C＃COM互操作与Windows Media Player可视化（示例代码） [英] C# Com Interop with Windows Media Player Visualisation (With Sample Code)
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问题描述
我试图创建在C＃中的Windows Media Player（WMP）可视化插件。我很新揭露的C＃COM和可能错过了一些基本的东西。我跟这个持续了3天（约20小时），并没有得到过去单一的问题，我将在下面介绍。
I am attempting to create a Windows Media Player (WMP) Visualization plugin in C#. I am quite new to exposing C# to COM and may have missed something basic. I have persisted with this for 3 days (about 20 hours) and not got past the single issue I will describe below.
对于那些谁也不知道，WMP可视化，是在媒体播放器显示边听音乐漂亮的图片
For those who don't know, WMP visualizations are the pretty images that show in media player while listening to music.
简而言之：WMP会打电话给我的C＃COM接口上的某些方法，而不是其他。
In a nutshell: WMP will call certain methods on my C# COM interface, but not others.
我有WMP 11安装
我下载了最新的 Windows SDK的其中包含了C ++插件向导编译工作的可视化样本。此示例寄存器和工作没有在WMP的问题。
I downloaded the Latest Windows SDK which contains a C++ plugin wizard to compile a working visualization sample. This sample registers and works without issues in WMP.
该开发套件包含一个名为effects.h C ++头文件，它包含2接口，必须实现以获得插件与WMP工作。它似乎没有多少比这更复杂
The dev kit contains a C++ header file named effects.h that contains 2 interfaces that must be implemented to get the plugin to work with WMP. It doesn't appear to much more complicated than that.
下面它们
MIDL_INTERFACE("D3984C13-C3CB-48e2-8BE5-5168340B4F35")
IWMPEffects : public IUnknown
{
public:
virtual /* [helpstring][local] */ HRESULT STDMETHODCALLTYPE Render(
/* [in] */ TimedLevel *pLevels,
/* [in] */ HDC hdc,
/* [in] */ RECT *prc) = 0;
virtual /* [helpstring] */ HRESULT STDMETHODCALLTYPE MediaInfo(
/* [in] */ LONG lChannelCount,
/* [in] */ LONG lSampleRate,
/* [in] */ BSTR bstrTitle) = 0;
virtual /* [helpstring] */ HRESULT STDMETHODCALLTYPE GetCapabilities(
/* [out] */ DWORD *pdwCapabilities) = 0;
virtual /* [helpstring] */ HRESULT STDMETHODCALLTYPE GetTitle(
/* [out] */ BSTR *bstrTitle) = 0;
virtual /* [helpstring] */ HRESULT STDMETHODCALLTYPE GetPresetTitle(
/* [in] */ LONG nPreset,
/* [out] */ BSTR *bstrPresetTitle) = 0;
virtual /* [helpstring] */ HRESULT STDMETHODCALLTYPE GetPresetCount(
/* [out] */ LONG *pnPresetCount) = 0;
virtual /* [helpstring] */ HRESULT STDMETHODCALLTYPE SetCurrentPreset(
/* [in] */ LONG nPreset) = 0;
virtual /* [helpstring] */ HRESULT STDMETHODCALLTYPE GetCurrentPreset(
/* [out] */ LONG *pnPreset) = 0;
virtual /* [helpstring] */ HRESULT STDMETHODCALLTYPE DisplayPropertyPage(
/* [in] */ HWND hwndOwner) = 0;
virtual /* [helpstring] */ HRESULT STDMETHODCALLTYPE GoFullscreen(
/* [in] */ BOOL fFullScreen) = 0;
virtual /* [helpstring] */ HRESULT STDMETHODCALLTYPE RenderFullScreen(
/* [in] */ TimedLevel *pLevels) = 0;
};
MIDL_INTERFACE("695386EC-AA3C-4618-A5E1-DD9A8B987632")
IWMPEffects2 : public IWMPEffects
{
public:
virtual HRESULT STDMETHODCALLTYPE SetCore(
/* [in] */ IWMPCore *pPlayer) = 0;
virtual HRESULT STDMETHODCALLTYPE Create(
/* [in] */ HWND hwndParent) = 0;
virtual HRESULT STDMETHODCALLTYPE Destroy( void) = 0;
virtual HRESULT STDMETHODCALLTYPE NotifyNewMedia(
/* [in] */ IWMPMedia *pMedia) = 0;
virtual HRESULT STDMETHODCALLTYPE OnWindowMessage(
/* [in] */ UINT msg,
/* [in] */ WPARAM WParam,
/* [in] */ LPARAM LParam,
/* [in] */ LRESULT *plResultParam) = 0;
virtual HRESULT STDMETHODCALLTYPE RenderWindowed(
/* [in] */ TimedLevel *pData,
/* [in] */ BOOL fRequiredRender) = 0;
};
正如我所说，我的COM知识，我不是最好的。这是我做过什么将它移植到C＃。
As I mentioned, my COM knowledge my not be the best. This is what I did to port it to C#.
