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问题描述
我正在尝试构建一个工厂类,该工厂类将为我提供不同DbContext的单例化实例。
I am trying to build a factory class that will feed me singleton-ized instances of different DbContexts.
主要思想是使 Dictionary< Type,DbContext> 将容纳我需要的所有实例,以及 GetDbContext(Type type)方法,该方法在字典并返回(如果已存在)。如果没有,则应该创建一个新的Type()并将其添加到相应的字典中。
The main idea is to have a Dictionary<Type,DbContext>that will hold all the instances I need , and a GetDbContext(Type type) method that looks up type in the dictionary and returns it if it already exists. If it doesn't it should create a new Type(), and add it to the corresponding dictionary.
我不知道该怎么做 contexts.Add(type,new type());
public class DbContextFactory { private readonly Dictionary<Type, DbContext> _contexts; private static DbContextFactory _instance; private DbContextFactory() { _contexts= new Dictionary<Type, DbContext>(); } public static DbContextFactory GetFactory() { return _instance ?? (_instance = new DbContextFactory()); } public DbContext GetDbContext(Type type) { if (type.BaseType != typeof(DbContext)) throw new ArgumentException("Type is not a DbContext type"); if (!_contexts.ContainsKey(type)) _contexts.Add(type, new type()); //<--THIS is what I have now Idea how to do return _contexts[type]; } }推荐答案
制作它是一种通用方法:
Make it a generic method:
public DbContext GetDbContext<T>() where T : new() { if (typeof(T).BaseType != typeof(DbContext)) throw new ArgumentException("Type is not a DbContext type"); if (!_contexts.ContainsKey(type)) _contexts.Add(typeof(T), new T()); return _contexts[type]; }更多推荐
如何动态实例化对象?
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