Question

我需要在紧凑的框架3.7应用程序中通过从dll Aygshell.dll中对SHCameraCapture进行pinvoking来显示相机捕获对话框。由于我正在使用的技术的限制，我不能使用托管对象CameraCaptureDialog。相反，我需要通过Pinvoking来访问它。

有关该功能的文档，请参阅http://msdn.microsoft.com/en-us/library/aa454995.aspx。该函数接受一个定义对话框参数的结构。例如保存文件的位置，使用的分辨率。

我想成像，我必须在C＃中定义结构的副本，并使用StructLayout属性装饰sturct。我还想象代码会涉及[DllImport（“aygshell.dll”）]。如何调用此示例代码将非常感激。

Answer 1

此代码有效....

#region Enumerations

public enum CAMERACAPTURE_STILLQUALITY
{
    CAMERACAPTURE_STILLQUALITY_DEFAULT = 0,
    CAMERACAPTURE_STILLQUALITY_LOW = 1,
    CAMERACAPTURE_STILLQUALITY_NORMAL = 2,
    CAMERACAPTURE_STILLQUALITY_HIGH = 3
}
public enum CAMERACAPTURE_VIDEOTYPES
{
    CAMERACAPTURE_VIDEOTYPE_ALL = 0xFFFF,
    CAMERACAPTURE_VIDEOTYPE_STANDARD = 1,
    CAMERACAPTURE_VIDEOTYPE_MESSAGING = 2
}

public enum CAMERACAPTURE_MODE
{
    CAMERACAPTURE_MODE_STILL = 0,
    CAMERACAPTURE_MODE_VIDEOONLY = 1,
    CAMERACAPTURE_MODE_VIDEOWITHAUDIO = 2
}

#endregion //Enumerations

#region Structures

[StructLayout(LayoutKind.Sequential,CharSet=CharSet.Unicode)]
public struct struSHCAMERACAPTURE
{
    public uint cbSize;
    public IntPtr hwndOwner;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
    public String szFile;
    [MarshalAs(UnmanagedType.LPTStr)]
    public String pszInitialDir; //LPCTSTR
    [MarshalAs(UnmanagedType.LPTStr)]
    public String pszDefaultFileName; //LPCTSTR
    [MarshalAs(UnmanagedType.LPTStr)]
    public String pszTitle;  //LPCTSTR
    public CAMERACAPTURE_STILLQUALITY StillQuality;
    public CAMERACAPTURE_VIDEOTYPES VideoTypes;
    public uint nResolutionWidth;
    public uint nResolutionHeight;
    public uint nVideoTimeLimit;
    public CAMERACAPTURE_MODE Mode;
}
#endregion //Structures

#region API
[DllImport("Aygshell.dll", SetLastError = true,CharSet=CharSet.Unicode)]
public static extern int SHCameraCapture
(
    ref struSHCAMERACAPTURE pshCamCapture
);

private string StartImager(String strImgDir, String strImgFile, uint uintImgHeight,
                            uint uintImgWidth)

try
{
  struSHCAMERACAPTURE shCamCapture = new struSHCAMERACAPTURE();

  shCamCapture.cbSize = (uint)Marshal.SizeOf(shCamCapture);
  shCamCapture.hwndOwner = IntPtr.Zero;
  shCamCapture.szFile = "\\" + strImgFile;  //strImgDir + "\\" + strImgFile;
  shCamCapture.pszInitialDir = "\\"; // strImgDir;
  shCamCapture.pszDefaultFileName = strImgFile;
  shCamCapture.pszTitle = "PTT Image Capture";
  shCamCapture.StillQuality = 0; // CAMERACAPTURE_STILLQUALITY.CAMERACAPTURE_STILLQUALITY_NORMAL;
  shCamCapture.VideoTypes = CAMERACAPTURE_VIDEOTYPES.CAMERACAPTURE_VIDEOTYPE_STANDARD;
  shCamCapture.nResolutionHeight = 0; // uintImgHeight;
  shCamCapture.nResolutionWidth = 0; // uintImgWidth;
  shCamCapture.nVideoTimeLimit = 10;
  shCamCapture.Mode = 0; // CAMERACAPTURE_MODE.CAMERACAPTURE_MODE_STILL;

