Object.GetType Method (System) (original) (raw)

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Object.GetType Method

• Reference

Definition

Gets the Type of the current instance.

public:
 Type ^ GetType();

public Type GetType ();

member this.GetType : unit -> Type

Public Function GetType () As Type

Returns

The exact runtime type of the current instance.

Examples

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

type MyBaseClass() = class end

type MyDerivedClass() = 
    inherit MyBaseClass()

let myBase = MyBaseClass()
let myDerived = MyDerivedClass()
let o: obj = myDerived
let b: MyBaseClass = myDerived

printfn $"mybase: Type is {myBase.GetType()}"
printfn $"myDerived: Type is {myDerived.GetType()}"
printfn $"object o = myDerived: Type is {o.GetType()}"
printfn $"MyBaseClass b = myDerived: Type is {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

Because System.Object is the base class for all types in the .NET type system, the GetType method can be used to return Type objects that represent all .NET types. .NET recognizes the following five categories of types:

• Classes, which are derived from System.Object,
• Value types, which are derived from System.ValueType.
• Interfaces, which are derived from System.Object starting with the .NET Framework 2.0.
• Enumerations, which are derived from System.Enum.
• Delegates, which are derived from System.MulticastDelegate.

For two objects x and y that have identical runtime types, Object.ReferenceEquals(x.GetType(),y.GetType()) returns true. 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.

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

open System

let n1 = 12
let n2 = 82
let n3 = 12L

printfn $"n1 and n2 are the same type: {Object.ReferenceEquals(n1.GetType(), n2.GetType())}"
printfn $"n1 and n3 are the same type: {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

Note

To determine whether an object is a specific type, you can use your language's type comparison keyword or construct. For example, you can use the TypeOf…Is construct in Visual Basic or the is keyword in C#.

The GetType method is inherited by all types that derive from Object. 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.

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 64-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 64-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.

let values: obj[] = 
    [| 12; 10653L; 12uy
       -5y; 16.3; "string" |]

for value in values do
    let t = value.GetType()
    if t.Equals typeof<byte> then
        printfn $"{value} is an unsigned byte."
    elif t.Equals typeof<sbyte> then
        printfn $"{value} is a signed byte."
    elif t.Equals typeof<int> then
        printfn $"{value} is a 32-bit integer."
    elif t.Equals typeof<int64> then
        printfn $"{value} is a 64-bit integer."
    elif t.Equals typeof<double> then
        printfn $"{value} is a double-precision floating point."
    else
        printfn $"'{value}' is another data type."

// 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 64-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.

The Type object exposes the metadata associated with the class of the current Object.

Applies to

See also

• Type

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