Type.ContainsGenericParameters Properti

Definisi

Ruang nama:

System

Rakitan:

netstandard.dll, System.Runtime.dll

Sumber:

Type.Helpers.cs

Mendapatkan nilai yang menunjukkan apakah objek saat ini Type memiliki parameter jenis yang belum digantikan oleh jenis tertentu.

public:
 virtual property bool ContainsGenericParameters { bool get(); };

public virtual bool ContainsGenericParameters { get; }

member this.ContainsGenericParameters : bool

Public Overridable ReadOnly Property ContainsGenericParameters As Boolean

Nilai Properti

Boolean

true Type jika objek itu sendiri adalah parameter jenis generik atau memiliki parameter jenis yang jenis tertentu belum disediakan; jika tidak, false.

Contoh

Contoh berikut mendefinisikan kelas generik dengan dua parameter jenis dan kemudian menentukan kelas generik kedua yang berasal dari kelas pertama. Kelas dasar kelas turunan memiliki dua argumen jenis: yang pertama adalah Int32 dan yang kedua adalah parameter jenis dari jenis turunan. Contoh menampilkan informasi tentang kelas generik ini, termasuk posisi yang dilaporkan oleh GenericParameterPosition properti .

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

// Define a base class with two type parameters.
public class Base<T, U> { }

// Define a derived class. The derived class inherits from a constructed
// class that meets the following criteria:
//   (1) Its generic type definition is Base<T, U>.
//   (2) It specifies int for the first type parameter.
//   (3) For the second type parameter, it uses the same type that is used
//       for the type parameter of the derived class.
// Thus, the derived class is a generic type with one type parameter, but
// its base class is an open constructed type with one type argument and
// one type parameter.
public class Derived<V> : Base<int, V> { }

public class Test
{
    public static void Main()
    {
        Console.WriteLine(
            "\r\n--- Display a generic type and the open constructed");
        Console.WriteLine("    type from which it is derived.");

        // Create a Type object representing the generic type definition 
        // for the Derived type, by omitting the type argument. (For
        // types with multiple type parameters, supply the commas but
        // omit the type arguments.) 
        //
        Type derivedType = typeof(Derived<>);
        DisplayGenericTypeInfo(derivedType);

        // Display its open constructed base type.
        DisplayGenericTypeInfo(derivedType.BaseType);
    }

    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);

        Console.WriteLine("\tDoes it have unassigned generic parameters? {0}", 
            t.ContainsGenericParameters);

        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)
            {
                // IsGenericParameter is true only for generic type
                // parameters.
                //
                if (tParam.IsGenericParameter)
                {
                    Console.WriteLine(
                        "\t\t{0}  (unassigned - parameter position {1})",
                        tParam,
                        tParam.GenericParameterPosition);
                }
                else
                {
                    Console.WriteLine("\t\t{0}", tParam);
                }
            }
        }
    }
}

/* This example produces the following output:

--- Display a generic type and the open constructed
    type from which it is derived.

Derived`1[V]
        Is this a generic type definition? True
        Is it a generic type? True
        Does it have unassigned generic parameters? True
        List type arguments (1):
                V  (unassigned - parameter position 0)

Base`2[System.Int32,V]
        Is this a generic type definition? False
        Is it a generic type? True
        Does it have unassigned generic parameters? True
        List type arguments (2):
                System.Int32
                V  (unassigned - parameter position 0)
 */

open System
open System.Reflection
open System.Collections.Generic

// Define a base class with two type parameters.
type Base<'T, 'U>() = class end

// Define a derived class. The derived class inherits from a constructed
// class that meets the following criteria:
//   (1) Its generic type definition is Base<T, U>.
//   (2) It specifies int for the first type parameter.
//   (3) For the second type parameter, it uses the same type that is used
//       for the type parameter of the derived class.
// Thus, the derived class is a generic type with one type parameter, but
// its base class is an open constructed type with one type argument and
// one type parameter.
type Derived<'V>() = inherit Base<int, 'V>()

let displayGenericTypeInfo (t: Type) =
    printfn $"\n{t}"
    printfn $"\tIs this a generic type definition? {t.IsGenericTypeDefinition}"
    printfn $"\tIs it a generic type? {t.IsGenericType}"
    printfn $"\tDoes it have unassigned generic parameters? {t.ContainsGenericParameters}"

    if t.IsGenericType then
        // If this is a generic type, display the type arguments.
        let typeArguments = t.GetGenericArguments()

        printfn $"\tList type arguments ({typeArguments.Length}):"

        for tParam in typeArguments do
            // IsGenericParameter is true only for generic type
            // parameters.
            if tParam.IsGenericParameter then
                printfn $"\t\t{tParam}  (unassigned - parameter position {tParam.GenericParameterPosition})"
            else
                printfn $"\t\t{tParam}"

printfn $"\r\n--- Display a generic type and the open constructed"
printfn $"    type from which it is derived."

