C++到vb.net，回調函數的問題

Question

我很難在這裏試圖找到我的問題的解決方案。

我想將客戶端API功能從C++轉換爲VB.NET， ，我認爲回調函數有一些問題。 C++代碼的

部分：

typedef結構{

BYTE m_bRemoteChannel; 
BYTE m_bSendMode; 
BYTE m_nImgFormat; // =0 cif ; = 1 qcif 
char *m_sIPAddress; 
char *m_sUserName; 
char *m_sUserPassword; 
BOOL m_bUserCheck; 
HWND m_hShowVideo; 

} CLIENT_VIDEOINFO，* PCLIENT_VIDEOINFO; （PCLIENT_VIDEOINFO pClientinfo，void（CALLBACK * ReadDataCallBack）（DWORD nPort，UCHAR * pPacketBuffer，DWORD nPacketSize））;}};

空隙CALLBACK ReadDataCallBack（DWORD NPORT，UCHAR * pPacketBuffer，DWORD nPacketSize）

{ TRACE（ 「％d \ n」 個，nPacketSize）; }

..... 
aa5.m_sUserName = "123"; 
aa5.m_sUserPassword="w"; 
aa5.m_bUserCheck = TRUE; 

MP4_ClientSetTTL(64); 
nn1 = MP4_ClientStart(&aa5,ReadDataCallBack); 
if (nn1 == -1) 
{ 
    MessageBox("error"); 
    return; 
} 

---

SDK描述：

MP4_ClientStart

該函數啓動的連接。調用的格式爲：

LONG __stdcall MP4_ClientStart（PCLIENT_VIDEOINFO pClientinfo， 無效（* ReadDataCallBack）（DWORD N溝道，UCHAR * pPacketBuffer，DWORD nPacketSize））

參數 pClientinfo保存的信息。這個連接。

nChannel擁有卡的頻道。

pPacketBuffer保持指針到接收緩衝區。

nPacketSize保持接收緩衝器的長度。

返回值 如果函數成功返回值是這方面的內容。 如果函數失敗，則返回值爲-1。

備註

typedef結構{

BYTE m_bRemoteChannel;

BYTE m_bSendMode;

BYTE m_bImgFormat;

char * m_sIPAddress;

char * m_sUserName;

char * m_sUserPassword;

BOOL m_bUserCheck;

HWND m_hShowVideo;

} CLIENT_VIDEOINFO，* PCLIENT_VIDEOINFO;

m_bRemoteChannel保存客戶端想要連接的通道。

m_bSendMode保存連接的網絡模式。

m_bImgFormat：圖像格式，0是主頻道視頻，1是子通道視頻

m_sIPAddress保存服務器的IP地址。

m_sUserName保存用戶名。

m_sUserPassword保存用戶密碼。

m_bUserCheck保存是否發送用戶名和密碼的值。

m_hShowVideo包含此視頻窗口的句柄。

如果m_hShowVideo包含NULL，則客戶端可以僅在沒有解碼器的情況下進行記錄。

如果m_bUserCheck爲FALSE，我們將發送m_sUserName和m_sUserPassword作爲NULL，否則我們會發送每個50個字節。

m_sIPAddress和m_sUserName的長度必須大於50個字節。

ReadDataCallBack：當庫從服務器接收到數據包時，調用此回調函數。

---

我VB.Net代碼：

進口System.Runtime。InteropServices

公共類Form1中

Const WM_USER = &H400 

Public Structure CLIENT_VIDEOINFO 
    Public m_bRemoteChannel As Byte 
    Public m_bSendMode As Byte 
    Public m_bImgFormat As Byte 
    Public m_sIPAddress As String 
    Public m_sUserName As String 
    Public m_sUserPassword As String 
    Public m_bUserCheck As Boolean 
    Public m_hShowVideo As Long 'hWnd      
End Structure 


Public Declare Function MP4_ClientSetNetPort Lib "hikclient.dll" (ByVal dServerPort As Integer, ByVal dClientPort As Integer) As Boolean 
Public Declare Function MP4_ClientStartup Lib "hikclient.dll" (ByVal nMessage As UInteger, ByVal hWnd As System.IntPtr) As Boolean 


<DllImport("hikclient.dll")> Public Shared Function MP4_ClientStart(ByVal Clientinfo As CLIENT_VIDEOINFO, ByRef ReadDataCallBack As CALLBACKdel) As Long 
End Function 


Public Delegate Sub CALLBACKdel(ByVal nPort As Long, <MarshalAs(UnmanagedType.LPArray)> ByRef pPacketBuffer As Byte(), ByVal nPacketSize As Long) 


Public Sub CALLBACK(ByVal nPort As Long, <MarshalAs(UnmanagedType.LPArray)> ByRef pPacketBuffer As Byte(), ByVal nPacketSize As Long) 
End Sub 


Public mydel As New CALLBACKdel(AddressOf CALLBACK) 


Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 

    Dim Clientinfo As New CLIENT_VIDEOINFO() 
    Clientinfo.m_bRemoteChannel = 0 
    Clientinfo.m_bSendMode = 0 
    Clientinfo.m_bImgFormat = 0 
    Clientinfo.m_sIPAddress = "193.168.1.100" 
    Clientinfo.m_sUserName = "1" 
    Clientinfo.m_sUserPassword = "a" 
    Clientinfo.m_bUserCheck = False 
    Clientinfo.m_hShowVideo = Me.Handle 'Nothing 


    MP4_ClientSetNetPort(850, 850) 
    MP4_ClientStartup(WM_USER + 1, Me.Handle) 

    MP4_ClientStart(Clientinfo, mydel) 
End Sub 

末級

---

這裏是代碼的一些其他的例子：

C＃

http://blog.csdn.net/nenith1981/archive/2007/09/17/1787692.aspx

VB

：//read.pudn.com/downloads70/sourcecode/graph/250633/MD%E5%AE%A2%E6%88%B7%E7%AB%AF%28VB%29/hikclient。 bas __。htm

：//read.pudn.com/downloads70/sourcecode/graph/250633/MD%E5%AE%A2%E6%88%B7%E7%AB%AF%28VB%29/Form1。 。FRM __ HTM

德爾福

：//read.pudn.com/downloads91/sourcecode/multimedia/streaming/349759/Delphi_client/Unit1.pas__.htm

Answer 1

這並不是一個完整的解決方案你的問題，但我會開始添加StructLayoutAttribute（順序）到你的結構。

Imports System.Runtime.InteropServices 

<StructLayout(LayoutKind.Sequential)> _ 
Public Structure CLIENT_VIDEOINFO