Type.IsGenericTypeDefinition Egenskap
Definition
Viktigt
En del information gäller för förhandsversionen av en produkt och kan komma att ändras avsevärt innan produkten blir allmänt tillgänglig. Microsoft lämnar inga garantier, uttryckliga eller underförstådda, avseende informationen som visas här.
Hämtar ett värde som anger om den aktuella Type representerar en allmän typdefinition, från vilken andra generiska typer kan konstrueras.
public:
virtual property bool IsGenericTypeDefinition { bool get(); };public virtual bool IsGenericTypeDefinition { get; }member this.IsGenericTypeDefinition : boolPublic Overridable ReadOnly Property IsGenericTypeDefinition As BooleanEgenskapsvärde
trueom objektet Type representerar en allmän typdefinition, annars . false
Exempel
I följande exempel visas information om en typ, inklusive om det är en allmän typdefinition eller inte. Information visas för en konstruerad typ, för dess generiska typdefinition och för en vanlig typ.
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
*/
open System
open System.Collections.Generic
type Test() = class end
let displayGenericTypeInfo (t: Type) =
printfn $"\n{t}"
printfn $"\tIs this a generic type definition? {t.IsGenericTypeDefinition}"
printfn $"\tIs it a generic type? {t.IsGenericType}"
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
// If this is a type parameter, display its
// position.
if tParam.IsGenericParameter then
printfn $"\t\t{tParam}\t(unassigned - parameter position {tParam.GenericParameterPosition})"
else
printfn $"\t\t{tParam}"
printfn "\r\n--- Display information about a constructed type, its"
printfn " generic type definition, and an ordinary type."
// Create a Dictionary of Test objects, using strings for the keys.
let d = 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
Kommentarer
En allmän typdefinition är en mall som andra typer kan konstrueras från. Från den allmänna C#-typdefinitionen G<T> kan du till exempel skapa och instansiera typen G<int> (G(Of Integer) i Visual Basic) genom att anropa metoden MakeGenericType med en allmän argumentlista som innehåller typen Int32. Med tanke på ett Type objekt som representerar den här konstruerade typen hämtar metoden den generiska typdefinitionen GetGenericTypeDefinition igen.
Använd egenskapen IsGenericTypeDefinition för att avgöra om du kan skapa nya typer från den aktuella typen. Om egenskapen IsGenericTypeDefinition returnerar truekan du anropa MakeGenericType metoden för att skapa nya generiska typer.
En lista över de invarianta villkoren för termer som används i allmän reflektion finns i egenskapskommentarerna IsGenericType .