我转换的接口以下
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
namespace WmpTestPlugin
{
[ComVisible(true)]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[Guid("D3984C13-C3CB-48e2-8BE5-5168340B4F35")]
public interface IWmpEffects
{
int Render(ref TimedLevel pLevels, IntPtr Hdc, ref RECT pRC);
int MediaInfo(int lChannelCount, int lSampleRate, string bstrTitle);
int GetCapabilities(ref int pdwCapabilities);
int GetTitle(ref string bstrTitle);
int GetPresetTitle([In] int nPreset, [MarshalAs(UnmanagedType.BStr)] ref string bstrPresetTitle);
int GetPresetCount(ref int count);
int SetCurrentPreset(int currentpreset);
int GetCurrentPreset(ref int currentpreset);
int DisplayPropertyPage(IntPtr hwndOwner);
int GoFullScreen(bool fFullscreen);
int RenderFullScreen(ref TimedLevel pLevels);
}
[ComVisible(true)]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[Guid("695386EC-AA3C-4618-A5E1-DD9A8B987632")]
public interface IWmpEffects2 : IWmpEffects
{
int SetCore(IntPtr pPlayer);
int Create(IntPtr hwndParent);
int Destroy();
int NotifyNewMedia(IntPtr pMedia);
int OnWindowMessage(int Msg, int WParam, int LParam, ref int plResultParam);
int RenderWindowed(ref TimedLevel pData, bool fRequiredRender);
}
[ComVisible(true)]
[StructLayout(LayoutKind.Sequential)]
public struct Data
{
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 0x400)]
public byte[] Data0;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 0x400)]
public byte[] Data1;
}
[ComVisible(true)]
public enum PlayerState
{
Stop_State,
Pause_State,
Play_State
}
[ComVisible(true)]
[StructLayout(LayoutKind.Sequential)]
public struct TimedLevel
{
public Data Frequency;
public Data Waveform;
public PlayerState State;
public long TimeStamp;
}
[ComVisible(true)]
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int Left;
public int Top;
public int Right;
public int Bottom;
}
}
实现接口的类的代码如下所示
The code for the class implementing the interfaces is as follows
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using WmpTestPlugin;
using System.IO;
using System.Windows.Forms;
[ComVisible(true)]
[Guid("C476FF24-5E5C-419d-9110-05EC2EED8511")]
//[ProgId("WmpTestPlugin.WmpTest")]
[ClassInterface(ClassInterfaceType.None)]
public class TestPlugin : IWmpEffects2
{
[DllImport("user32.dll", EntryPoint = "GetClientRect")]
private static extern bool getClientRect(IntPtr windowHandle, ref IntPtr rectangle);
private const int EFFECT_CANGOFULLSCREEN = 1;
private const int EFFECT_HASPROPERTYPAGE = 2;
private const int S_OK = 0;
private const int S_FALSE = 1;
private const int E_ABORT = unchecked((int)0x80004004);
private const int E_ACCESSDENIED = unchecked((int)0x80070005);
private const int E_FAIL = unchecked((int)0x80004005);
private const int E_HANDLE = unchecked((int)0x80070006);
private const int E_INVALIDARG = unchecked((int)0x80070057);
private const int E_NOINTERFACE = unchecked((int)0x80004002);
private const int E_NOTIMPL = unchecked((int)0x80004001);
private const int E_OUTOFMEMORY = unchecked((int)0x8007000E);
private const int E_POINTER = unchecked((int)0x80004003);
private const int E_UNEXPECTED = unchecked((int)0x8000FFFF);
public TestPlugin()
{
_parentHwnd = IntPtr.Zero;
_preset = 0;
