How to use DllImport in VB NET

Question

How should I DLLImport things in VB NET  An example would be    lt DllImport  user32 dll   SetLastError  True  CharSet  CharSet Auto  gt    Private Shared Function GetWindowText ByVal hwnd As IntPtr  ByVal lpString As StringBuilder  ByVal cch As Integer  As Integer  End Function   If I put it inside a Class or somewhere else  I get  DLLimport is not defined  I am using Visual nbsp Studio nbsp 2008 Professional

User · Answer

I saw in getwindowtext  user32  on pinvoke net that you can place a MarshalAs statement to state that the StringBuffer is equivalent to LPSTR    lt DllImport  user32 dll   SetLastError  True  CharSet  CharSet Ansi  gt    Public Function GetWindowText hwnd As IntPtr   lt MarshalAs UnManagedType LPStr  gt lpString As System Text StringBuilder  cch As Integer  As Integer End Function

User · Answer

You can also try this  Private Declare Function GetWindowText Lib  user32 dll   ByVal hwnd As IntPtr  ByVal lpString As StringBuilder  ByVal cch As Integer  As Integer   I always use Declare Function instead of DllImport    Its more simply  its shorter and does the same

User · Answer

Imports System Runtime InteropServices

User · Answer

I know this has already been answered  but here is an example for the people who are trying to use SQL Server Types in a vb project               Imports System             Imports System IO             Imports System Runtime InteropServices              Namespace SqlServerTypes                 Public Class Utilities                         lt DllImport  kernel32 dll   CharSet  CharSet Auto  SetLastError  True  gt                      Public Shared Function LoadLibrary ByVal libname As String  As IntPtr                      End Function                      Public Shared Sub LoadNativeAssemblies ByVal rootApplicationPath As String                          Dim nativeBinaryPath   If IntPtr Size  gt  4  Path Combine rootApplicationPath   SqlServerTypes x64     Path Combine rootApplicationPath   SqlServerTypes x86                             LoadNativeAssembly nativeBinaryPath   msvcr120 dll                           LoadNativeAssembly nativeBinaryPath   SqlServerSpatial140 dll                       End Sub                      Private Shared Sub LoadNativeAssembly ByVal nativeBinaryPath As String  ByVal assemblyName As String                          Dim path   System IO Path Combine nativeBinaryPath  assemblyName                          Dim ptr   LoadLibrary path                           If ptr   IntPtr Zero Then                             Throw New Exception String Format  Error loading  0   ErrorCode   1     assemblyName  Marshal GetLastWin32Error                             End If                     End Sub                 End Class             End Namespace

User · Answer

You have to add Imports System Runtime InteropServices to the top of your source file   Alternatively  you can fully qualify attribute name    lt System Runtime InteropService DllImport  user32 dll         SetLastError  True  CharSet  CharSet Auto  gt

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