通过

Type.HasElementType 属性

  • 参考

定义

命名空间:
System
程序集:
mscorlib.dll, System.Runtime.dll
程序集:
netstandard.dll, System.Runtime.dll
程序集:
System.Runtime.dll
程序集:
mscorlib.dll
程序集:
netstandard.dll
Source:
Type.cs
Source:
Type.cs
Source:
Type.cs
Source:
Type.cs

获取一个值，通过该值指示当前 Type 是包含还是引用另一类型，即当前 Type 是数组、指针还是通过引用传递。

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

属性值

Boolean

如果 true 为数组、指针或按引用传递，则为 Type；否则为 false。

实现

HasElementType

示例

以下示例根据对象是数组、引用类型还是指针返回 true 或 false 。

using namespace System;
using namespace System::Reflection;
using namespace System::Runtime::InteropServices;

public ref class Example
{
public:
    // This method is for demonstration purposes. It includes a
    // tracking reference (C# ref, VB ByRef), an out parameter,
    // and a pointer.
    void Test(int% x, [OutAttribute()] int% y, int* z)
    { 
        *z = x = y = 0; 
    }    
};

int main()
{
    // All of the following display 'True'.

    // Define a managed array, get its type, and display HasElementType. 
    array<Example^>^ examples = {gcnew Example(), gcnew Example()};
    Type^ t = examples::typeid; 
    Console::WriteLine(t);
    Console::WriteLine("HasElementType is '{0}' for managed array types.", t->HasElementType);

    // When you use Reflection Emit to emit dynamic methods and
    // assemblies, you can create array types using MakeArrayType.
    // The following creates the type 'array of Example'.
    t = Example::typeid->MakeArrayType();
    Console::WriteLine("HasElementType is '{0}' for managed array types.", t->HasElementType);

    // When you reflect over methods, HasElementType is true for
    // ref, out, and pointer parameter types. The following 
    // gets the Test method, defined above, and examines its
    // parameters.
    MethodInfo^ mi = Example::typeid->GetMethod("Test");
    array<ParameterInfo^>^ parms = mi->GetParameters();
    t = parms[0]->ParameterType;
    Console::WriteLine("HasElementType is '{0}' for ref parameter types.", t->HasElementType);
    t = parms[1]->ParameterType;
    Console::WriteLine("HasElementType is '{0}' for out parameter types.", t->HasElementType);
    t = parms[2]->ParameterType;
    Console::WriteLine("HasElementType is '{0}' for pointer parameter types.", t->HasElementType);

    // When you use Reflection Emit to emit dynamic methods and
    // assemblies, you can create pointer and ByRef types to use
    // when you define method parameters.
    t = Example::typeid->MakePointerType();
    Console::WriteLine("HasElementType is '{0}' for pointer types.", t->HasElementType);
    t = Example::typeid->MakeByRefType();
    Console::WriteLine("HasElementType is '{0}' for ByRef types.", t->HasElementType);
}

// This code must be compiled with the /unsafe switch:
//   csc /unsafe source.cs
using System;
using System.Reflection;

public class Example
{
    // This method is for demonstration purposes.
    unsafe public void Test(ref int x, out int y, int* z)
    {
        *z = x = y = 0;
    }

    public static void Main()
    {
        // All of the following display 'True'.

        // Define an array, get its type, and display HasElementType.
        int[] nums = {1, 1, 2, 3, 5, 8, 13};
        Type t = nums.GetType();
        Console.WriteLine("HasElementType is '{0}' for array types.", t.HasElementType);

        // Test an array type without defining an array.
        t = typeof(Example[]);
        Console.WriteLine("HasElementType is '{0}' for array types.", t.HasElementType);

        // When you use Reflection Emit to emit dynamic methods and
        // assemblies, you can create array types using MakeArrayType.
        // The following creates the type 'array of Example'.
        t = typeof(Example).MakeArrayType();
        Console.WriteLine("HasElementType is '{0}' for array types.", t.HasElementType);

        // When you reflect over methods, HasElementType is true for
        // ref, out, and pointer parameter types. The following
        // gets the Test method, defined above, and examines its
        // parameters.
        MethodInfo mi = typeof(Example).GetMethod("Test");
        ParameterInfo[] parms = mi.GetParameters();
        t = parms[0].ParameterType;
        Console.WriteLine("HasElementType is '{0}' for ref parameter types.", t.HasElementType);
        t = parms[1].ParameterType;
        Console.WriteLine("HasElementType is '{0}' for out parameter types.", t.HasElementType);
        t = parms[2].ParameterType;
        Console.WriteLine("HasElementType is '{0}' for pointer parameter types.", t.HasElementType);