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : Construct{1}", DateTime.Now.ToString(), Environment.NewLine));
}
~TestPlugin()
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : Deconstruct{1}", DateTime.Now.ToString(), Environment.NewLine));
}
#region IWmpEffects2 Members
/// <summary>
/// Set WMP core interface
/// </summary>
/// <param name="pPlayer"></param>
/// <returns></returns>
public int SetCore(IntPtr pPlayer)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : SetCore{1}", DateTime.Now.ToString(), Environment.NewLine));
// release any existing WMP core interfaces
//ReleaseCore();
if (pPlayer == IntPtr.Zero)
return S_OK;
_playerCore = pPlayer;
//connect up any events
return S_OK;
}
/// <summary>
/// Invoked when the visualization should be initialized.
///
/// If hwndParent != NULL, RenderWindowed() will be called and the visualization
/// should draw into the window specified by hwndParent. This will be the
/// behavior when the visualization is hosted in a window.
///
/// If hwndParent == NULL, Render() will be called and the visualization
/// should draw into the DC passed to Render(). This will be the behavior when
/// the visualization is hosted windowless (like in a skin for example).
/// </summary>
/// <param name="hwndParent"></param>
/// <returns></returns>
public int Create(IntPtr hwndParent)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : Create{1}", DateTime.Now.ToString(), Environment.NewLine));
_parentHwnd = hwndParent;
return S_OK;
}
/// <summary>
/// Invoked when the visualization should be released.
/// Any resources allocated for rendering should be released.
/// </summary>
/// <returns></returns>
public int Destroy()
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : Destroy{1}", DateTime.Now.ToString(), Environment.NewLine));
_parentHwnd = IntPtr.Zero;
return S_OK;
}
/// <summary>
/// Invoked when a new media stream begins playing.
/// The visualization can inspect this object for properties (like name or artist)
/// that might be interesting for visualization.
/// </summary>
/// <param name="pMedia"></param>
/// <returns></returns>
public int NotifyNewMedia(IntPtr pMedia)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : NotifyNewMedia{1}", DateTime.Now.ToString(), Environment.NewLine));
return S_OK;
}
/// <summary>
/// Window messages sent to the parent window.
/// </summary>
/// <param name="Msg"></param>
/// <param name="WParam"></param>
/// <param name="LParam"></param>
/// <param name="plResultParam"></param>
/// <returns></returns>
public int OnWindowMessage(int Msg, int WParam, int LParam, ref int plResultParam)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : OnWindowMessage{1}", DateTime.Now.ToString(), Environment.NewLine));
// return S_OK only if the plugin has handled the window message
// return S_FALSE to let the defWindowProc handle the message
//if (_parentHwnd == IntPtr.Zero)
//m_NonWindowedRenderer.OnWindowMessage(&m_RenderContext, msg, WParam, LParam, plResultParam);
//else
// m_WindowedRenderer.OnWindowMessage(&m_RenderContext, msg, WParam, LParam, plResultParam);
return S_FALSE;
}
/// <summary>
/// Called when an effect should render itself to the screen.
