Object.GetType Object.GetType Object.GetType Object.GetType Method

Definition

获取当前实例的 Type Gets the Type of the current instance.

public:
 Type ^ GetType();
public Type GetType ();
member this.GetType : unit -> Type
Public Function GetType () As Type

Returns

当前实例的准确运行时类型。 The exact runtime type of the current instance.

Examples

下面的代码示例演示GetType返回当前实例的运行时类型。The following code example demonstrates that GetType returns the runtime type of the current instance.

using namespace System;

public ref class MyBaseClass {};

public ref class MyDerivedClass: MyBaseClass{};

int main()
{
   MyBaseClass^ myBase = gcnew MyBaseClass;
   MyDerivedClass^ myDerived = gcnew MyDerivedClass;
   Object^ o = myDerived;
   MyBaseClass^ b = myDerived;
   Console::WriteLine( "mybase: Type is {0}", myBase->GetType() );
   Console::WriteLine( "myDerived: Type is {0}", myDerived->GetType() );
   Console::WriteLine( "object o = myDerived: Type is {0}", o->GetType() );
   Console::WriteLine( "MyBaseClass b = myDerived: Type is {0}", b->GetType() );
}

/*

This code produces the following output.

mybase: Type is MyBaseClass
myDerived: Type is MyDerivedClass
object o = myDerived: Type is MyDerivedClass
MyBaseClass b = myDerived: Type is MyDerivedClass 

*/
using System;

public class MyBaseClass {
}

public class MyDerivedClass: MyBaseClass {
}

public class Test 
{
   public static void Main() 
   {
      MyBaseClass myBase = new MyBaseClass();
      MyDerivedClass myDerived = new MyDerivedClass();
      object o = myDerived;
      MyBaseClass b = myDerived;

      Console.WriteLine("mybase: Type is {0}", myBase.GetType());
      Console.WriteLine("myDerived: Type is {0}", myDerived.GetType());
      Console.WriteLine("object o = myDerived: Type is {0}", o.GetType());
      Console.WriteLine("MyBaseClass b = myDerived: Type is {0}", b.GetType());
   }
}
// The example displays the following output:
//    mybase: Type is MyBaseClass
//    myDerived: Type is MyDerivedClass
//    object o = myDerived: Type is MyDerivedClass
//    MyBaseClass b = myDerived: Type is MyDerivedClass 
' Define a base and a derived class.
Public Class MyBaseClass
End Class 

Public Class MyDerivedClass : Inherits MyBaseClass
End Class 

Public Class Test
    Public Shared Sub Main() 
        Dim base As New MyBaseClass()
        Dim derived As New MyDerivedClass()
        Dim o As Object = derived
        Dim b As MyBaseClass = derived
        
        Console.WriteLine("base.GetType returns {0}", base.GetType())
        Console.WriteLine("derived.GetType returns {0}", derived.GetType())
        Console.WriteLine("Dim o As Object = derived; o.GetType returns {0}", o.GetType())
        Console.WriteLine("Dim b As MyBaseClass = derived; b.Type returns {0}", b.GetType())
    End Sub 
End Class 
' The example displays the following output:
'    base.GetType returns MyBaseClass
'    derived.GetType returns MyDerivedClass
'    Dim o As Object = derived; o.GetType returns MyDerivedClass
'    Dim b As MyBaseClass = derived; b.Type returns MyDerivedClass

Remarks

因为System.Object在.NET Framework 类型系统中,是所有类型的基类GetType方法可用于返回Type表示所有.NET Framework 类型的对象。Because System.Object is the base class for all types in the .NET Framework type system, the GetType method can be used to return Type objects that represent all .NET Framework types. .NET Framework 能够识别以下五个类别的类型:The .NET Framework recognizes the following five categories of types:

两个对象xy具有相同的运行时类型Object.ReferenceEquals(x.GetType(),y.GetType())返回trueFor two objects x and y that have identical runtime types, Object.ReferenceEquals(x.GetType(),y.GetType()) returns true. 下面的示例使用GetType方法替换ReferenceEquals方法,以确定一个数值是否与其他两个数值相同的类型。The following example uses the GetType method with the ReferenceEquals method to determine whether one numeric value is the same type as two other numeric values.

