generics

问题 For level order traversal why does this exception occur? Following exception occurs: Cannot implicitly convert type ' System.Collections.Generic.List<System.Collections.Generic.List<int>> ' to ' System.Collections.Generic.IList<System.Collections.Generic.IList<int>> '. An explicit conversion exists (are you missing a cast?) public IList<IList<int>> LevelOrder(TreeNode root) { var result = new List<List<int>>(); var que = new Queue<TreeNode>(); //if(root==null) return result; que.Enqueue(root)

问题 For level order traversal why does this exception occur? Following exception occurs: Cannot implicitly convert type ' System.Collections.Generic.List<System.Collections.Generic.List<int>> ' to ' System.Collections.Generic.IList<System.Collections.Generic.IList<int>> '. An explicit conversion exists (are you missing a cast?) public IList<IList<int>> LevelOrder(TreeNode root) { var result = new List<List<int>>(); var que = new Queue<TreeNode>(); //if(root==null) return result; que.Enqueue(root)

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Why doesn’t Java allow generic subclasses of Throwable? I'm trying to make a regular RuntimeException inside a generic class like this: public class SomeGenericClass<SomeType> { public class SomeInternalException extends RuntimeException { [...] } [...] } This piece of code gives me an error on the word RuntimeException saying The generic class SomeGenericClass<SomeType>.SomeInternalException may not subclass

问题 I have three classes; Stamp, Letter and Parcel that implement an interface IProduct and they also have some of their own functionality. public interface IProduct { string Name { get; } int Quantity { get; set; } float Amount { get; } } public class Stamp : IProduct { public string Name { get { return "Stamp"; } } public int Quantity { get; set; } public float Amount { get; set; } public float UnitPrice { get; set; } } public class Letter : IProduct { public string Name { get { return "Letter"

问题 I have three classes; Stamp, Letter and Parcel that implement an interface IProduct and they also have some of their own functionality. public interface IProduct { string Name { get; } int Quantity { get; set; } float Amount { get; } } public class Stamp : IProduct { public string Name { get { return "Stamp"; } } public int Quantity { get; set; } public float Amount { get; set; } public float UnitPrice { get; set; } } public class Letter : IProduct { public string Name { get { return "Letter"

问题 I have an object which I must validate values off the problem, some of the attributes of the Objects are arrays of custom objects. Such that it will involve some boring down into the individual elements of the array. Excuting the getters for each element such as: AttribGrp[] x = Object.getAttribGrp() x[i].getSomeValue() It is this I need to get to. I have been extracted the data using an Enum with the list of the attributes In the following manner. public String getAttribValueAsString

问题 Say I have the following class: public class General<T> { } And I want to find out if an object is of that type. I know I can use reflection to find out whether the object is of that generic type with Type.GetGenericTypeDefinition , but I want to avoid that. Is it possible to do something like obj is General<T> , or obj.GetType().IsAssignableFrom(typeof(General<T>)) ? I'm quite surprised that I couldn't find a similar question, although I may have used wrong keywords in my searches. 回答1: You

问题 Say I have the following class: public class General<T> { } And I want to find out if an object is of that type. I know I can use reflection to find out whether the object is of that generic type with Type.GetGenericTypeDefinition , but I want to avoid that. Is it possible to do something like obj is General<T> , or obj.GetType().IsAssignableFrom(typeof(General<T>)) ? I'm quite surprised that I couldn't find a similar question, although I may have used wrong keywords in my searches. 回答1: You

问题 I am dealing with a WeChat project that post XML message to my server. The message could be any one of several types. Hence I first deserialize the message to corresponding object with a base "WxMessage", and then return the object to a dispatcher, which will find out a correct message handler to handle the message. The handlers, corresponding to each type of messages, were registered to the DependencyInjection of Asp.net core 2.1 with a IWxMessageHandler<> interface. services.AddScoped

问题 I'm trying to essentially copy any list items in fileManifest but only those that don't contain in any of the items from exclusionFilters to a newly initialized list. I haven't figured out an elegant way to do this other than a nested foreach loop. Does someone by chance have a better solution for this problem? Maybe LINQ ? var fileManifest = new List<string>() { @"C:\Test\Directory1\File1.xml", @"C:\Test\Directory1\File2.xml", @"C:\Test\Directory1\Directory2\File1.xml", }; var