Marshal.ReadInt32 方法

参考

定义

命名空间:: System.Runtime.InteropServices

程序集:: System.Runtime.InteropServices.dll

程序集:: mscorlib.dll

程序集:: netstandard.dll

重要

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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

Source:: Marshal.cs

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);

[System.Security.SecurityCritical]
public static int ReadInt32 (IntPtr ptr);

public static int ReadInt32 (IntPtr ptr);

[<System.Security.SecurityCritical>]
static member ReadInt32 : nativeint -> int

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。

Int32

从非托管内存中读取的 32 位带符号整数。

属性: SecurityCriticalAttribute

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)

适用于

ReadInt32(IntPtr, Int32)

Source:: Marshal.cs

Source:: Marshal.cs

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);

[System.Security.SecurityCritical]
public static int ReadInt32 (IntPtr ptr, int ofs);

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

[<System.Security.SecurityCritical>]
static member ReadInt32 : nativeint * int -> int

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。

Int32

从非托管内存中读取的 32 位带符号整数。

属性: SecurityCriticalAttribute

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

适用于

ReadInt32(Object, Int32)

Source:: Marshal.CoreCLR.cs

Source:: Marshal.CoreCLR.cs

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.")]
[System.Security.SecurityCritical]
public static int ReadInt32 (object ptr, int ofs);

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

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

[System.Security.SecurityCritical]
public static int ReadInt32 (object ptr, int ofs);

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

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

static member ReadInt32 : obj * int -> int

[<System.Security.SecurityCritical>]
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。

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 SecurityCriticalAttribute

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)

适用于

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通过

ReadInt32(IntPtr)

参数

返回

例外

示例

注解

另请参阅

适用于

ReadInt32(IntPtr, Int32)

参数

返回

例外

示例

注解

另请参阅

适用于

ReadInt32(Object, Int32)

参数

返回

例外

注解

另请参阅

适用于