C#动态调用泛型类、泛型方法

在制作一个批量序列化工具时遇到了如下问题，在此记录一下，仅供参考。

主程序加载另一个程序集，将其中的所有类取出，然后对这些类分别调用泛型类或泛型方法。控制台程序解决方案如下：

• Main工程：提供Worker类进行数据操作，XMLTool<T>泛型类将数据集序列化为.xml文档，RootCollection<T>类封装数据集
  • Worker类

  　　     提供成员方法void DoWork<T>()、List<T> GetList<T>()、静态成员方法StaticDoWork<T>()，代码如下：

   1 public class Worker 2     { 3         public Worker() 4         { 5         } 6  7         public void DoWork<T>() 8         { 9             Type t = typeof(T);10             Console.WriteLine("Get Class: {0}", t.Name);11             PropertyInfo[] properties = t.GetProperties();12             foreach (PropertyInfo property in properties)13             {14                 Console.WriteLine("\tproperty.Name: " + property.Name + "\tproperty.MemberType: " + property.PropertyType);15             }16         }17 18         public static void StaticDoWork<T>()19         {20             Type t = typeof(T);21             Console.WriteLine("Get Class: {0}", t.Name);22             PropertyInfo[] properties = t.GetProperties();23             foreach (PropertyInfo property in properties)24             {25                 Console.WriteLine("\tproperty.Name: " + property.Name + "\tproperty.MemberType: " + property.PropertyType);26             }27         }28 29         public List<T> GetList<T>()30         {31             Console.WriteLine("Generate List for [{0}]", typeof(T).Name);32             return new List<T>() 33             { 34                 Activator.CreateInstance<T>(), 35                 Activator.CreateInstance<T>() 36             };37         }38     }

• XMLTool<T>类

   1publicclass XMLTool<T> 2     { 3publicstaticvoid XmlSerialize_Save(List<T> needSerializedList, string xmlDirPath, string xmlFileName) 4         { 5             RootCollection<T> collection = new RootCollection<T>(); 6             collection.ItemList = needSerializedList; 7if (!Directory.Exists(xmlDirPath)) 8                 Directory.CreateDirectory(xmlDirPath); 9using (System.IO.FileStream stream = new System.IO.FileStream(xmlFileName, System.IO.FileMode.Create))10             {11                 System.Xml.Serialization.XmlSerializer serializer = new System.Xml.Serialization.XmlSerializer(collection.GetType());12                 serializer.Serialize(stream, collection);13             }14         }15     }

• RootCollection<T>类：

   1     [Serializable] 2     public class RootCollection<T> 3     { 4         public RootCollection() 5         { 6             itemList = new List<T>(); 7         } 8  9         private List<T> itemList;10 11         public List<T> ItemList12         {13             get { return itemList; }14             set { itemList = value; }15         }16     }

• MockClassLib工程：提供BaseEntity、Apple、Cat和Person类
• BaseEntity类：抽象类，负责初始化类成员

   1     public abstract class BaseEntity 2     { 3         public BaseEntity() 4         { 5             InitiaWithNull(); 6         } 7 8         private void InitiaWithNull() 9         {10             Type type = this.GetType();11             PropertyInfo[] properties = type.GetProperties();12             string[] PropNames = new string[properties.Length];13             Dictionary<string, PropertyInfo> PropNameToInfo = new Dictionary<string, PropertyInfo>();14             for (int i = 0; i < properties.Length; i++)15             {16                 PropNames[i] = properties[i].Name;17                 PropNameToInfo.Add(PropNames[i], properties[i]);18             }1920             foreach (string propname in PropNames)21             {22                 string proptype = PropNameToInfo[propname].PropertyType.Name;2324                 object value = null;25                 if (NullValue.Keys.Contains(proptype))26                     value = NullValue[proptype];2728                 type.GetProperty(propname).SetValue(this, value, null);29             }30         }3132         private static readonly Dictionary<string, object> NullValue = new Dictionary<string, object>() 33             { 34                 { "String", String.Empty }, 35                 { "DateTime", DateTime.MinValue},36                 { "Decimal", Decimal.MinValue}37             };38     }

• Apple、Cat和Person类：测试类，继承于BaseEntity

   1     public class Apple : BaseEntity 2     { 3        public string Color { get; set; } 4     } 5 6     public class Cat : BaseEntity 7     { 8        public string Type { get; set; } 9     }1011     public class Person : BaseEntity12     {13        public int ID { get; set; }14        public string Name { get; set; }15     }

Main工程的Program的Main方法中，一般情况下，调用Worker的泛型方法来处理测试类的话，可以写为：

Worker worker = new Worker();

worker.DoWork<Apple>();

worker.DoWork<Cat>();

worker.DoWork<Person>();

但是，如果MockClassLib中需要处理的类型非常多时，这样显示调用必然是不灵活的，应当怎样向泛型方法DoWork<T>()的尖括号中动态传入类型呢？

考虑代码：

            //Load assembly            Assembly mockAssembly = Assembly.LoadFrom("MockClassLibrary.dll");            Type[] typeArray = mockAssembly.GetTypes();

//Create instance of Worker                      Worker worker = new Worker();            foreach(Type curType in typeArray)            {                  worker.DoWork<curType>();   //Error            }

可以看到，Type类型的实例是无法直接传入泛型方法的尖括号中的，T要求显式指明类型名。

下面通过反射方式来获取泛型方法，并创建特定类型的泛型方法。

• 对于非静态方法：public void DoWork<T>()