/// The fRequiredRender flag specifies if an update is required, otherwise the
/// update is optional. This allows visualizations that are fairly static (for example,
/// album art visualizations) to only render when the parent window requires it,
/// instead of n times a second for dynamic visualizations.
/// </summary>
/// <param name="pData"></param>
/// <param name="fRequiredRender"></param>
/// <returns></returns>
public int RenderWindowed(ref TimedLevel pData, bool fRequiredRender)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : RenderWindowed{1}", DateTime.Now.ToString(), Environment.NewLine));
//windowed
// NULL parent window should not happen
if (_parentHwnd == IntPtr.Zero)
return E_UNEXPECTED;
//RECT rect = new RECT();
//TestPlugin.getClientRect(_parentHwnd, ref rect);
//do render//
return S_OK;
}
#endregion
#region IWmpEffects Members
/// <summary>
/// Called when an effect should render itself to the screen.
/// </summary>
/// <param name="pLevels"></param>
/// <param name="Hdc"></param>
/// <param name="pRC"></param>
/// <returns></returns>
public int Render(ref TimedLevel pLevels, IntPtr Hdc, ref RECT pRC)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : Render{1}", DateTime.Now.ToString(), Environment.NewLine));
//not windowed
//do render
return S_OK;
}
/// <summary>
/// Everytime new media is loaded, this method is called to pass the
/// number of channels (mono/stereo), the sample rate of the media, and the
/// title of the media
/// </summary>
/// <param name="lChannelCount"></param>
/// <param name="lSampleRate"></param>
/// <param name="bstrTitle"></param>
/// <returns></returns>
public int MediaInfo(int lChannelCount, int lSampleRate, string bstrTitle)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : MediaInfo{1}", DateTime.Now.ToString(), Environment.NewLine));
return S_OK;
}
/// <summary>
/// Returns the capabilities of this effect. Flags that can be returned are:
/// EFFECT_CANGOFULLSCREEN -- effect supports full-screen rendering
/// EFFECT_HASPROPERTYPAGE -- effect supports a property page
/// </summary>
/// <param name="pdwCapabilities"></param>
/// <returns></returns>
public int GetCapabilities(ref int pdwCapabilities)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : GetCapabilities{1}", DateTime.Now.ToString(), Environment.NewLine));
//no capabilities
pdwCapabilities = EFFECT_HASPROPERTYPAGE;
return S_OK;
}
/// <summary>
/// Invoked when a host wants to obtain the title of the effect
/// </summary>
/// <param name="bstrTitle"></param>
/// <returns></returns>
public int GetTitle(ref string bstrTitle)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : GetTitle{1}", DateTime.Now.ToString(), Environment.NewLine));
bstrTitle = "Test Wmp C# Plugin";
return S_OK;
}
/// <summary>
/// Invoked when a host wants to obtain the title of the given preset
/// </summary>
/// <param name="nPreset"></param>
/// <param name="bstrPresetTitle"></param>
/// <returns></returns>
public int GetPresetTitle(int nPreset, ref string bstrPresetTitle)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : GetPresetTitle{1}", DateTime.Now.ToString(), Environment.NewLine));
//bstrPresetTitle = "Default";
return S_OK;
}
/// <summary>
/// Invoked when a host wants to obtain the number of supported presets
/// </summary>
/// <param name="count"></param>
/// <returns></returns>
public int GetPresetCount(ref int count)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : GetPresetCount{1}", DateTime.Now.ToString(), Environment.NewLine));
count = 1;
return S_OK;
}
/// <summary>
/// Invoked when a host wants to obtain the index of the current preset
/// </summary>
