反射(Reflection)有下列用途:
- 它允許在運行時查看特性(attribute)信息。
- 它允許審查集合中的各種類型,以及實例化這些類型。
- 它允許延遲綁定的方法和屬性(property)。
- 它允許在運行時創建新類型,然後使用這些類型執行一些任務。
1.查看特性:
namespace test
{
class Program
{
static void Main(string[] args)
{
System.Reflection.MemberInfo info = typeof(Test);
object[] attributes = info.GetCustomAttributes(true);
for (int i = 0; i < attributes.Length;i++ )
{
DebugInfo debuginfo = (DebugInfo)attributes[i];
Console.WriteLine("Develper:{0}\nDate:{1}\nMessage:{2}"
,debuginfo.Developer,debuginfo.Date,debuginfo.Message);
}
Console.ReadKey();
}
}
[AttributeUsage(AttributeTargets.Class)]
public class DebugInfo:Attribute //自定義特性
{
private string developer;
private string date;
private string message;
public string Developer { get { return developer; } }
public string Date { get { return date; } }
public string Message { get { return message; } }
public DebugInfo(string de,string da,string me)
{
this.developer = de;
this.date = da;
this.message = me;
}
}
[DebugInfo("menghan","2018/4/8","這是一個測試用例")]
public class Test
{
}}
2.獲取類型信息
namespace test
{
class Program
{
static void Main(string[] args)
{
Type type = typeof(Test1);
Console.WriteLine("類名:{0}\n類全名:{1}\n命名空間:{2}\n程序集:{3}\n模塊:{4}\n基類:{5}\n類的公共成員",
type.Name, type.FullName, type.Namespace, type.Assembly, type.Module, type.BaseType);
MemberInfo[] memberInfos = type.GetMembers();//得到所有公共成員
foreach(var m in memberInfos)
{
Console.WriteLine("{0}:{1}", m.MemberType, m);
}
Console.ReadKey();
}
}
public class Test1
{
public string member;
public void Mathod() { }
public int Property { get; set; }
}}
3.反射調用方法、屬性
namespace test
{
class Program
{
static void Main(string[] args)
{
System.Reflection.Assembly ass = Assembly.LoadFrom(@"C:\Users\Administrator\documents\visual studio 2013\Projects\test\test\bin\Debug\test.exe"); //加載DLL
System.Type t = ass.GetType("test.Test1");//獲得類型
string name = typeof(Test1).AssemblyQualifiedName;
System.Type t1 = Type.GetType(name);
System.Type t2 = typeof(Test1);
object o = System.Activator.CreateInstance(t);//創建實例
Test1 test1 = (Test1)o; test1.Mathod("測試反射機制");
System.Reflection.MethodInfo mi = t.GetMethod("Mathod");//獲得方法(只能獲得公共方法)
mi.Invoke(o, new object[] { "alert('測試反射機制')" });//調用方法
System.Reflection.PropertyInfo pi = t.GetProperty("Property");
pi.SetValue(o, 1000);//設置屬性
Console.WriteLine("屬性:" + pi.GetValue(o));//獲得屬性
Console.ReadKey();
}
}
public class Test1
{
public string member;
public void Mathod(string message) {
Console.WriteLine(message);
}
public int Property { get; set; }
}}
4.利用反射實現工廠模式
namespace test
{
class Program
{
static void Main(string[] args)
{
string typename = typeof(Test2).AssemblyQualifiedName;
ITest itest = TestFactory.Create<Test2>(typename);
itest.DoSomething();
Console.ReadKey();
}
}
public static class TestFactory
{
public static T Create<T>(string typename)
{
return (T)Activator.CreateInstance(Type.GetType(typename));
}
}
public interface ITest
{
void DoSomething();
}
public class Test2:ITest
{
public void DoSomething()
{
Console.WriteLine("測試用例");
}
}}