对于非静态方法，调用MethodInfo.Invoke(object, object[])时，第一个参数需要指明泛型方法的所有者（即这里创建的worker对象），第二个参数为泛

型方法的参数列表，DoWork<T>()没有输入参数，所以设为null

//Create an instance of WorkerWorker worker = new Worker();       

//Get type of WorkerType workerType = typeof(Worker);

//Get Generic MethodMethodInfo doWorkMethod = workerType.GetMethod("DoWork");

//Invoke DoWork<T> with different Typeforeach (Type curType in typeArray){    if (curType.IsClass && !curType.IsAbstract)//Filter BaseEntity    {        MethodInfo curMethod = doWorkMethod.MakeGenericMethod(curType);        curMethod.Invoke(worker, null);//Member method，use instance    }}

• 对于静态方法：public static void StaticDoWork<T>()

不同于非静态方法，这里直接反射的类静态方法，所以Invoke()的第一个参数设为null

//Get type of WorkerWorker worker = new Worker();

//Get Generic MethodMethodInfo staticDoWorkMethod = workerType.GetMethod("StaticDoWork");

//Invoke StaticDoWork<T>foreach (Type curType in typeArray){    if (curType.IsClass && !curType.IsAbstract)    {        MethodInfo curMethod = staticDoWorkMethod.MakeGenericMethod(curType);        curMethod.Invoke(null, null);//Static method    }}

• 对于有返回值的非静态方法：public List<T> GetList()

如同动态调用DoWork<T>()方法一样，只是在处理返回值时，可以使用下面的方法

1 IList tempList = (IList)curMethod.Invoke(worker, null);2 //Or3 IEnumerable tempList = (IEnumerable)curMethod.Invoke(worker, null);

• 对于泛型类：XMLTool<T>

下面要使用泛型类XMLTool<T>的静态方法public static void XmlSerialize_Save(List<T> list, string dirPath, string fileName)方法。

首先应通过反射构造出指定类型的泛型类XMLTool<T>，再反射出其中的XmlSerialize_Save方法并使用。

 1 //Use Generic Class 2 Type xmlToolType = typeof(XMLTool<>).MakeGenericType(curType); 3  4 //Get method 5 MethodInfo saveMethod = xmlToolType.GetMethod("XmlSerialize_Save"); 6  7 //Invoke 8 saveMethod.Invoke 9 (10     null, //Static method11     new object[] { resultList, @"c:\", @"c:\Test_" + curType.Name + ".xml" }

12 );

Program-->Main()方法的全部代码：

 1 namespace RetrieveUnknownClass 2 { 3     class Program 4     { 5         static void Main(string[] args) 6         { 7             //Load assembly 8             Assembly mockAssembly = Assembly.LoadFrom("MockClassLibrary.dll"); 9             Type[] typeArray = mockAssembly.GetTypes();10 11             //Create instance of Worker          12             Type workerType = typeof(Worker);13             Worker worker = new Worker();14 15             #region Member method16 17             Console.WriteLine(">>>>>>>>>Use Generic Method：");18             MethodInfo doWorkMethod = workerType.GetMethod("DoWork");19 20             //Invoke DoWork<T>21             foreach (Type curType in typeArray)22             {23                 if (curType.IsClass && !curType.IsAbstract)24                 {25                     MethodInfo curMethod = doWorkMethod.MakeGenericMethod(curType);26                     curMethod.Invoke(worker, null);//Member method，use instance27                 }28             }29 30             #endregion31 32             #region Static method33 34             Console.WriteLine("\r\n>>>>>>>>>Use Static Generic Method：");35             MethodInfo staticDoWorkMethod = workerType.GetMethod("StaticDoWork");36 37             //Invoke StaticDoWork<T>38             foreach (Type curType in typeArray)39             {40                 if (curType.IsClass && !curType.IsAbstract)41                 {42                     MethodInfo curMethod = staticDoWorkMethod.MakeGenericMethod(curType);43                     curMethod.Invoke(null, null);//Static method44                 }45             }46 47             #endregion48 49             #region Get A List & Serialize It to Xml File With Generic 50 51             Console.WriteLine("\r\n>>>>>>>>>Get List By Generic Method：");52             MethodInfo getListMethod = workerType.GetMethod("GetList");53 54             foreach (Type curType in typeArray)55             {56                 if (curType.IsClass && !curType.IsAbstract)57                 {58                     MethodInfo curMethod = getListMethod.MakeGenericMethod(curType);59                     //Generate List60                     IList resultList = (IList)curMethod.Invoke(worker, null);61                     //Show List62                     ShowList(resultList);63                     //Use Generic Class64                     Type xmlToolType = typeof(XMLTool<>).MakeGenericType(curType);65                     MethodInfo saveMethod = xmlToolType.GetMethod("XmlSerialize_Save");66 67                     saveMethod.Invoke68                         (69                             null, //Static method70                             new object[] { resultList, @"c:\", @"c:\Test_" + curType.Name + ".xml" }71                         );72                 }73             }74             75             Console.WriteLine("Serialization Completed...\r\n");76             #endregion77         }78 79         public static void ShowList(IList list)80         {81             Console.WriteLine("Type of list: {0}\r\nCount of current list: {1}\r\nType of item in list: {2}\r\n", 82                 list.GetType(), 83                 list.Count, 84                 list[0].GetType());85         }86     }87 }

原文地址：https://www.cnblogs.com/smiler/p/10177356.html