/// <param name="currentpreset"></param>
/// <returns></returns>
public int SetCurrentPreset(int currentpreset)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : SetCurrentPreset{1}", DateTime.Now.ToString(), Environment.NewLine));
_preset = currentpreset;
return S_OK;
}
/// <summary>
/// Invoked when a host wants to obtain the index of the current preset
/// </summary>
/// <param name="currentpreset"></param>
/// <returns></returns>
public int GetCurrentPreset(ref int currentpreset)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : GetCurrentPreset{1}", DateTime.Now.ToString(), Environment.NewLine));
currentpreset = _preset;
return S_OK;
}
/// <summary>
/// Invoked when a host wants to display the property page for the effect
/// </summary>
/// <param name="hwndOwner"></param>
/// <returns></returns>
public int DisplayPropertyPage(IntPtr hwndOwner)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : DisplayPropertyPage, Owner={1}{2}", DateTime.Now.ToString(), hwndOwner.ToString(), Environment.NewLine));
MessageBox.Show("Hello Me!");
return S_OK;
}
public int GoFullScreen(bool fFullscreen)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : GoFullScreen{1}", DateTime.Now.ToString(), Environment.NewLine));
return S_OK;
}
public int RenderFullScreen(ref TimedLevel pLevels)
{
File.AppendAllText("C:\\wmp.txt", string.Format("{0} : RenderFullScreen{1}", DateTime.Now.ToString(), Environment.NewLine));
return S_OK;
}
#endregion
private IntPtr _parentHwnd;
private int _preset;
private IntPtr _playerCore;
}
正如你可以看到我的代码是相当空，仅此而已比存根真的。我的调试简单，但做这项工作。
As you can see my code is pretty empty, nothing more than stubs really. My debugging is simple but does the job.
一旦这与它可以注册一个强名称编译：
Once this is compiled with a strong name it can be registered with:
regasm assemblyname.dll / TLB
regasm assemblyname.dll /tlb
随后回落在GAC中。
打开注册表编辑器并添加以下
产品介绍：
Open regedit and add the the following info:
在
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MediaPlayer\ Objects\Effects
新的密钥： WmpTestPlugin
在新的键添加一个新字符串
值：名称：CLASSID价值：
{C476FF24-5E5C-419d-9110-05EC2EED8511}
Under the new key add a new string value: Name: classid Value: {C476FF24-5E5C-419d-9110-05EC2EED8511}
因此，我们必须建立一个符合接口插件，它注册在GAC告诉媒体播放器，它的存在。
So we have built a plugin that conforms to the interfaces, registered it in the GAC and told media player it's there.
如果您打开媒体播放器在可视化空间会出现一个菜单，并单击鼠标右键。在该菜单将是我们新的插件。当你向下移动鼠标到新的项目WMP会调用 GetPresetCount 的插件（这将记录到文件）。然后，WMP应该调用 GetPresetTitle ，但它从来不会对我来说。
If you open media player and right-click on the visualization space a menu will appear. In that menu will be our new plugin. When you move your mouse down to the new item WMP will call GetPresetCount on the plugin (this will log to the file). Then WMP is supposed to call GetPresetTitle but it NEVER does for me.
如果从菜单栏中打开tools\options并选择插件选项卡您可以选择新的插件。如果您单击属性WMP会叫获得性能和 DisplayPropertyPage 和消息从插件对话框将会出现。 WMP然后崩溃。在C ++版本的的FinalConstruct（）被称为 CComCoClass 接口上 - 我没有这个，不知道它是什么。我想这可能是较低的水平比我现在用的？
If you open tools\options from the menu bar and select the Plugins tab you can select the new plugin. If you click Properties WMP will call GetCapabilities then DisplayPropertyPage and a message box from the plugin will appear. WMP then crashes. In the C++ version FinalConstruct() is called on a CComCoClass interface - I don't have this and don't know what it is. I think it may be lower level than I am using??
我已经尝试了许多许多事情得到这个工作，包括改变方法声明。请能有人看它和帮助。我找遍了整个网络的解决方案，并没有发现什么。
I have tried many many things to get this to work including changing the method declarations. Please can someone look at it and help. I've looked all over the web for a solution and found nothing.