        // When you use Reflection Emit to emit dynamic methods and
        // assemblies, you can create pointer and ByRef types to use
        // when you define method parameters.
        t = typeof(Example).MakePointerType();
        Console.WriteLine("HasElementType is '{0}' for pointer types.", t.HasElementType);
        t = typeof(Example).MakeByRefType();
        Console.WriteLine("HasElementType is '{0}' for ByRef types.", t.HasElementType);
    }
}

#nowarn "9"
open FSharp.NativeInterop

type Example() =
    // This method is for demonstration purposes.
    member _.Test(x: int byref, y: int outref, z: int nativeptr) =
        x <- 0
        y <- 0
        NativePtr.write z 0

// All of the following display 'True'.

do
    // Define an array, get its type, and display HasElementType.
    let nums = [| 1; 1; 2; 3; 5; 8; 13 |]
    let t = nums.GetType()
    printfn $"HasElementType is '{t.HasElementType}' for array types."

    // Test an array type without defining an array.
    let t = typeof<Example[]>
    printfn $"HasElementType is '{t.HasElementType}' for array types."

    // When you use Reflection Emit to emit dynamic methods and
    // assemblies, you can create array types using MakeArrayType.
    // The following creates the type 'array of Example'.
    let t = typeof<Example>.MakeArrayType()
    printfn $"HasElementType is '{t.HasElementType}' for array types."

    // When you reflect over methods, HasElementType is true for
    // byref, outref, and pointer parameter types. The following
    // gets the Test method, defined above, and examines its
    // parameters.
    let mi = typeof<Example>.GetMethod "Test"
    let parms = mi.GetParameters()
    let t = parms[0].ParameterType
    printfn $"HasElementType is '{t.HasElementType}' for ref parameter types."
    let t = parms[1].ParameterType
    printfn $"HasElementType is '{t.HasElementType}' for out parameter types."
    let t = parms[2].ParameterType
    printfn $"HasElementType is '{t.HasElementType}' for pointer parameter types."

    // When you use Reflection Emit to emit dynamic methods and
    // assemblies, you can create pointer and ByRef types to use
    // when you define method parameters.
    let t = typeof<Example>.MakePointerType()
    printfn $"HasElementType is '{t.HasElementType}' for pointer types."
    let t = typeof<Example>.MakeByRefType()
    printfn $"HasElementType is '{t.HasElementType}' for ByRef types."

Imports System.Reflection
Imports System.Runtime.InteropServices

Public Class Example

    ' This method is for demonstration purposes.
    Public Shared Sub Test(ByRef x As Integer, <Out> ByRef y As Integer)
    End Sub

    Public Shared Sub Main()
        ' All of the following display 'True'.

        ' Define an array, get its type, and display HasElementType. 
        Dim nums() As Integer = {1, 1, 2, 3, 5, 8, 13}
        Dim t As Type = nums.GetType()
        Console.WriteLine("HasElementType is '{0}' for array types.", t.HasElementType)

        ' Test an array type without defining an array.
        t = GetType(Example())
        Console.WriteLine("HasElementType is '{0}' for array types.", t.HasElementType)

        ' When you use Reflection Emit to emit dynamic methods and
        ' assemblies, you can create array types using MakeArrayType.
        ' The following creates the type 'array of Example'.
        t = GetType(Example).MakeArrayType()
        Console.WriteLine("HasElementType is '{0}' for array types.", t.HasElementType)

        ' When you reflect over methods, HasElementType is true for
        ' ref, out, and pointer parameter types. The following 
        ' gets the Test method, defined above, and examines its
        ' parameters.
        Dim mi As MethodInfo = GetType(Example).GetMethod("Test")
        Dim parms() As ParameterInfo = mi.GetParameters()
        t = parms(0).ParameterType
        Console.WriteLine("HasElementType is '{0}' for ref parameter types.", t.HasElementType)
        t = parms(1).ParameterType
        Console.WriteLine("HasElementType is '{0}' for <Out> parameter types.", t.HasElementType)

        ' When you use Reflection Emit to emit dynamic methods and
        ' assemblies, you can create pointer and ByRef types to use
        ' when you define method parameters.
        t = GetType(Example).MakePointerType()
        Console.WriteLine("HasElementType is '{0}' for pointer types.", t.HasElementType)
        t = GetType(Example).MakeByRefType()
        Console.WriteLine("HasElementType is '{0}' for ByRef types.", t.HasElementType)
    End Sub 

End Class

注解

例如，Type.GetType (“Int32[]”) 。HasElementType 返回 true，但 Type.GetType (“Int32”) 。HasElementType 返回 false。 HasElementType 还返回 true “Int32*”和“Int32&”。

如果当前 Type 表示泛型类型或泛型类型或泛型方法的定义中的类型参数，则此属性始终返回 false。

适用于

另请参阅