通过反射调用類的方法,屬性,字段,索引器(2種方法)

Type是System.Reflection功能的根 (Root)，也是存取Metadata的主要方法. 使用Type的成員可以取得相關資訊,例如建構函式(Constructor),方法,字段,屬性和類別的事件,以及模組和部署類別的組件(Assembly). 3種取得Type的方法: 1.靜態方法 Type.GetType() 2.運算符 typeof() 3.實例的方法GetType Employee e=new Employee(); e.GetType() 在一般情況下我們调用的方法並传递给它们的参数,某些情况下可能希望根据用户操作动态调用方法. 通过Reflection命名空间 方法1是使用Type对象上的InvokeMember方法 方法2是使用MethodInfo对象上的Invoke方法 example: 先定義類Employee 其中有靜態屬性Data 實例屬性Name,ID 2個索引器 ///<summary> ///自定義類 ///</summary> publicclassEmployee { stringname; intid; ArrayListlist; staticintdata; //instance.ctor() publicEmployee(intid,Stringname) { this.name=name; this.id=id; list=newArrayList(); this.list.Add("001"); this.list.Add("002"); } //static.ctor() staticEmployee() { data=119; } publicoverridestringToString() { return"Id="+id.ToString()+",Name="+name; } //instanceMethod"add" publicstringadd(stringkey1,stringkey2) { stringresult=key1+key2; returnresult; } //staticMethod"add" publicstaticstringadd(stringkey1,stringkey2,stringkey3) { returnkey1+key2+key3; } publicstringName { get { returnname; } set { name=value; } } publicintID { get { returnid; } set { id=value; } } publicstaticintData { get { returndata; } set { data=value; } } ///<summary> ///byindex ///</summary> publicstringthis[intindex] { get { returnlist[index].ToString(); } set { list[index]=value; } } ///<summary> ///byvalue ///</summary> publicstringthis[stringvalues] { set { this[list.IndexOf(values)]=value; } } } 動態調用: 定義變量 stringresult=String.Empty; inti; Typet=typeof(Employee); Employeee=newEmployee(1000,"no1000"); 方法1是使用Type对象上的InvokeMember方法: 先動態調用類Employee的實例方法ToString InvokeMember方法的第一個參數是要調用的方法名稱 第2個參數是位枚舉,代表搜尋的方式 第四個參數是要調用的對象,要是靜態的就用null 第五個參數是要傳送給ToString的數值,由於ToString方法是無參方法,這裡我們送一個空數組new object[]{} 1//callinstanceMethod"ToString" 2result=(typeof(Employee).InvokeMember("ToString", 3BindingFlags.InvokeMethod, 4null, 5e, 6newobject[]{})).ToString(); 7Console.WriteLine("instanceMethod'ToString'result={0}",result); 8 再動態調用類Employee的實例方法add,靜態方法add 注意InvokeMember方法的第5個參數代表的是要傳送給add方法的數值 第8個參數代表的是add方法的參數名稱 //callinstanceMethod"add" result=typeof(Employee).InvokeMember("add", BindingFlags.InvokeMethod, null, e, newobject[]{"o1","o2"}, null, null, newstring[]{"key1","key2"}).ToString(); Console.WriteLine("instanceMethod'add'result={0}",result); //callstaticMethod"add" result=typeof(Employee).InvokeMember("add", BindingFlags.InvokeMethod|BindingFlags.Static|BindingFlags.Public, null, null, newobject[]{"o1","o2","o3"}, null, null, newstring[]{"key1","key2","key3"}).ToString(); Console.WriteLine("staticMethod'add'result={0}",result); Console.WriteLine(); 再修改靜態屬性Data,把它從119修改為911 1//callstaticProperty 2i=(int)typeof(Employee).InvokeMember("Data", 3BindingFlags.GetProperty|BindingFlags.Public|BindingFlags.Static, 4null, 5null, 6newobject[]{}); 7Console.WriteLine("staticProperty'Data'={0}",i); 8 9//updatestaticProperty 10typeof(Employee).InvokeMember("data", 11BindingFlags.SetField|BindingFlags.NonPublic|BindingFlags.Static, 12null, 13null, 14newobject[]{911}); 15Console.WriteLine("updatestaticProperty"); 16 17//callstaticProperty 18i=(int)typeof(Employee).InvokeMember("Data", 19BindingFlags.GetProperty|BindingFlags.Public|BindingFlags.Static, 20null, 21null, 22newobject[]{}); 23Console.WriteLine("againcallstaticProperty'Data'={0}",i); 24Console.WriteLine(); 25 再修改實例屬性Name,把它從no 1000修改為w 1//readinstanceProperty 2result=typeof(Employee).InvokeMember("Name", 3BindingFlags.GetProperty, 4null, 5e, 6newobject[]{}).ToString(); 7Console.WriteLine("instanceProperty'Name'={0}",result); 8 9//updateinstanceproperty 10typeof(Employee).InvokeMember("name", 11BindingFlags.SetField|BindingFlags.NonPublic|BindingFlags.Instance, 12null, 13e, 14newobject[]{"w"}); 15Console.WriteLine("updateinstanceproperty"); 16 17//againcallreadinstanceProperty 18result=typeof(Employee).InvokeMember("Name", 19BindingFlags.GetProperty, 20null, 21e, 22newobject[]{}).ToString(); 23Console.WriteLine("againcallinstanceProperty'Name'={0}",result); 24Console.WriteLine(); 25 再修改索引器,把索引器的第2個(index[1])內容修改為222 注意修改索引器的InvokeMember方法,第5個參數的數組new object[]{"002","222"} 将要设置元素的索引值放在对象数组的第一个元素中,将要设置的值作为第二个元素 1//callindex[1] 2result=typeof(Employee).InvokeMember("Item", 3BindingFlags.GetProperty, 4null, 5e, 6newobject[]{1}).ToString(); 7Console.WriteLine("index[1]={0}",result); 8 9//updateindex[1] 10typeof(Employee).InvokeMember("Item", 11BindingFlags.SetProperty, 12null, 13e, 14newobject[]{"002","222"}); 15Console.WriteLine("updateindex[1]"); 16 17//againcallindex[1] 18result=typeof(Employee).InvokeMember("Item", 19BindingFlags.GetProperty, 20null, 21e, 22newobject[]{1}).ToString(); 23 24Console.WriteLine("againcallindex[1]={0}",result); 25Console.WriteLine(); 26 方法2是使用MethodInfo对象上的Invoke方法: 1//callInstanceMethod'add' 2MethodInfomethodInfo1=t.GetMethod("add",BindingFlags.Instance|BindingFlags.Public); 3//InstanceMethod,firstparameterisoneInstance 4result=methodInfo1.Invoke(newEmployee(1,""),newobject[]{"key1","key2"}).ToString(); 5Console.WriteLine("callInstanceMethod'add'result={0}",result); 6 7//callStaticMethod'add' 8MethodInfomethodInfo2=t.GetMethod("add",BindingFlags.Static|BindingFlags.Public); 9//StaticMethod,firstparameterisNull 10result=methodInfo2.Invoke(null,newobject[]{"key1","key2","key3"}).ToString(); 11Console.WriteLine("callStaticMethod'add'result={0}",result); 12 結果圖片: