Gets a value indicating whether the current Type represents a generic type definition, from which other generic types can be constructed.
Assembly: mscorlib (in mscorlib.dll)
Public Overridable ReadOnly Property IsGenericTypeDefinition As Booleanpublic virtual bool IsGenericTypeDefinition { get; }public:
virtual property bool IsGenericTypeDefinition {
bool get ();
}abstract IsGenericTypeDefinition : bool
override IsGenericTypeDefinition : boolProperty Value
Type: Systemtrue if the Type object represents a generic type definition; otherwise, false.
A generic type definition is a template from which other types can be constructed. For example, from the generic type definition G<T> (expressed in C# syntax; G(Of T) in Visual Basic or generic <typename T> ref class G in C++) you can construct and instantiate the type G<int> (G(Of Integer) in Visual Basic), by calling the MakeGenericType method with a generic argument list containing the Int32 type. Given a Type object representing this constructed type, the GetGenericTypeDefinition method gets the generic type definition back again.
Use the IsGenericTypeDefinition property to determine whether you can create new types from the current type. If the IsGenericTypeDefinition property returns true, you can call the MakeGenericType method to create new generic types.
For a list of the invariant conditions for terms used in generic reflection, see the IsGenericType property remarks.
The following example displays information about a type, including whether or not it is a generic type definition. Information is displayed for a constructed type, for its generic type definition, and for an ordinary type.
Imports System
Imports System.Reflection
Imports System.Collections.Generic
Imports Microsoft.VisualBasic
Public Class Test
Private Shared Sub DisplayGenericTypeInfo(ByVal t As Type)
Console.WriteLine(vbCrLf & t.ToString())
Console.WriteLine(vbTab & "Is this a generic type definition? " _
& t.IsGenericTypeDefinition)
Console.WriteLine(vbTab & "Is it a generic type? " _
& t.IsGenericType)
If t.IsGenericType Then
' If this is a generic type, display the type arguments.
'
Dim typeArguments As Type() = t.GetGenericArguments()
Console.WriteLine(vbTab & "List type arguments (" _
& typeArguments.Length & "):")
For Each tParam As Type In typeArguments
' If this is a type parameter, display its position.
'
If tParam.IsGenericParameter Then
Console.WriteLine(vbTab & vbTab & tParam.ToString() _
& vbTab & "(unassigned - parameter position " _
& tParam.GenericParameterPosition & ")")
Else
Console.WriteLine(vbTab & vbTab & tParam.ToString())
End If
Next tParam
End If
End Sub
Public Shared Sub Main()
Console.WriteLine(vbCrLf & "--- Display information about a constructed type, its")
Console.WriteLine(" generic type definition, and an ordinary type.")
' Create a Dictionary of Test objects, using strings for the
' keys.
Dim d As New Dictionary(Of String, Test)()
DisplayGenericTypeInfo(d.GetType())
DisplayGenericTypeInfo(d.GetType().GetGenericTypeDefinition())
' Display information for an ordinary type.
DisplayGenericTypeInfo(GetType(String))
End Sub 'Main
End Class 'Test
' This example produces the following output:
'
'--- Display information about a constructed type, its
' generic type definition, and an ordinary type.
'
'System.Collections.Generic.Dictionary[System.String, Test]
' Is this a generic type definition? False
' Is it a generic type? True
' List type arguments (2):
' System.String
' Test
'
'System.Collections.Generic.Dictionary[TKey,TValue]
' Is this a generic type definition? True
' Is it a generic type? True
' List type arguments (2):
' TKey (unassigned - parameter position 0)
' TValue (unassigned - parameter position 1)
'
'System.String
' Is this a generic type definition? False
' Is it a generic type? False
using System;
using System.Reflection;
using System.Collections.Generic;
public class Test
{
private static void DisplayGenericTypeInfo(Type t)
{
Console.WriteLine("\r\n{0}", t);
Console.WriteLine("\tIs this a generic type definition? {0}",
t.IsGenericTypeDefinition);
Console.WriteLine("\tIs it a generic type? {0}",
t.IsGenericType);
if (t.IsGenericType)
{
// If this is a generic type, display the type arguments.
