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

定义

获取一个值,该值指示当前 Type 是否表示可以用来构造其他泛型类型的泛型类型定义。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

属性值

如果此 true 对象表示泛型类型定义,则为 Type;否则为 falsetrue if the Type object represents a generic type definition; otherwise, false.

示例

下面的示例显示信息的类型,包括指示为泛型类型定义。The following example displays information about a type, including whether or not it is a generic type definition. 构造类型、 其泛型类型定义,和普通类型,则会显示信息。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
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

注解

泛型类型定义是可从其构造其他类型的模板。A generic type definition is a template from which other types can be constructed. 例如,从泛型类型定义G<T>(以表示C#语法;G(Of T)在 Visual Basic 中或generic <typename T> ref class G中C++) 可以构造并实例化类型G<int>(G(Of Integer)在 Visual Basic 中),通过调用MakeGenericType方法,其中包含泛型自变量列表Int32类型。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. 给定Type对象表示此构造类型,GetGenericTypeDefinition方法获取泛型类型定义回再次。Given a Type object representing this constructed type, the GetGenericTypeDefinition method gets the generic type definition back again.

使用IsGenericTypeDefinition属性来确定是否可以从当前的类型创建新的类型。Use the IsGenericTypeDefinition property to determine whether you can create new types from the current type. 如果IsGenericTypeDefinition属性返回true,可以调用MakeGenericType方法来创建新的泛型类型。If the IsGenericTypeDefinition property returns true, you can call the MakeGenericType method to create new generic types.

有关泛型反射中使用的术语的固定条件列表,请参阅 IsGenericType 属性注解。For a list of the invariant conditions for terms used in generic reflection, see the IsGenericType property remarks.

适用于

另请参阅