Marshal.ReadInt32 方法

定义

命名空间:

System.Runtime.InteropServices

程序集:

System.Runtime.InteropServices.dll

从非托管内存中读取一个 32 位带符号整数。 支持从未对齐的内存位置进行读取。

重载

ReadInt32(IntPtr)	从非托管内存中读取一个 32 位带符号整数。
ReadInt32(IntPtr, Int32)	从非托管内存按给定的偏移量读取一个 32 位带符号整数。
ReadInt32(Object, Int32)	已过时. 从非托管内存按给定的偏移量读取一个 32 位带符号整数。

ReadInt32(IntPtr)

Source:

Marshal.cs

从非托管内存中读取一个 32 位带符号整数。

public:
 static int ReadInt32(IntPtr ptr);

public static int ReadInt32 (IntPtr ptr);

static member ReadInt32 : nativeint -> int

Public Shared Function ReadInt32 (ptr As IntPtr) As Integer

参数

ptr

IntPtr

nativeint

非托管内存中开始读取的地址。

返回

Int32

从非托管内存中读取的 32 位带符号整数。

例外

AccessViolationException

ptr 不是识别的格式。

- 或 -

ptr 为 null。

- 或 -

ptr 无效。

示例

以下示例演示如何使用 ReadInt32 和 WriteInt32 方法读取和写入非托管数组。

static void ReadWriteInt32()
{
    // Allocate unmanaged memory. 
    int elementSize = 4;
    IntPtr unmanagedArray = Marshal.AllocHGlobal(10 * elementSize);

    // Set the 10 elements of the C-style unmanagedArray
    for (int i = 0; i < 10; i++)
    {
        Marshal.WriteInt32(unmanagedArray, i * elementSize, ((Int32)(i + 1)));
    }
    Console.WriteLine("Unmanaged memory written.");

    Console.WriteLine("Reading unmanaged memory:");
    // Print the 10 elements of the C-style unmanagedArray
    for (int i = 0; i < 10; i++)
    {
        Console.WriteLine(Marshal.ReadInt32(unmanagedArray, i * elementSize));
    }

    Marshal.FreeHGlobal(unmanagedArray);

    Console.WriteLine("Done. Press Enter to continue.");
    Console.ReadLine();
}

Sub ReadWriteInt32()
    ' Allocate unmanaged memory. 
    Dim elementSize As Integer = 4
    Dim unmanagedArray As IntPtr = Marshal.AllocHGlobal(10 * elementSize)

    ' Set the 10 elements of the C-style unmanagedArray
    For i As Integer = 0 To 9
        Marshal.WriteInt32(unmanagedArray, i * elementSize, CType(i + 1, Int32))
    Next i
    Console.WriteLine("Unmanaged memory written.")

    Console.WriteLine("Reading unmanaged memory:")
    ' Print the 10 elements of the C-style unmanagedArray
    For i As Integer = 0 To 9
        Console.WriteLine(Marshal.ReadInt32(unmanagedArray, i * elementSize))
    Next i

    Marshal.FreeHGlobal(unmanagedArray)

    Console.WriteLine("Done. Press Enter to continue.")
    Console.ReadLine()
End Sub

下面的示例演示如何使用 ReadInt32 方法读取非托管 int 变量的值。

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



void main()
{
    // Create an unmanaged integer.
    int myVal = 42;

    // Read the int as a managed Int32.
        Int32 ^ myManagedVal = Marshal::ReadInt32((IntPtr) &myVal);

    // Display the value to the console.
    Console::WriteLine(myManagedVal);
}

注解

ReadInt32 具有 0 的隐式偏移量。 此方法允许与非托管 C 样式 Int32 数组直接交互，从而消除了在读取其元素值之前使用 Marshal.Copy) 复制到单独托管数组 (整个非托管数组的开销。

支持从未对齐的内存位置进行读取。

另请参阅

• Copy(Int32[], Int32, IntPtr, Int32)

ReadInt32(IntPtr, Int32)

Source:

Marshal.cs

从非托管内存按给定的偏移量读取一个 32 位带符号整数。

public:
 static int ReadInt32(IntPtr ptr, int ofs);

public static int ReadInt32 (IntPtr ptr, int ofs);

static member ReadInt32 : nativeint * int -> int

Public Shared Function ReadInt32 (ptr As IntPtr, ofs As Integer) As Integer

参数

ptr

IntPtr

nativeint

非托管内存中开始读取的基址。

ofs

Int32

额外的字节偏移量，在读取前添加到 ptr 参数中。

返回

Int32

从非托管内存中读取的 32 位带符号整数。

例外

AccessViolationException

基址 (ptr) 加上偏移字节 (ofs) 可产生空或无效地址。

示例

以下示例演示如何使用 ReadInt32 和 WriteInt32 方法读取和写入非托管数组。

static void ReadWriteInt32()
{
    // Allocate unmanaged memory. 
    int elementSize = 4;
    IntPtr unmanagedArray = Marshal.AllocHGlobal(10 * elementSize);

    // Set the 10 elements of the C-style unmanagedArray
    for (int i = 0; i < 10; i++)
    {
        Marshal.WriteInt32(unmanagedArray, i * elementSize, ((Int32)(i + 1)));
    }
    Console.WriteLine("Unmanaged memory written.");

    Console.WriteLine("Reading unmanaged memory:");
    // Print the 10 elements of the C-style unmanagedArray
    for (int i = 0; i < 10; i++)
    {
        Console.WriteLine(Marshal.ReadInt32(unmanagedArray, i * elementSize));
    }

    Marshal.FreeHGlobal(unmanagedArray);

    Console.WriteLine("Done. Press Enter to continue.");
    Console.ReadLine();
}

Sub ReadWriteInt32()
    ' Allocate unmanaged memory. 
    Dim elementSize As Integer = 4
    Dim unmanagedArray As IntPtr = Marshal.AllocHGlobal(10 * elementSize)

    ' Set the 10 elements of the C-style unmanagedArray
    For i As Integer = 0 To 9
        Marshal.WriteInt32(unmanagedArray, i * elementSize, CType(i + 1, Int32))
    Next i
    Console.WriteLine("Unmanaged memory written.")

    Console.WriteLine("Reading unmanaged memory:")
    ' Print the 10 elements of the C-style unmanagedArray
    For i As Integer = 0 To 9
        Console.WriteLine(Marshal.ReadInt32(unmanagedArray, i * elementSize))
    Next i

    Marshal.FreeHGlobal(unmanagedArray)

    Console.WriteLine("Done. Press Enter to continue.")
    Console.ReadLine()
End Sub

下面的示例演示如何使用 ReadInt32 方法读取非托管 int 变量的值。

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



void main()
{
    // Create an unmanaged int pointer.
    int * myVal;
    int tmp = 42;
    // Initialize it to another value.
    myVal = &tmp;

    // Read value as a managed Int32.
    Int32 ^ myManagedVal = Marshal::ReadInt32((IntPtr) myVal, 0);

    // Display the value to the console.
    Console::WriteLine(myManagedVal);
}

注解

ReadInt32 支持与非托管 32 位带符号数组的直接交互，从而消除了在读取其元素值之前使用 Marshal.Copy) 复制到单独托管数组 (整个非托管数组的开销。

支持从未对齐的内存位置进行读取。

另请参阅

• Copy(Int32[], Int32, IntPtr, Int32)
• ReadByte(Object, Int32)

ReadInt32(Object, Int32)

Source:

Marshal.CoreCLR.cs

注意

ReadInt32(Object, Int32) may be unavailable in future releases.

从非托管内存按给定的偏移量读取一个 32 位带符号整数。

public:
 static int ReadInt32(System::Object ^ ptr, int ofs);

[System.Obsolete("ReadInt32(Object, Int32) may be unavailable in future releases.")]
public static int ReadInt32 (object ptr, int ofs);

[<System.Obsolete("ReadInt32(Object, Int32) may be unavailable in future releases.")>]
static member ReadInt32 : obj * int -> int

Public Shared Function ReadInt32 (ptr As Object, ofs As Integer) As Integer

参数

ptr

Object

非托管内存中源对象的基址。

ofs

Int32

额外的字节偏移量，在读取前添加到 ptr 参数中。

返回

Int32

从非托管内存按给定的偏移量读取的 32 位带符号整数。

属性

ObsoleteAttribute

例外

AccessViolationException

基址 (ptr) 加上偏移字节 (ofs) 可产生空或无效地址。

ArgumentException

ptr 是 ArrayWithOffset 对象。 此方法不接受 ArrayWithOffset 参数。

注解

ReadInt32 支持与非托管 32 位带符号数组的直接交互，从而消除了在读取其元素值之前使用 Marshal.Copy) 复制到单独托管数组 (整个非托管数组的开销。

支持从未对齐的内存位置进行读取。

另请参阅

• Copy(Int32[], Int32, IntPtr, Int32)