:17 PM Message: Reached frmMain.UpdateGUIAfterTableSend Date: 2/12/2015 7:15:17 PM Message: From frmMain.SendDeliveries(): InvalidOperationException; Inner

问题 I have multiple serial devices connected to my PC and I am working on a program that allows users select as many as ports they want and then the program will dynamically creates TabPage and adds them to TabControl . Each tab page will also have a multiline TextBox that will show the incoming data from the assigned serialport to it. Here is my code that tries to create these controls dynamically: private void AddSerialPort(string portName) { ActiveSerialPorts.Add(portName); if (

问题 I am using C# and WPF and am trying to slide an image strip along the screen. I am being honest, I got the code from some code sample on the Internet and took the parts I needed from it. public double ImageOffset { get { try { return (double)this.Dispatcher.Invoke( System.Windows.Threading.DispatcherPriority.Background, (DispatcherOperationCallback)delegate { return GetValue(ImageOffsetProperty); }, ImageOffsetProperty); } catch { return (double)this.GetValue(ImageOffsetProperty); } } set {

问题 I was following the tutorial on this page, about how to add roles to users programatically in C# MVC. However, when the code executes I get the following error: System.InvalidOperationException was unhandled by user code HResult=-2146233079 Message=UserId not found. Source=Microsoft.AspNet.Identity.Core StackTrace: at Microsoft.AspNet.Identity.UserManager`2.<AddToRoleAsync>d__83.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime

问题 I have the following code this.SafeUpdate(rate, Guid.Parse(import.myGuid), c => c.myGuid); SafeUpdate basically takes the parsed guid value and applies it to the myGuid property on the rate object. This works fine from my front end, but throws the "CLR detected..." error when run in a unit test. What's odd is the same statement for DateTime.Parse and int.Parse works fine. It just fails for Guid and decimals. I don't believe the error is with the parsing (it has the correct parsed value when

问题 I don't think I'm exceeding the MaxJsonLength, but I'm still getting "Error during serialization or deserialization using the JSON JavaScriptSerializer. The length of the string exceeds the value set on the maxJsonLength property". I checked to see how long the result is, and it's 25,000 rows. I checked the average length of each row by outputting a smaller result, and the average row is 48.5 characters long. 25,000 * 48.5 characters = 1,224,140 characters. MS says that maxJsonLength is in