//
Type[] typeArguments = t.GetGenericArguments();
Console.WriteLine("\tList type arguments ({0}):",
typeArguments.Length);
foreach (Type tParam in typeArguments)
{
// If this is a type parameter, display its
// position.
//
if (tParam.IsGenericParameter)
{
Console.WriteLine("\t\t{0}\t(unassigned - parameter position {1})",
tParam,
tParam.GenericParameterPosition);
}
else
{
Console.WriteLine("\t\t{0}", tParam);
}
}
}
}
public static void Main()
{
Console.WriteLine("\r\n--- Display information about a constructed type, its");
Console.WriteLine(" generic type definition, and an ordinary type.");
// Create a Dictionary of Test objects, using strings for the
// keys.
Dictionary<string, Test> d = new Dictionary<string, Test>();
// Display information for the constructed type and its generic
// type definition.
DisplayGenericTypeInfo(d.GetType());
DisplayGenericTypeInfo(d.GetType().GetGenericTypeDefinition());
// Display information for an ordinary type.
DisplayGenericTypeInfo(typeof(string));
}
}
/* This example produces the following output:
--- Display information about a constructed type, its
generic type definition, and an ordinary type.
System.Collections.Generic.Dictionary[System.String,Test]
Is this a generic type definition? False
Is it a generic type? True
List type arguments (2):
System.String
Test
System.Collections.Generic.Dictionary[TKey,TValue]
Is this a generic type definition? True
Is it a generic type? True
List type arguments (2):
TKey (unassigned - parameter position 0)
TValue (unassigned - parameter position 1)
System.String
Is this a generic type definition? False
Is it a generic type? False
*/
using namespace System;
using namespace System::Reflection;
using namespace System::Collections::Generic;
public ref class Test
{
private:
static void DisplayGenericTypeInfo( Type^ t )
{
Console::WriteLine( L"\r\n{0}", t );
Console::WriteLine( L"\tIs this a generic type definition? {0}",
t->IsGenericTypeDefinition );
Console::WriteLine( L"\tIs it a generic type? {0}",
t->IsGenericType );
if ( t->IsGenericType )
{
// If this is a generic type, display the type arguments.
//
array<Type^>^typeArguments = t->GetGenericArguments();
Console::WriteLine( L"\tList type arguments ({0}):",
typeArguments->Length );
System::Collections::IEnumerator^ myEnum =
typeArguments->GetEnumerator();
while ( myEnum->MoveNext() )
{
Type^ tParam = safe_cast<Type^>(myEnum->Current);
// If this is a type parameter, display its
// position.
//
if ( tParam->IsGenericParameter )
{
Console::WriteLine(
L"\t\t{0}\t(unassigned - parameter position {1})",
tParam, tParam->GenericParameterPosition );
}
else
{
Console::WriteLine( L"\t\t{0}", tParam );
}
}
}
}
public:
static void Main()
{
Console::Write( L"\r\n--- Display information about a " );
Console::WriteLine( L"constructed type, its" );
Console::WriteLine( L" generic type definition, and an ordinary type." );
// Create a Dictionary of Test objects, using strings for the
// keys.
Dictionary< String^,Test^ >^ d = gcnew Dictionary< String^,Test^ >;
// Display information for the constructed type and its generic
// type definition.
DisplayGenericTypeInfo( d->GetType() );
DisplayGenericTypeInfo( d->GetType()->GetGenericTypeDefinition() );
// Display information for an ordinary type.
DisplayGenericTypeInfo( String::typeid );
}
};
int main()
{
Test::Main();
}
/* This example produces the following output:
--- Display information about a constructed type, its
generic type definition, and an ordinary type.
System.Collections.Generic.Dictionary[System.String,Test]
Is this a generic type definition? False
Is it a generic type? True
List type arguments (2):
System.String
Test
System.Collections.Generic.Dictionary[TKey,TValue]
Is this a generic type definition? True
Is it a generic type? True
List type arguments (2):
TKey (unassigned - parameter position 0)
TValue (unassigned - parameter position 1)
System.String
Is this a generic type definition? False
Is it a generic type? False
*/
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.