  //IntPtr intptrCamCaptr = IntPtr.Zero;

  //Marshal.StructureToPtr(shCamCapture, intptrCamCaptr, true);

  int intResult = SHCameraCapture(ref shCamCapture);
  if (intResult != 0)
  {
      Win32Exception Win32 = new Win32Exception(intResult);
      MessageBox.Show("Error: " + Win32.Message);
  }             

  return strCaptrErr;
}

catch (Exception ex)
{
    MessageBox.Show("Error StartImager : " + ex.ToString() + " - " + strCaptrErr
                    , "Nomad Imager Test");
    return "";
}

Answer 2

Groky，这是一个良好的开端......感谢您的开始。我尝试连接它，但得到一个NotSupportedException。

我已粘贴下面测试应用中的文字。请注意，我尝试使用[StructLayout（LayoutKind.Sequential）]装饰结构。我还公开了所有成员，以消除对象可访问性方面的任何问题。

public partial class Form1 : Form
{
    [DllImport("aygshell.dll")]
    static extern int SHCameraCapture(ref SHCAMERACAPTURE pshcc);

    [StructLayout(LayoutKind.Sequential)]
    struct SHCAMERACAPTURE
    {
        public Int32 cbSize;
        public IntPtr hwndOwner;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
        public string szFile;
        [MarshalAs(UnmanagedType.LPStr)]
        public string pszInitialDir;
        [MarshalAs(UnmanagedType.LPStr)]
        public string pszDefaultFileName;
        [MarshalAs(UnmanagedType.LPStr)]
        public string pszTitle;
        public Int32 StillQuality;
        public Int32 VideoTypes;
        public Int32 nResolutionWidth;
        public Int32 nResolutionHeight;
        public Int32 nVideoTimeLimit;
        public Int32 Mode;
    }
    private void ShowCamera()
    {
        SHCAMERACAPTURE captureData = new SHCAMERACAPTURE
                                           {
                                               cbSize = sizeof (Int64),
                                               hwndOwner = (IntPtr)0,
                                               szFile = "\\My Documents",
                                               pszDefaultFileName = "picture.jpg",
                                               pszTitle = "Camera Demo",
                                               StillQuality = 0,
                                               VideoTypes = 1,
                                               nResolutionWidth = 480,
                                               nResolutionHeight = 640,
                                               nVideoTimeLimit = 0,
                                               Mode = 0
                                           };
        SHCameraCapture(ref captureData);
    }
    private void button1_Click(object sender, EventArgs e)
    {
        ShowCamera();
    }

Answer 3

我无法对此进行测试，但您的结构/函数看起来应该是这样的：

struct SHCAMERACAPTURE {
  public Int32 cbSize;
  public IntPtr hwndOwner;

  [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]  
  public string szFile;

  [MarshalAs(UnmanagedType.LPStr)] 
  string pszInitialDir;

  [MarshalAs(UnmanagedType.LPStr)] 
  string pszDefaultFileName;

  [MarshalAs(UnmanagedType.LPStr)] 
  string pszTitle;

  Int32 StillQuality;
  Int32 VideoTypes;
  Int32 nResolutionWidth;
  Int32 nResolutionHeight;
  Int32 nVideoTimeLimit;
  Int32 Mode;
}

[DllImport("aygshell.dll")]
static extern int SHCameraCapture(ref SHCAMERACAPTURE pshcc);

AFAIK，你不需要在SHCAMERCAPTURE上显式设置StructLayout，因为它的布局没有什么异常。

一旦你开始工作，你可能想把你的发现发布到pinvoke.net上供其他人使用！

如何从WinMO6的Aygshell.dll中调用函数SHCameraCapture（相机对话框）

3 个答案: