Type.MakeGenericType(Type[]) Methode

Definition

Namespace:

System

Assembly:

System.Runtime.dll

Quelle:

Type.cs

Ersetzt die Typparameter der aktuellen generischen Typdefinition durch die Elemente eines Arrays von Typen und gibt ein Type-Objekt zurück, das den resultierenden konstruierten Typ darstellt.

public:
 virtual Type ^ MakeGenericType(... cli::array <Type ^> ^ typeArguments);

public virtual Type MakeGenericType (params Type[] typeArguments);

abstract member MakeGenericType : Type[] -> Type
override this.MakeGenericType : Type[] -> Type

Public Overridable Function MakeGenericType (ParamArray typeArguments As Type()) As Type

Parameter

typeArguments

Type[]

Ein Array von Typen, die die Typparameter des aktuellen generischen Typs ersetzen sollen.

Gibt zurück

Type

Ein Type, der den konstruierten Typ darstellt, der durch Ersetzen der Typparameter des aktuellen generischen Typs durch die Elemente von typeArguments erstellt wurde.

Ausnahmen

InvalidOperationException

Der aktuelle Typ stellt keine generische Typdefinition dar. Das heißt, IsGenericTypeDefinition gibt false zurück.

ArgumentNullException

typeArguments ist null.

- oder -

Ein beliebiges Element von typeArguments ist null.

ArgumentException

Die Anzahl der Elemente im typeArguments entspricht nicht der Anzahl von Typparametern in der aktuellen generischen Typdefinition.

- oder -

Ein beliebiges Element von typeArguments erfüllt nicht die Einschränkungen, die für den entsprechenden Typparameter des aktuellen generischen Typs angegeben wurden.

- oder -

typeArguments enthält ein Element, das ein Zeigertyp (IsPointer gibt true zurück), vom Typ „by-ref“ (IsByRef gibt true zurück) oder Void ist.

NotSupportedException

Die aufgerufene Methode wird in der Basisklasse nicht unterstützt. Abgeleitete Klassen müssen eine Implementation angeben.

Beispiele

Im folgenden Beispiel wird die MakeGenericType -Methode verwendet, um einen konstruierten Typ aus der generischen Typdefinition für den Dictionary<TKey,TValue> Typ zu erstellen. Der konstruierte Typ stellt eine Dictionary<TKey,TValue> von Test -Objekten mit Zeichenfolgenschlüsseln dar.

using namespace System;
using namespace System::Reflection;
using namespace System::Collections::Generic;

namespace Example
{
    public ref class Test
    {
    public:
        static void CreateConstructedType(void)
        {      
            Console::WriteLine("\r\n--- Create a constructed type"
                " from the generic Dictionary`2 type.");
            
            // Create a type object representing 
            // the generic Dictionary`2 type.
            Type^ genericType = Type::GetType(
                "System.Collections.Generic.Dictionary`2");
            if (genericType != nullptr)
            {  
                DisplayTypeInfo(genericType);
            }
            else
            {
                Console::WriteLine("The type is not found");
                return;
            }
            
            // Create an array of types to substitute for the type
            // parameters of Dictionary`2. 
            // The key is of type string, and the type to be 
            // contained in the Dictionary`2 is Test.
            array<Type^>^ typeArgs = {String::typeid, Test::typeid};
            Type^ constructedType = 
                genericType->MakeGenericType(typeArgs);
            DisplayTypeInfo(constructedType);
            
            // Compare the type objects obtained above to type objects
            // obtained using typeof() and GetGenericTypeDefinition().
            Console::WriteLine("\r\n--- Compare types obtained by"
                " different methods:");

            Type^ definedType = Dictionary<String^, Test^>::typeid;
            Console::WriteLine("\tAre the constructed types "
                "equal? {0}", definedType == constructedType);
            Console::WriteLine("\tAre the generic types equal? {0}", 
                definedType->GetGenericTypeDefinition() == genericType);
        }

    private:
        static void DisplayTypeInfo(Type^ typeToDisplay)
        {   
            Console::WriteLine("\r\n{0}", typeToDisplay);
            Console::WriteLine("\tIs this a generic type definition? "
                "{0}", typeToDisplay->IsGenericTypeDefinition);
            Console::WriteLine("\tIs it a generic type? "
                "{0}", typeToDisplay->IsGenericType);
            
            array<Type^>^ typeArguments = 
                typeToDisplay->GetGenericArguments();
            Console::WriteLine("\tList type arguments ({0}):", 
                typeArguments->Length);
            
            for each (Type^ typeArgument in typeArguments)
            {   
                Console::WriteLine("\t\t{0}", typeArgument);
            }
        }
    };
}

int main(void)
{
    Example::Test::CreateConstructedType();
}

/* This example produces the following output:

--- Create a constructed type from the generic Dictionary`2 type.

System.Collections.Generic.Dictionary`2[KeyType,ValueType]
          Is this a generic type definition? True
          Is it a generic type? True
          List type arguments (2):
                     K
                     V

System.Collections.Generic.Dictionary`2[System.String, Test]
          Is this a generic type definition? False
          Is it a generic type? True
          List type arguments (2):
                     System.String
                     Test

--- Compare types obtained by different methods:
          Are the constructed types equal? True
          Are the generic types equal? True
 */

using System;
using System.Reflection;
using System.Collections.Generic;

public class Test
{
    public static void Main()
    {
        Console.WriteLine("\r\n--- Create a constructed type from the generic Dictionary type.");

        // Create a type object representing the generic Dictionary 
        // type, by omitting the type arguments (but keeping the 
        // comma that separates them, so the compiler can infer the
        // number of type parameters).      
        Type generic = typeof(Dictionary<,>);
        DisplayTypeInfo(generic);

        // Create an array of types to substitute for the type
        // parameters of Dictionary. The key is of type string, and
        // the type to be contained in the Dictionary is Test.
        Type[] typeArgs = { typeof(string), typeof(Test) };

        // Create a Type object representing the constructed generic
        // type.
        Type constructed = generic.MakeGenericType(typeArgs);
        DisplayTypeInfo(constructed);

        // Compare the type objects obtained above to type objects
        // obtained using typeof() and GetGenericTypeDefinition().
        Console.WriteLine("\r\n--- Compare types obtained by different methods:");

        Type t = typeof(Dictionary<String, Test>);
        Console.WriteLine("\tAre the constructed types equal? {0}", t == constructed);
        Console.WriteLine("\tAre the generic types equal? {0}", 
            t.GetGenericTypeDefinition() == generic);
    }

    private static void DisplayTypeInfo(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);

        Type[] typeArguments = t.GetGenericArguments();
        Console.WriteLine("\tList type arguments ({0}):", typeArguments.Length);
        foreach (Type tParam in typeArguments)
        {
            Console.WriteLine("\t\t{0}", tParam);
        }
    }
}

/* This example produces the following output:

--- Create a constructed type from the generic Dictionary type.

System.Collections.Generic.Dictionary`2[TKey,TValue]
        Is this a generic type definition? True
        Is it a generic type? True
        List type arguments (2):
                TKey
                TValue

System.Collections.Generic.Dictionary`2[System.String, Test]
        Is this a generic type definition? False
        Is it a generic type? True
        List type arguments (2):
                System.String
                Test

--- Compare types obtained by different methods:
        Are the constructed types equal? True
        Are the generic types equal? True
 */

open System
open System.Collections.Generic

type Test() = class end

let displayTypeInfo (t: Type) =
    printfn $"\r\n{t}"

    printfn $"\tIs this a generic type definition? {t.IsGenericTypeDefinition}" 

    printfn $"\tIs it a generic type? {t.IsGenericType}"

    let typeArguments = t.GetGenericArguments()
    printfn $"\tList type arguments ({typeArguments.Length}):"
    for tParam in typeArguments do
        printfn $"\t\t{tParam}"

printfn "\r\n--- Create a constructed type from the generic Dictionary type."

// Create a type object representing the generic Dictionary 
// type, by calling .GetGenericTypeDefinition().
let generic = typeof<Dictionary<_,_>>.GetGenericTypeDefinition()
displayTypeInfo generic

// Create an array of types to substitute for the type
// parameters of Dictionary. The key is of type string, and
// the type to be contained in the Dictionary is Test.
let typeArgs = [| typeof<string>; typeof<Test> |]

// Create a Type object representing the constructed generic type.
let constructed = generic.MakeGenericType typeArgs
displayTypeInfo constructed

(* This example produces the following output:

--- Create a constructed type from the generic Dictionary type.

System.Collections.Generic.Dictionary`2[TKey,TValue]
        Is this a generic type definition? True
        Is it a generic type? True
        List type arguments (2):
                TKey
                TValue

System.Collections.Generic.Dictionary`2[System.String, Test]
        Is this a generic type definition? False
        Is it a generic type? True
        List type arguments (2):
                System.String
                Test
 *)

Imports System.Reflection
Imports System.Collections.Generic

Public Class Test
    Public Shared Sub Main()
        Console.WriteLine(vbCrLf & "--- Create a constructed type from the generic Dictionary type.")

        ' Create a type object representing the generic Dictionary 
        ' type, by omitting the type arguments (but keeping the 
        ' comma that separates them, so the compiler can infer the
        ' number of type parameters).
        Dim generic As Type = GetType(Dictionary(Of ,))
        DisplayTypeInfo(generic)

        ' Create an array of types to substitute for the type
        ' parameters of Dictionary. The key is of type string, and
        ' the type to be contained in the Dictionary is Test.
        Dim typeArgs() As Type = { GetType(String), GetType(Test) }

        ' Create a Type object representing the constructed generic
        ' type.
        Dim constructed As Type = generic.MakeGenericType(typeArgs)
        DisplayTypeInfo(constructed)

        ' Compare the type objects obtained above to type objects
        ' obtained using GetType() and GetGenericTypeDefinition().
        Console.WriteLine(vbCrLf & "--- Compare types obtained by different methods:")

        Dim t As Type = GetType(Dictionary(Of String, Test))
        Console.WriteLine(vbTab & "Are the constructed types equal? " _
            & (t Is constructed))
        Console.WriteLine(vbTab & "Are the generic types equal? " _ 
            & (t.GetGenericTypeDefinition() Is generic))
    End Sub

    Private Shared Sub DisplayTypeInfo(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)

        Dim typeArguments() As Type = t.GetGenericArguments()
        Console.WriteLine(vbTab & "List type arguments ({0}):", _
            typeArguments.Length)
        For Each tParam As Type In typeArguments       
            Console.WriteLine(vbTab & vbTab & tParam.ToString())
        Next
    End Sub
End Class

' This example produces the following output:
'
'--- Create a constructed type from the generic Dictionary type.
'
'System.Collections.Generic.Dictionary'2[TKey,TValue]
'        Is this a generic type definition? True
'        Is it a generic type? True
'        List type arguments (2):
'                TKey
'                TValue
'
'System.Collections.Generic.Dictionary`2[System.String,Test]
'        Is this a generic type definition? False
'        Is it a generic type? True
'        List type arguments (2):
'                System.String
'                Test
'
'--- Compare types obtained by different methods:
'        Are the constructed types equal? True
'        Are the generic types equal? True

Hinweise

Weitere Informationen zu dieser API finden Sie unter Ergänzende API-Hinweise zu Type.MakeGenericType.

Weitere Informationen

• IsGenericTypeDefinition
• GetGenericTypeDefinition()
• Reflektion und generische Typen
• How to: Untersuchen und Instanziieren von generischen Typen mit Reflektion