感谢您的阅读，
纳努克
Thanks for reading, Nanook
推荐答案
看一些Windows Shell中的互操作代码后，我发现，我应该一直在使用[ComImport]和接口不是[标记有ComVisible特性。为了使签名等于已注册的我用[PreserveSig。该接口的传承也需要通过重新声明父项基本接口提供一些帮助。
After looking at some Windows Shell interop code I discovered that I should have been using [ComImport] and NOT [ComVisible] for the interfaces. To make the signatures equal to that already registered I used [PreserveSig]. The interface inheritence also needed some help by redeclaring the base interface within the parent.
我希望这可以帮助别人。
I hope this helps someone.
下面是工人阶级
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
namespace WmpTestPlugin
{
[ComImport]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[Guid("695386EC-AA3C-4618-A5E1-DD9A8B987632")]
public interface IWmpEffects2 : IWmpEffects
{
[PreserveSig]
new int Render(ref TimedLevel pLevels, IntPtr Hdc, ref RECT pRC);
[PreserveSig]
new int MediaInfo(int lChannelCount, int lSampleRate, string bstrTitle);
[PreserveSig]
new int GetCapabilities(ref int pdwCapabilities);
[PreserveSig]
new int GetTitle(ref string bstrTitle);
[PreserveSig]
new int GetPresetTitle(int nPreset, ref string bstrPresetTitle);
[PreserveSig]
new int GetPresetCount(ref int count);
[PreserveSig]
new int SetCurrentPreset(int currentpreset);
[PreserveSig]
new int GetCurrentPreset(ref int currentpreset);
[PreserveSig]
new int DisplayPropertyPage(IntPtr hwndOwner);
[PreserveSig]
new int GoFullScreen(bool fFullscreen);
[PreserveSig]
new int RenderFullScreen(ref TimedLevel pLevels);
[PreserveSig]
int SetCore(IntPtr pPlayer);
[PreserveSig]
int Create(IntPtr hwndParent);
[PreserveSig]
int Destroy();
[PreserveSig]
int NotifyNewMedia(IntPtr pMedia);
[PreserveSig]
int OnWindowMessage(int Msg, int WParam, int LParam, ref int plResultParam);
[PreserveSig]
int RenderWindowed(ref TimedLevel pData, bool fRequiredRender);
}
[ComImport]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[Guid("D3984C13-C3CB-48e2-8BE5-5168340B4F35")]
public interface IWmpEffects
{
[PreserveSig]
int Render(ref TimedLevel pLevels, IntPtr Hdc, ref RECT pRC);
[PreserveSig]
int MediaInfo(int lChannelCount, int lSampleRate, string bstrTitle);
[PreserveSig]
int GetCapabilities(ref int pdwCapabilities);
[PreserveSig]
int GetTitle(ref string bstrTitle);
[PreserveSig]
int GetPresetTitle(int nPreset, ref string bstrPresetTitle);
[PreserveSig]
int GetPresetCount(ref int count);
[PreserveSig]
int SetCurrentPreset(int currentpreset);
[PreserveSig]
int GetCurrentPreset(ref int currentpreset);
[PreserveSig]
int DisplayPropertyPage(IntPtr hwndOwner);
[PreserveSig]
int GoFullScreen(bool fFullscreen);
[PreserveSig]
int RenderFullScreen(ref TimedLevel pLevels);
}
//[ComVisible(true)]
[StructLayout(LayoutKind.Sequential)]
public struct Data
{
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 0x400)]
public byte[] Data0;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 0x400)]
public byte[] Data1;
}
//[ComVisible(true)]
public enum PlayerState
{
Stop_State,
Pause_State,
Play_State
}
//[ComVisible(true)]
[StructLayout(LayoutKind.Sequential)]
public struct TimedLevel
{
public Data Frequency;
public Data Waveform;
public PlayerState State;
public long TimeStamp;
}
//[ComVisible(true)]
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int Left;
public int Top;
public int Right;
public int Bottom;
public int Width { get { return this.Right - this.Left; } }
public int Height { get { return this.Bottom - this.Top; } }
}
}
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