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Marshal.Copy Method (IntPtr, Byte[], Int32, Int32)

Copies data from an unmanaged memory pointer to a managed 8-bit unsigned integer array.

Namespace: System.Runtime.InteropServices
Assembly: mscorlib (in mscorlib.dll)

'Declaration
Public Shared Sub Copy ( _
	source As IntPtr, _
	destination As Byte(), _
	startIndex As Integer, _
	length As Integer _
)
'Usage
Dim source As IntPtr
Dim destination As Byte()
Dim startIndex As Integer
Dim length As Integer

Marshal.Copy(source, destination, startIndex, length)
public static void Copy (
	IntPtr source, 
	byte[] destination, 
	int startIndex, 
	int length
)
public static function Copy (
	source : IntPtr, 
	destination : byte[], 
	startIndex : int, 
	length : int
)

Parameters

source

The memory pointer to copy from.

destination

The array to copy to.

startIndex

The zero-based index into the array where Copy should start.

length

The number of array elements to copy.

Exception typeCondition

ArgumentNullException

source, destination, startIndex, or length is a null reference (Nothing in Visual Basic).

Unmanaged, C-style arrays do not contain bounds information, which prevents the startIndex and length parameters from being validated. Thus, the unmanaged data corresponding to the source parameter populates the managed array regardless of its usefulness. You must initalize the managed array with the appropriate size before calling the Marshal.Copy method.

NoteNote

This method uses SecurityAction.LinkDemand to prevent it from being called from untrusted code; only the immediate caller is required to have SecurityPermissionAttribute.UnmanagedCode permission. If your code can be called from partially trusted code, do not pass user input to Marshal class methods without validation. For important limitations on using the LinkDemand member, see Demand vs. LinkDemand.

The following code example copies an array to unmanaged memory and then copies the unmanaged array back to managed memory.

Imports System
Imports System.Runtime.InteropServices



Module Example


    Sub Main()
        ' Create a managed array.
        Dim managedArray As Byte() = {1, 2, 3, 4}

        ' Initialize unmanged memory to hold the array.
        Dim size As Integer = Marshal.SizeOf(managedArray(0)) * managedArray.Length

        Dim pnt As IntPtr = Marshal.AllocHGlobal(size)

        Try
            ' Copy the array to unmanaged memory.
            Marshal.Copy(managedArray, 0, pnt, managedArray.Length)

            ' Copy the unmanaged array back to another managed array.
            Dim managedArray2(managedArray.Length) As Byte

            Marshal.Copy(pnt, managedArray2, 0, managedArray.Length)

            Console.WriteLine("The array was coppied to unmanaged memory and back.")

        Finally
            ' Free the unmanaged memory.
            Marshal.FreeHGlobal(pnt)
        End Try

    End Sub
End Module



Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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