Marshal 类

定义

public ref class Marshal abstract sealed

public ref class Marshal sealed

public static class Marshal

public sealed class Marshal

type Marshal = class

Public Class Marshal

Public NotInheritable Class Marshal

继承

Object

Marshal

示例

以下示例演示如何使用 由 Marshal 类定义的各种方法。

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

public value struct Point
{
public:
    property int X;
    property int Y;
};
extern bool CloseHandle(IntPtr h);

int main()
{
    // Demonstrate the use of public static fields of the Marshal
    // class.
    Console::WriteLine(
        "SystemDefaultCharSize={0},SystemMaxDBCSCharSize={1}",
        Marshal::SystemDefaultCharSize,
        Marshal::SystemMaxDBCSCharSize);

    // Demonstrate the use of the SizeOf method of the Marshal
    // class.
    Console::WriteLine("Number of bytes needed by a Point object: {0}",
        Marshal::SizeOf(Point::typeid));
    Point point;
    Console::WriteLine("Number of bytes needed by a Point object: {0}",
        Marshal::SizeOf(point));

    // Demonstrate how to call GlobalAlloc and 
    // GlobalFree using the Marshal class.
    IntPtr hglobal = Marshal::AllocHGlobal(100);
    Marshal::FreeHGlobal(hglobal);

    // Demonstrate how to use the Marshal class to get the Win32
    // error code when a Win32 method fails.
    bool isCloseHandleSuccess = CloseHandle(IntPtr(-1));
    if (!isCloseHandleSuccess)
    {
        Console::WriteLine(
            "CloseHandle call failed with an error code of: {0}",
            Marshal::GetLastWin32Error());
    }
};

// This is a platform invoke prototype. SetLastError is true,
// which allows the GetLastWin32Error method of the Marshal class
// to work correctly.    
[DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
extern bool CloseHandle(IntPtr h);

// This code produces the following output.
// 
// SystemDefaultCharSize=2, SystemMaxDBCSCharSize=1
// Number of bytes needed by a Point object: 8
// Number of bytes needed by a Point object: 8
// CloseHandle call failed with an error code of: 6

using System;
using System.Text;
using System.Runtime.InteropServices;

public struct Point
{
    public Int32 x, y;
}

public sealed class App
{
    static void Main()
    {
        // Demonstrate the use of public static fields of the Marshal class.
        Console.WriteLine("SystemDefaultCharSize={0}, SystemMaxDBCSCharSize={1}",
            Marshal.SystemDefaultCharSize, Marshal.SystemMaxDBCSCharSize);

        // Demonstrate the use of the SizeOf method of the Marshal class.
        Console.WriteLine("Number of bytes needed by a Point object: {0}",
            Marshal.SizeOf(typeof(Point)));
        Point p = new Point();
        Console.WriteLine("Number of bytes needed by a Point object: {0}",
            Marshal.SizeOf(p));

        // Demonstrate how to call GlobalAlloc and
        // GlobalFree using the Marshal class.
        IntPtr hglobal = Marshal.AllocHGlobal(100);
        Marshal.FreeHGlobal(hglobal);

        // Demonstrate how to use the Marshal class to get the Win32 error
        // code when a Win32 method fails.
        Boolean f = CloseHandle(new IntPtr(-1));
        if (!f)
        {
            Console.WriteLine("CloseHandle call failed with an error code of: {0}",
                Marshal.GetLastWin32Error());
        }
    }

    // This is a platform invoke prototype. SetLastError is true, which allows
    // the GetLastWin32Error method of the Marshal class to work correctly.
    [DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
    static extern Boolean CloseHandle(IntPtr h);
}

// This code produces the following output.
//
// SystemDefaultCharSize=2, SystemMaxDBCSCharSize=1
// Number of bytes needed by a Point object: 8
// Number of bytes needed by a Point object: 8
// CloseHandle call failed with an error code of: 6

Imports System.Text
Imports System.Runtime.InteropServices
Imports System.Security.Permissions



Public Structure Point
    Public x, y As Int32
End Structure



Public NotInheritable Class App

    <SecurityPermission(SecurityAction.LinkDemand, Unrestricted:=True)> _
    Shared Sub Main()
        ' Demonstrate the use of public static fields of the Marshal class.
        Console.WriteLine("SystemDefaultCharSize={0}, SystemMaxDBCSCharSize={1}", Marshal.SystemDefaultCharSize, Marshal.SystemMaxDBCSCharSize)
        ' Demonstrate the use of the SizeOf method of the Marshal class.
        Console.WriteLine("Number of bytes needed by a Point object: {0}", Marshal.SizeOf(GetType(Point)))
        Dim p As New Point()
        Console.WriteLine("Number of bytes needed by a Point object: {0}", Marshal.SizeOf(p))
        ' Demonstrate how to call GlobalAlloc and 
        ' GlobalFree using the Marshal class.
        Dim hglobal As IntPtr = Marshal.AllocHGlobal(100)
        Marshal.FreeHGlobal(hglobal)
        ' Demonstrate how to use the Marshal class to get the Win32 error 
        ' code when a Win32 method fails.
        Dim f As [Boolean] = CloseHandle(New IntPtr(-1))
        If Not f Then
            Console.WriteLine("CloseHandle call failed with an error code of: {0}", Marshal.GetLastWin32Error())
        End If

    End Sub


    ' This is a platform invoke prototype. SetLastError is true, which allows 
    ' the GetLastWin32Error method of the Marshal class to work correctly.    
    <DllImport("Kernel32", ExactSpelling:=True, SetLastError:=True)> _
    Shared Function CloseHandle(ByVal h As IntPtr) As [Boolean]

    End Function
End Class


' This code produces the following output.
' 
' SystemDefaultCharSize=2, SystemMaxDBCSCharSize=1
' Number of bytes needed by a Point object: 8
' Number of bytes needed by a Point object: 8
' CloseHandle call failed with an error code of: 6

注解

在 static 类上 Marshal 定义的方法对于使用非托管代码至关重要。 此类中定义的大多数方法通常由想要在托管和非托管编程模型之间提供桥梁的开发人员使用。 例如， StringToHGlobalAnsi 方法将托管堆) 的指定字符串 (的 ANSI 字符复制到非托管堆中的缓冲区。 它还分配大小合适的目标堆。

公共语言运行时提供特定的封送处理功能。 有关封送处理行为的详细信息，请参阅 互操作封送处理。

Read类中的 Marshal 和 Write 方法支持对齐和未对齐的访问。

字段

方法

适用于