如何在VB.Net中使用不安全的代码？

我想知道VB.NET相当于以下C＃代码：

unsafe { byte* pStart = (byte*)(void*)writeableBitmap.BackBuffer; int nL = writeableBitmap.BackBufferStride; for (int r = 0; r < 16; r++) { for (int g = 0; g < 16; g++) { for (int b = 0; b < 16; b++) { int nX = (g % 4) * 16 + b; int nY = r*4 + (int)(g/4); *(pStart + nY*nL + nX*3 + 0) = (byte)(b * 17); *(pStart + nY*nL + nX*3 + 1) = (byte)(g * 17); *(pStart + nY*nL + nX*3 + 2) = (byte)(r * 17); } } } } 

Answer 1

看起来不可能。

从这篇文章

在这方面，VB.NET比C＃更具限制性。 它不允许在任何情况下使用不安全的代码。

Answer 2

不可能，因为vb.net不支持不安全的代码。

Answer 3

VB.NET不允许使用不安全的代码，但您可以安全地管理您的代码：

 Dim pStart As IntPtr = AddressOf (writeableBitmap.BackBuffer()) Dim nL As Integer = writeableBitmap.BackBufferStride For r As Integer = 0 To 15 For g As Integer = 0 To 15 For b As Integer = 0 To 15 Dim nX As Integer = (g Mod 4) * 16 + b Dim nY As Integer = r * 4 + CInt(g \ 4) Marshal.WriteInt32((pStart + nY * nL + nX * 3 + 0),(b * 17)) Marshal.WriteInt32((pStart + nY * nL + nX * 3 + 1),(g * 17)) Marshal.WriteInt32((pStart + nY * nL + nX * 3 + 2),(r * 17)) Next Next Next 

Answer 4

您可以使用此安全代码获得相同的结果

 Dim pStart As Pointer(Of Byte) = CType(CType(writeableBitmap.BackBuffer, Pointer(Of System.Void)), Pointer(Of Byte)) Dim nL As Integer = writeableBitmap.BackBufferStride For r As Integer = 0 To 15 For g As Integer = 0 To 15 For b As Integer = 0 To 15 Dim nX As Integer = (g Mod 4) * 16 + b Dim nY As Integer = r * 4 + CInt(g \ 4) (pStart + nY * nL + nX * 3 + 0).Target = CByte(b * 17) (pStart + nY * nL + nX * 3 + 1).Target = CByte(g * 17) (pStart + nY * nL + nX * 3 + 2).Target = CByte(r * 17) Next Next Next