Webcam api error when accessed from ASP.NET Server-side code
- by Eyla
I'm tring to use webcam api with asp.net and C#.
I included all the library and references I needed for that.
the original code I'm use was for windows application and I'm trying to convert it to asp.net web application.
I have start capturing button when I click it, it should start capturing but it gives me an error.
the error at this line:
hHwnd = capCreateCaptureWindowA(iDevice.ToString(), (WS_VISIBLE | WS_CHILD), 0, 0, 640, 480, picCapture.Handle.ToInt32(), 0);
and the error message is:
Error 1 'System.Web.UI.WebControls.Image' does not contain a definition for 'Handle' and no extension method 'Handle' accepting a first argument of type 'System.Web.UI.WebControls.Image' could be found (are you missing a using directive or an assembly reference?) C:\Users\Ali\Documents\Visual Studio 2008\Projects\Conference\Conference\Conference1.aspx.cs 63 117 Conference
Please advice!!
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here is the complete code
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using System;
using System.Collections;
using System.Drawing;
using System.ComponentModel;
using System.Windows.Forms;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Runtime.InteropServices;
using System.Drawing.Imaging;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.IO;
namespace Conference
{
public partial class Conference1 : System.Web.UI.Page
{
#region WebCam API
const short WM_CAP = 1024;
const int WM_CAP_DRIVER_CONNECT = WM_CAP + 10;
const int WM_CAP_DRIVER_DISCONNECT = WM_CAP + 11;
const int WM_CAP_EDIT_COPY = WM_CAP + 30;
const int WM_CAP_SET_PREVIEW = WM_CAP + 50;
const int WM_CAP_SET_PREVIEWRATE = WM_CAP + 52;
const int WM_CAP_SET_SCALE = WM_CAP + 53;
const int WS_CHILD = 1073741824;
const int WS_VISIBLE = 268435456;
const short SWP_NOMOVE = 2;
const short SWP_NOSIZE = 1;
const short SWP_NOZORDER = 4;
const short HWND_BOTTOM = 1;
int iDevice = 0;
int hHwnd;
[System.Runtime.InteropServices.DllImport("user32", EntryPoint = "SendMessageA")]
static extern int SendMessage(int hwnd, int wMsg, int wParam, [MarshalAs(UnmanagedType.AsAny)]
object lParam);
[System.Runtime.InteropServices.DllImport("user32", EntryPoint = "SetWindowPos")]
static extern int SetWindowPos(int hwnd, int hWndInsertAfter, int x, int y, int cx, int cy, int wFlags);
[System.Runtime.InteropServices.DllImport("user32")]
static extern bool DestroyWindow(int hndw);
[System.Runtime.InteropServices.DllImport("avicap32.dll")]
static extern int capCreateCaptureWindowA(string lpszWindowName, int dwStyle, int x, int y, int nWidth, short nHeight, int hWndParent, int nID);
[System.Runtime.InteropServices.DllImport("avicap32.dll")]
static extern bool capGetDriverDescriptionA(short wDriver, string lpszName, int cbName, string lpszVer, int cbVer);
private void OpenPreviewWindow()
{
int iHeight = 320;
int iWidth = 200;
//
// Open Preview window in picturebox
//
hHwnd = capCreateCaptureWindowA(iDevice.ToString(), (WS_VISIBLE | WS_CHILD), 0, 0, 640, 480, picCapture.Handle.ToInt32(), 0);
//
// Connect to device
//
if (SendMessage(hHwnd, WM_CAP_DRIVER_CONNECT, iDevice, 0) == 1)
{
//
// Set the preview scale
//
SendMessage(hHwnd, WM_CAP_SET_SCALE, 1, 0);
//
// Set the preview rate in milliseconds
//
SendMessage(hHwnd, WM_CAP_SET_PREVIEWRATE, 66, 0);
//
// Start previewing the image from the camera
//
SendMessage(hHwnd, WM_CAP_SET_PREVIEW, 1, 0);
//
// Resize window to fit in picturebox
//
SetWindowPos(hHwnd, HWND_BOTTOM, 0, 0, iWidth, iHeight, (SWP_NOMOVE | SWP_NOZORDER));
}
else
{
//
// Error connecting to device close window
//
DestroyWindow(hHwnd);
}
}
private void ClosePreviewWindow()
{
//
// Disconnect from device
//
SendMessage(hHwnd, WM_CAP_DRIVER_DISCONNECT, iDevice, 0);
//
// close window
//
DestroyWindow(hHwnd);
}
#endregion
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btnStart_Click(object sender, EventArgs e)
{
int iDevice = int.Parse(device_number_textBox.Text);
OpenPreviewWindow();
}
}
}