// Create a Type object representing the generic type definition 
// for the Derived type, by omitting the type argument. (For
// types with multiple type parameters, supply the commas but
// omit the type arguments.) 
//
let derivedType = (typeof<Derived<_>>).GetGenericTypeDefinition()
displayGenericTypeInfo derivedType

// Display its open constructed base type.
displayGenericTypeInfo derivedType.BaseType

(* This example produces the following output:

--- Display a generic type and the open constructed
    type from which it is derived.

Derived`1[V]
        Is this a generic type definition? True
        Is it a generic type? True
        Does it have unassigned generic parameters? True
        List type arguments (1):
                V  (unassigned - parameter position 0)

Base`2[System.Int32,V]
        Is this a generic type definition? False
        Is it a generic type? True
        Does it have unassigned generic parameters? True
        List type arguments (2):
                System.Int32
                V  (unassigned - parameter position 0)
 *)

Imports System.Reflection
Imports System.Collections.Generic

' Define a base class with two type parameters.
Public Class Base(Of T, U)
End Class

' Define a derived class. The derived class inherits from a constructed
' class that meets the following criteria:
'   (1) Its generic type definition is Base<T, U>.
'   (2) It uses int for the first type parameter.
'   (3) For the second type parameter, it uses the same type that is used
'       for the type parameter of the derived class.
' Thus, the derived class is a generic type with one type parameter, but
' its base class is an open constructed type with one assigned type
' parameter and one unassigned type parameter.
Public Class Derived(Of V)
    Inherits Base(Of Integer, V)
End Class

Public Class Test
    
    Public Shared Sub Main() 
        Console.WriteLine(vbCrLf _
            & "--- Display a generic type and the open constructed")
        Console.WriteLine("    type from which it is derived.")
        
        ' Create a Type object representing the generic type definition 
        ' for the Derived type, by omitting the type argument. (For
        ' types with multiple type parameters, supply the commas but
        ' omit the type arguments.) 
        '
        Dim derivedType As Type = GetType(Derived(Of ))
        DisplayGenericTypeInfo(derivedType)
        
        ' Display its open constructed base type.
        DisplayGenericTypeInfo(derivedType.BaseType)
    
    End Sub
    
    Private Shared Sub DisplayGenericTypeInfo(ByVal t As Type) 
        Console.WriteLine(vbCrLf & "{0}", t)
        
        Console.WriteLine(vbTab & "Is this a generic type definition? " _
            & t.IsGenericTypeDefinition)
        
        Console.WriteLine(vbTab & "Is it a generic type? " _
            & t.IsGenericType)
        
        Console.WriteLine(vbTab _
            & "Does it have unassigned generic parameters? " _
            & t.ContainsGenericParameters)
        
        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
                ' IsGenericParameter is true only for generic type
                ' parameters.
                '
                If tParam.IsGenericParameter Then
                    Console.WriteLine(vbTab & vbTab & tParam.ToString() _
                        & "  (unassigned - parameter position " _
                        & tParam.GenericParameterPosition & ")")
                Else
                    Console.WriteLine(vbTab & vbTab & tParam.ToString())
                End If
            Next tParam
        End If
    
    End Sub
End Class

' This example produces the following output:
'
'--- Display a generic type and the open constructed
'    type from which it is derived.
'
'Derived`1[V]
'        Is this a generic type definition? True
'        Is it a generic type? True
'        Does it have unassigned generic parameters? True
'        List type arguments (1):
'                V  (unassigned - parameter position 0)
'
'Base`2[System.Int32,V]
'        Is this a generic type definition? False
'        Is it a generic type? True
'        Does it have unassigned generic parameters? True
'        List type parameters (2):
'                System.Int32
'                V  (unassigned - parameter position 0)
'

Keterangan

Untuk membuat instans jenis, tidak boleh ada definisi jenis generik atau jenis konstruksi terbuka dalam argumen jenis itu sendiri, dalam jenis generik yang mencakup, atau dalam elemen jenis apa pun. Cara lain untuk mengatakan ini adalah bahwa ketika diperiksa secara rekursif, jenisnya tidak boleh berisi parameter jenis generik.

Karena jenisnya bisa sangat kompleks, membuat penentuan ini sulit. Untuk kenyamanan dan untuk mengurangi kemungkinan kesalahan, ContainsGenericParameters properti menyediakan cara standar untuk membedakan antara jenis konstruksi tertutup, yang dapat diinstruksikan, dan jenis konstruksi terbuka, yang tidak dapat. ContainsGenericParameters Jika properti mengembalikan true, jenis tidak dapat dibuat.

Properti ContainsGenericParameters mencari secara rekursif untuk parameter jenis. Misalnya, ia mengembalikan true array yang elemennya adalah jenis A<T> (A(Of T) di Visual Basic), meskipun array tidak sendiri generik. Kontras false ini dengan perilaku IsGenericType properti, yang mengembalikan untuk array.

Untuk sekumpulan contoh kelas dan tabel yang memperlihatkan nilai ContainsGenericParameters properti, lihat IsGenericType.

Lihat juga

• ContainsGenericParameters
• IsGenericTypeDefinition
• MakeGenericType(Type[])
• Refleksi dan Jenis Generik
• Cara: Memeriksa dan Membuat Instans Jenis Generik dengan Pantulan