Marshal.ReadInt32 方法

定義

命名空間:

System.Runtime.InteropServices

組件:

System.Runtime.InteropServices.dll

從 Unmanaged 記憶體讀取 32 位元帶正負號的整數。 支援讀取未配置的記憶體位置。

多載

ReadInt32(IntPtr)	從 Unmanaged 記憶體讀取 32 位元帶正負號的整數。
ReadInt32(IntPtr, Int32)	從 Unmanaged 記憶體中指定位移處讀取 32 位元帶正負號的整數。
ReadInt32(Object, Int32)	已淘汰. 從 Unmanaged 記憶體中指定位移處讀取 32 位元帶正負號的整數。

ReadInt32(IntPtr)

來源:

Marshal.cs

從 Unmanaged 記憶體讀取 32 位元帶正負號的整數。

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

參數

ptr

IntPtr

nativeint

從 Unmanaged 記憶體中讀取的位址。

傳回

Int32

從 Unmanaged 記憶體讀取的 32 位元帶正負號的整數。

例外狀況

AccessViolationException

ptr 不是可辨認的格式。

-或-

ptr 為 null。

-或-

ptr 無效。

範例

下列範例示範如何使用 和 WriteInt32 方法來讀取和寫入 Unmanaged 陣列ReadInt32。

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

下列範例示範如何使用 ReadInt32 方法來讀取 Unmanaged int 變數的值。

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);
}

備註

ReadInt32 具有 0 的隱含位移。 這個方法可讓您直接與 Unmanaged C 樣式 Int32 數位互動，避免在讀取其元素值之前，先將 Marshal.Copy 整個 Unmanaged 陣組複製 () (。

支援讀取未配置的記憶體位置。

另請參閱

• Copy(Int32[], Int32, IntPtr, Int32)

ReadInt32(IntPtr, Int32)

來源:

Marshal.cs

從 Unmanaged 記憶體中指定位移處讀取 32 位元帶正負號的整數。

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

參數

ptr

IntPtr

nativeint

從 Unmanaged 記憶體中讀取的基底位址 (Base Address)。

ofs

Int32

額外的位元組位移，會先加入至參數 ptr，然後再進行讀取。

傳回

Int32

從 Unmanaged 記憶體讀取的 32 位元帶正負號的整數。

例外狀況

AccessViolationException

基底位址 (ptr) 加上位移位元組 (ofs) 會產生 Null 或無效的位址。

範例

下列範例示範如何使用 和 WriteInt32 方法來讀取和寫入 Unmanaged 陣列ReadInt32。

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

下列範例示範如何使用 ReadInt32 方法來讀取 Unmanaged int 變數的值。

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);
}

備註

ReadInt32 可讓您直接與 Unmanaged 32 位帶正負號的陣列互動，避免在讀取其元素值之前，先將 Marshal.Copy 整個 Unmanaged 數位複製 () (。

支援讀取未配置的記憶體位置。

另請參閱

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

ReadInt32(Object, Int32)

來源:

Marshal.CoreCLR.cs

警告

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

從 Unmanaged 記憶體中指定位移處讀取 32 位元帶正負號的整數。

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

參數

ptr

Object

來源物件之 Unmanaged 記憶體中的基底位址。

ofs

Int32

額外的位元組位移，會先加入至參數 ptr，然後再進行讀取。

傳回

Int32

從 Unmanaged 記憶體中指定位移處讀取的 32 位元帶正負號的整數。

屬性

ObsoleteAttribute

例外狀況

AccessViolationException

基底位址 (ptr) 加上位移位元組 (ofs) 會產生 Null 或無效的位址。

ArgumentException

ptr 是 ArrayWithOffset 物件。 這個方法不會接受 ArrayWithOffset 參數。

備註

ReadInt32 可讓您直接與 Unmanaged 32 位帶正負號的陣列互動，避免在讀取其元素值之前，先將 Marshal.Copy 整個 Unmanaged 數位複製 () (。

支援讀取未配置的記憶體位置。

另請參閱

• Copy(Int32[], Int32, IntPtr, Int32)