Visual Basic

Imports System<br />
Imports System.Runtime.InteropServices<br />
Imports System.Resources<br />
Imports System.IO<br />
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' The SNAPI.dll is an unmanaged DLL written in C++ and we only have available the SNAPI.dll, the SNAPI.lib and the SNAPI.h<br />
Declare Auto Function SNAPI_Init Lib "SNAPI.dll" (ByVal HWND As IntPtr, ByRef DeviceHandle As IntPtr, ByRef NumDevices As IntPtr) As Integer<br />
Declare Auto Function SNAPI_Connect Lib "SNAPI.dll" (ByVal DeviceHandle As IntPtr) As Integer<br />
Declare Auto Function SNAPI_Disconnect Lib "SNAPI.dll" (ByVal DeviceHandle As IntPtr) As Integer<br />
Declare Auto Function SNAPI_GetSerialNumber Lib "SNAPI.dll" (ByVal DeviceHandle As IntPtr, <MarshalAs(UnmanagedType.SysInt)> ByRef SerialNo As IntPtr) As Integer<br />
Declare Auto Function SNAPI_SoundBeeper Lib "SNAPI.dll" (ByVal DeviceHandle As IntPtr, ByRef nBeepCode As Byte) As Integer<br />
Declare Auto Function SNAPI_SetVersionBuffer Lib "SNAPI.dll" (ByVal DeviceHandle As IntPtr, ByRef DataPtr As IntPtr, ByVal max_length As Int32) As Integer<br />
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'Handles and Messages<br />
Dim Status As Int32 = 0<br />
Dim devhandle As IntPtr<br />
Dim numdev As IntPtr<br />
Dim serialno(255) As Byte<br />
Dim resultStr As String<br />
Dim ptr As IntPtr = Marshal.AllocHGlobal(256)<br />
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' These are some beep codes for the beep functions<br />
Const ONESHORTHI As Byte = &H0<br />
Const TWOSHORTHI As Byte = &H1<br />
Const THREESHORTHI As Byte = &H2<br />
Const FOURSHORTHI As Byte = &H3<br />
Const FIVESHORTHI As Byte = &H4<br />
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'C++ Definitions in SNAPI.H<br />
'SNAPIDLL_API int  __stdcall SNAPI_Connect(HANDLE   DeviceHandle)<br />
'SNAPIDLL_API int	__stdcall SNAPI_Init(HWND hwnd, HANDLE  * DeviceHandles, int * NumDevices)<br />
'SNAPIDLL_API int __stdcall SNAPI_Disconnect(HANDLE   DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_SnapShot(HANDLE DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_TransmitVersion(HANDLE DeviceHandle)<br />
'/*SNAPIDLL_API int __stdcall AbortImageXfer(HANDLE DeviceHandle)*/<br />
'SNAPIDLL_API int __stdcall SNAPI_PullTrigger(HANDLE DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_ReleaseTrigger(HANDLE DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_SetParameters(WORD *Params, int ParamWords, HANDLE DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_TransmitVideo(HANDLE DeviceHandle) <br />
'SNAPIDLL_API int __stdcall SNAPI_RequestParameters(WORD *Params, int ParamWords, HANDLE DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_RequestAllParameters(HANDLE DeviceHandle)<br />
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'SNAPIDLL_API int __stdcall SNAPI_AimOn(HANDLE DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_AimOff(HANDLE DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_LedOn(HANDLE DeviceHandle, unsigned char nLEDselection)<br />
'SNAPIDLL_API int __stdcall SNAPI_LedOff(HANDLE DeviceHandle, unsigned char nLEDselection)<br />
'SNAPIDLL_API int __stdcall SNAPI_ScanEnable(HANDLE DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_ScanDisable(HANDLE DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_SoundBeeper(HANDLE DeviceHandle, unsigned char nBeepCode)<br />
'SNAPIDLL_API int __stdcall SNAPI_EnterLowPwrMode(HANDLE DeviceHandle)<br />
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'SNAPIDLL_API int __stdcall SNAPI_RequestScannerCapabilities(HANDLE DeviceHandle)<br />
'SNAPIDLL_API int __stdcall SNAPI_SetParamPersistance(HANDLE DeviceHandle, int bPersist)<br />
'SNAPIDLL_API int __stdcall SNAPI_AbortMacroPdf(HANDLE DeviceHandle)  // aborts macro session and throws out any data<br />
'SNAPIDLL_API int __stdcall SNAPI_FlushMacroPdf(HANDLE DeviceHandle)  // aborts macro session and sends any data<br />
'SNAPIDLL_API int __stdcall SNAPI_SetParameterDefaults(HANDLE DeviceHandle)<br />
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'SNAPIDLL_API unsigned int __stdcall SNAPI_ReturnDLLVersion(void)<br />
'SNAPIDLL_API int __stdcall SNAPI_GetSerialNumber(HANDLE DeviceHandle,unsigned char * SerialNo)<br />
'                                                  // aborts macro session and sends any data<br />
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'SNAPIDLL_API int __stdcall SNAPI_SetVideoBuffer(HANDLE DeviceHandle, unsigned char *pData, long max_length)<br />
'SNAPIDLL_API int __stdcall SNAPI_SetImageBuffer(HANDLE DeviceHandle, unsigned char *pData, long max_length)<br />
'SNAPIDLL_API int __stdcall SNAPI_SetDecodeBuffer(HANDLE DeviceHandle, unsigned char *pData, long max_length)<br />
'SNAPIDLL_API int __stdcall SNAPI_SetVersionBuffer(HANDLE DeviceHandle, unsigned char *pData, long max_length)<br />
'SNAPIDLL_API int __stdcall SNAPI_SetCapabilitiesBuffer(HANDLE DeviceHandle, unsigned char *pData, long max_length)<br />
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'This is the First Subroutine to be called<br />
Private Sub cmdSNAPI_Init_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SNAPI_Init.Click<br />
  Status = SNAPI_Init(WinHandle, devhandle, numdev).ToString<br />
End Sub<br />
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'This is the Second Subroutine to be called<br />
'It then calls SNAPI_GetSerialNumber to obtain the serial number from the SYMBOL DS6607 Barcode scanner<br />
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Private Sub cmdSNAPI_Connect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdConnect.Click<br />
  lblConnect.Text = SNAPI_Connect(devhandle).ToString<br />
  lblDLLVer.Text = "DLL Version: " & SNAPI_ReturnDLLVersion()<br />
  Status = SNAPI_GetSerialNumber(devhandle, ptr)<br />
  resultStr = Marshal.PtrToStringAuto(ptr, 256)<br />
'@@@@@@@@@@@@@@ I get a ATTEMPTED TO READ OR WRITE PROTECTED MEMORY at this point, any suggestions ?  @@@@@@@@@@@@@@<br />
End Sub<br />
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'This is the Last Subroutine to be called to Disconnect from the SYMBOL DS6607 Barcode scanner<br />
Private Sub cmdSNAPI_Disconnect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSNAPI_Disconnect.Click<br />
  Status = SNAPI_Disconnect(devhandle)<br />
End Sub<br />
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Private Sub cmdSNAPI_SoundBeeper_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSNAPI_SoundBeeper.Click<br />
  Status = SNAPI_SoundBeeper(devhandle, FIVESHORTHI)<br />
End Sub