For what it’s worth, a Dictionary is (conceptually) a hash table. If you meant “why do we use the Dictionary<TKey, TValue> class instead of the Hashtable class?”, then it’s an easy answer: Dictionary<TKey, TValue> is a generic type, Hashtable is not. That means you get type safety with Dictionary<TKey, TValue>, because you can’t insert any … Read more
The simplest way is an anonymous method passed into Label.Invoke: // Running on the worker thread string newText = “abc”; form.Label.Invoke((MethodInvoker)delegate { // Running on the UI thread form.Label.Text = newText; }); // Back on the worker thread Notice that Invoke blocks execution until it completes–this is synchronous code. The question doesn’t ask about asynchronous … Read more
One of the Roslyn engineers who specializes in understanding optimization of stack usage took a look at this and reports to me that there seems to be a problem in the interaction between the way the C# compiler generates local variable stores and the way the JIT compiler does register scheduling in the corresponding x86 … Read more
Apart from the apparent difference of having to declare the value at the time of a definition for a const VS readonly values can be computed dynamically but need to be assigned before the constructor exits.. after that it is frozen. const‘s are implicitly static. You use a ClassName.ConstantName notation to access them. There is … Read more
I usually go with something like the implementation given in Josh Bloch’s fabulous Effective Java. It’s fast and creates a pretty good hash which is unlikely to cause collisions. Pick two different prime numbers, e.g. 17 and 23, and do: public override int GetHashCode() { unchecked // Overflow is fine, just wrap { int hash … Read more
There are some good answers here. I would add to them the following points. What is the correct C# way of representing a data structure, which, “logically” (that is to say, “to the human mind”) is just a list of things with a few bells and whistles? Ask any ten non-computer-programmer people who are familiar … Read more
Yes you can use the GetValues method: var values = Enum.GetValues(typeof(Foos)); Or the typed version: var values = Enum.GetValues(typeof(Foos)).Cast<Foos>(); I long ago added a helper function to my private library for just such an occasion: public static class EnumUtil { public static IEnumerable<T> GetValues<T>() { return Enum.GetValues(typeof(T)).Cast<T>(); } } Usage: var values = EnumUtil.GetValues<Foos>();
Modify your constructor to the following so that it calls the base class constructor properly: public class MyExceptionClass : Exception { public MyExceptionClass(string message, string extrainfo) : base(message) { //other stuff here } } Note that a constructor is not something that you can call anytime within a method. That’s the reason you’re getting errors … Read more
The point of Dispose is to free unmanaged resources. It needs to be done at some point, otherwise they will never be cleaned up. The garbage collector doesn’t know how to call DeleteHandle() on a variable of type IntPtr, it doesn’t know whether or not it needs to call DeleteHandle(). Note: What is an unmanaged … Read more
What is the cause? Bottom Line You are trying to use something that is null (or Nothing in VB.NET). This means you either set it to null, or you never set it to anything at all. Like anything else, null gets passed around. If it is null in method “A”, it could be that method … Read more