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

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

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

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

Parameters

source
Type: System.Byte()

The one-dimensional array to copy from.

startIndex
Type: System.Int32

The zero-based index in the source array where copying should start.

destination
Type: System.IntPtr

The memory pointer to copy to.

length
Type: System.Int32

The number of array elements to copy.

ExceptionCondition
ArgumentOutOfRangeException

startIndex and length are not valid.

ArgumentNullException

source, startIndex, destination, or length is Nothing.

You can use this method to copy a subset of a one-dimensional managed array to an unmanaged C-style array.

The following example copies an array to unmanaged memory by using the Copy(Byte(), Int32, IntPtr, Int32) overload, and then copies the unmanaged array back to managed memory by using the Copy(IntPtr, Byte(), Int32, Int32) overload.

Imports System
Imports System.Runtime.InteropServices



Module Example


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

        ' Initialize unmanaged 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 copied to unmanaged memory and back.")

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

    End Sub 
End Module

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

  • SecurityCriticalAttribute 

    requires full trust for the immediate caller. This member cannot be used by partially trusted or transparent code.

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