Type.IsGenericTypeDefinition Type.IsGenericTypeDefinition Type.IsGenericTypeDefinition Type.IsGenericTypeDefinition Property

Definizione

Ottiene un valore che indica se la classe Type corrente rappresenta una definizione di tipo generico, da cui è possibile costruire altri tipi generici.Gets a value indicating whether the current Type represents a generic type definition, from which other generic types can be constructed.

public:
 virtual property bool IsGenericTypeDefinition { bool get(); };
public virtual bool IsGenericTypeDefinition { get; }
member this.IsGenericTypeDefinition : bool
Public Overridable ReadOnly Property IsGenericTypeDefinition As Boolean

Valore della proprietà

true se l'oggetto Type rappresenta una definizione di tipo generico; in caso contrario, false.true if the Type object represents a generic type definition; otherwise, false.

Esempi

Nell'esempio seguente vengono visualizzate informazioni su un tipo, ad esempio se si tratta di una definizione di tipo generico.The following example displays information about a type, including whether or not it is a generic type definition. Vengono visualizzate informazioni per un tipo costruito, per la definizione di tipo generico e per un tipo ordinario.Information is displayed for a constructed type, for its generic type definition, and for an ordinary type.

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
 */
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
 */
Imports System.Reflection
Imports System.Collections.Generic

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
End Class

' 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

Commenti

Una definizione di tipo generico è un modello da cui è possibile costruire altri tipi.A generic type definition is a template from which other types can be constructed. Ad esempio, dalla definizione G<T> di tipo generico (espressa nella C# sintassi; G(Of Integer) MakeGenericType G<int> in Visual Basic o generic <typename T> ref class G in C++) è possibile creare e creare un'istanza del tipo (in Visual Basic), chiamando il metodo con un elenco di argomenti generici contenente G(Of T) Int32Digitare.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. Dato un Type oggetto che rappresenta questo tipo costruito, GetGenericTypeDefinition il metodo ottiene nuovamente la definizione di tipo generico.Given a Type object representing this constructed type, the GetGenericTypeDefinition method gets the generic type definition back again.

Utilizzare la IsGenericTypeDefinition proprietà per determinare se è possibile creare nuovi tipi dal tipo corrente.Use the IsGenericTypeDefinition property to determine whether you can create new types from the current type. Se la IsGenericTypeDefinition proprietà restituisce true, è possibile chiamare il MakeGenericType metodo per creare nuovi tipi generici.If the IsGenericTypeDefinition property returns true, you can call the MakeGenericType method to create new generic types.

Per un elenco delle condizioni invariabili relative ai termini usati dal processo di reflection generico, vedere i commenti sulla proprietà IsGenericType.For a list of the invariant conditions for terms used in generic reflection, see the IsGenericType property remarks.

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