Utiliser DLL C en VB

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Bonjour, Je pense que ce probleme a deja etait aborde plusieurs fois mais apres avoir cherche partout je ne trouve toujours pas la reponse a mon probleme. Je souhaite utiliser un dll detaillant une methode de calcul pour l implementer dans un programme en VB. Je cherche donc a utiliser les fonctions qui se trouvent dans le dll. Le probleme est la correspondance des types. Je souhaite pour l instant simplement adapter un simple exemple d utilisation du dll en C dans un environnement VB. L exemple est tres simple en C : Code : void* p2p ; double att[27] ; // initialize the PointToPoint module p2p = P2P_Create() ; if(p2p == NULL) { ... // error handling : could not create a P2P structure } // setup the cross-section // remember : the origin = point on the road surface below the source P2P_Clear(p2p) ; // source foot point (0,0) P2P_AddSegment (p2p, 10.0, 0.0, 7) ; // top of embankment P2P_AddSegment (p2p, 14.0, -3.0, 5) ; // bottom of embankment P2P_AddSegment (p2p, 50.0, -3.0, 4) ; // receiver foot point // set the source and receiver heights relative to the local terrain // heights at the first and last points of the cross-section P2P_SetSourceHeight (p2p, 0.3, 0.0) ; P2P_SetReceiverHeight (p2p, 5.0, 0.0) ; // calculate the excess attenuation and return the result in “att” P2P_GetResult (p2p, att) ; // do something with the excess attenuation values... Mon code VB est le suivant : Code : Private Declare Function Create Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_Create"() As Integer Private Declare Function Clear Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_Clear"(ByRef p2p_struct As Integer) As Integer Private Declare Function AddSegment Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_AddSegment"(ByRef p2p_struct As Integer, ByVal D As Double, ByVal Z As Double, ByVal impedanceModel As Integer) As Integer Private Declare Function SetSourceHeight Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_SetSourceHeight"(ByRef p2p_struct As Integer, ByVal hSource As Double, ByVal delta_hs As Double) As Integer Private Declare Function SetReceiverHeight Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_SetReceiverHeight"(ByRef p2p_struct As Integer, ByVal hRec As Double, ByVal delta_hRec As Double) As Integer Private Declare Function GetResults Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_GetResults"(ByRef p2p_struct As Integer, ByRef att_dB As Double) As Integer Private Declare Function Delete Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_Delete"(ByRef p2p_struct As Integer) Sub Main() Dim p2p As Integer p2p = Create() Clear(p2p) AddSegment(p2p, 10.0, 10.0, 1) 'AddSegment(p2p, 14.0, -3.0, 5) 'AddSegment(p2p, 50.0, -3.0, 4) 'SetSourceHeight(p2p, 0.3, 0.0) 'SetReceiverHeight(p2p, 5.0, 0.0) ' Dim att(0 To 27) As Double 'GetResults(p2p, att(0)) End Sub J obtiens un message d erreur du type : Citation: The runtime has encountered a fatal error. The address of the error was at 0x79e784b6, on thread 0xc78. The error code is 0xc0000005. This error may be a bug in the CLR or in the unsafe or non-verifiable portions of user code. Common sources of this bug include user marshaling errors for COM-interop or PInvoke, which may corrupt the stack. La fonction AddSegment fait planter le tout. Je pense que cela provient du fait que toutes les fonctions attendent un void* et que moi je passe un Integer Byref. Je ne sais pas quoi faire. Si quelqu un peut m aider Please....

ncyshaolin · Answer

J ai change mon code en : Imports System.Runtime.InteropServices Module Module1 Private Declare Function Create Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_Create" () As Integer Private Declare Function Clear Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_Clear" ( ByVal p2p_struct As Object) As Integer Private Declare Function AddSegment Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_AddSegment" ( ByVal p2p_struct As Object, ByVal D As Double, ByVal Z As Double, ByVal impedanceModel As Integer) As Integer Private Declare Function SetSourceHeight Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_SetSourceHeight" ( ByVal p2p_struct As Object, ByVal hSource As Double, ByVal delta_hs As Double) As Integer Private Declare Function SetReceiverHeight Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_SetReceiverHeight" ( ByVal p2p_struct As Object, ByVal hRec As Double, ByVal delta_hRec As Double) As Integer Private Declare Function GetResults Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_GetResults" ( ByVal p2p_struct As Object, ByVal att_dB As Double) As Integer Private Declare Function Delete Lib "C:\Documents and Settings\guerini-grossc\My Documents\PointToPoint.dll" Alias "P2P_Delete" ( ByVal p2p_struct As Object) As Integer Sub Main() Dim p2p As Object Dim att(0 To 100) As Double p2p = Create() Clear(p2p) AddSegment(p2p, 10.0, 10.0, 1) AddSegment(p2p, 14.0, -3.0, 5) AddSegment(p2p, 50.0, -3.0, 4) SetSourceHeight(p2p, 0.3, 0.0) SetReceiverHeight(p2p, 5.0, 0.0) 'GetResults(p2p, att(0)) Delete(p2p) Dim i As Integer For i = 0 To att.GetUpperBound(0) Console.WriteLine("att(" & i & ") = " & att(i)) Next i Dim ligne As String = Console.In.ReadLine() End Sub End Module Il semble que cela marche sauf la fonction principale GetResults qui cause une erreur de type : Attempted to read or write protected memory. This is often an indication that other memory is corrupt. Les changements que j ai effectue proviennent de ce que j ai pu trouver sur les aides de microsoft bien que je ne comprenne pas ce qui se passe vraiment. J attends de l aide de votre part.

lesdis · Answer

Bonjour,

Si je ne m'abuse, il faut aller voir du coté de la classe MarshalLes pointeurs en Vb sont normalement définis par la structure IntPtrBonne Prog

Utiliser DLL C en VB

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