using System;

public class Example
{
   public static void Main()
   {
      int n1 = 12;
      int n2 = 82;
      long n3 = 12;
      
      Console.WriteLine("n1 and n2 are the same type: {0}",
                        Object.ReferenceEquals(n1.GetType(), n2.GetType()));
      Console.WriteLine("n1 and n3 are the same type: {0}",
                        Object.ReferenceEquals(n1.GetType(), n3.GetType()));
   }
}
// The example displays the following output:
//       n1 and n2 are the same type: True
//       n1 and n3 are the same type: False      
Module Example
   Public Sub Main()
      Dim n1 As Integer = 12
      Dim n2 As Integer = 82
      Dim n3 As Long = 12
      
      Console.WriteLine("n1 and n2 are the same type: {0}",
                        Object.ReferenceEquals(n1.GetType(), n2.GetType()))
      Console.WriteLine("n1 and n3 are the same type: {0}",
                        Object.ReferenceEquals(n1.GetType(), n3.GetType()))
   End Sub
End Module
' The example displays the following output:
'       n1 and n2 are the same type: True
'       n1 and n3 are the same type: False      

备注

若要确定对象是否为特定类型,可以使用你的语言的类型比较关键字或构造。To determine whether an object is a specific type, you can use your language's type comparison keyword or construct. 例如,可以使用TypeOf…Is在 Visual Basic 中构造或isC# 中的关键字。For example, you can use the TypeOf…Is construct in Visual Basic or the is keyword in C#.

GetType方法由派生的所有类型的继承ObjectThe GetType method is inherited by all types that derive from Object. 这意味着,除了使用您自己的语言比较关键字,你可以使用GetType方法来确定特定对象的类型,如以下示例所示。This means that, in addition to using your own language's comparison keyword, you can use the GetType method to determine the type of a particular object, as the following example shows.

using System;

public class Example
{
   public static void Main()
   {
      object[] values = { (int) 12, (long) 10653, (byte) 12, (sbyte) -5,
                         16.3, "string" }; 
      foreach (var value in values) {
         Type t = value.GetType();
         if (t.Equals(typeof(byte)))
            Console.WriteLine("{0} is an unsigned byte.", value);
         else if (t.Equals(typeof(sbyte)))
            Console.WriteLine("{0} is a signed byte.", value);
         else if (t.Equals(typeof(int)))   
            Console.WriteLine("{0} is a 32-bit integer.", value);
         else if (t.Equals(typeof(long)))   
            Console.WriteLine("{0} is a 32-bit integer.", value);
         else if (t.Equals(typeof(double)))
            Console.WriteLine("{0} is a double-precision floating point.", 
                              value);
         else
            Console.WriteLine("'{0}' is another data type.", value);
      }
   }
}
// The example displays the following output:
//    12 is a 32-bit integer.
//    10653 is a 32-bit integer.
//    12 is an unsigned byte.
//    -5 is a signed byte.
//    16.3 is a double-precision floating point.
//    'string' is another data type.
Module Example
   Public Sub Main()
      Dim values() As Object = { 12, CLng(10653), CByte(12), 
                                 CSbyte(-5), 16.3, "string" } 
      For Each value In values
         Dim t AS Type = value.GetType()
         If t.Equals(GetType(Byte))
            Console.WriteLine("{0} is an unsigned byte.", value)
         ElseIf t.Equals(GetType(SByte))
            Console.WriteLine("{0} is a signed byte.", value)
         ElseIf t.Equals(GetType(Integer))   
            Console.WriteLine("{0} is a 32-bit integer.", value)
         ElseIf t.Equals(GetType(Long))   
            Console.WriteLine("{0} is a 32-bit integer.", value)
         ElseIf t.Equals(GetType(Double))
            Console.WriteLine("{0} is a double-precision floating point.", 
                              value)
         Else
            Console.WriteLine("'{0}' is another data type.", value)
         End If   
      Next      
   End Sub
End Module
' The example displays the following output:
'       12 is a 32-bit integer.
'       10653 is a 32-bit integer.
'       12 is an unsigned byte.
'       -5 is a signed byte.
'       16.3 is a double-precision floating point.
'       'string' is another data type.

Type对象会公开与当前的类关联的元数据ObjectThe Type object exposes the metadata associated with the class of the current Object.

Applies to

See Also