这篇文章主要讲解了“C#如何使用com获取Windows摄像头列表”,文中的讲解内容简单清晰,易于学习与理解,下面请大家跟着小编的思路慢慢深入,一起来研究和学习“C#如何使用com获取Windows摄像头列表”吧!
我们使用directshow获取视频设备列表,由于com的跨语言特性,完全可以直接在C#中调用,而不用通过C++封装一层dll给C#使用。我们首先定义需要的com对象接口。
static readonly Guid SystemDeviceEnum = new Guid(0x62BE5D10, 0x60EB, 0x11D0, 0xBD, 0x3B, 0x00, 0xA0, 0xC9, 0x11, 0xCE, 0x86); static readonly Guid VideoInputDevice = new Guid(0x860BB310, 0x5D01, 0x11D0, 0xBD, 0x3B, 0x00, 0xA0, 0xC9, 0x11, 0xCE, 0x86); [Flags] enum CDef { None = 0x0, ClassDefault = 0x1, BypassClassManager = 0x2, ClassLegacy = 0x4, MeritAboveDoNotUse = 0x8, DevmonCMGRDevice = 0x10, DevmonDMO = 0x20, DevmonPNPDevice = 0x40, DevmonFilter = 0x80, DevmonSelectiveMask = 0xF0 } [ComImport] [SuppressUnmanagedCodeSecurity] [Guid("3127CA40-446E-11CE-8135-00AA004BB851")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] interface IErrorLog { [PreserveSig] int AddError([In][MarshalAs(UnmanagedType.LPWStr)] string pszPropName, [In] System.Runtime.InteropServices.ComTypes.EXCEPINFO pExcepInfo); } [ComImport] [Localizable(false)] [SuppressUnmanagedCodeSecurity] [Guid("55272A00-42CB-11CE-8135-00AA004BB851")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] interface IPropertyBag { [PreserveSig] int Read([In][MarshalAs(UnmanagedType.LPWStr)] string pszPropName, [MarshalAs(UnmanagedType.Struct)] out object pVar, [In] IErrorLog pErrorLog); [PreserveSig] int Write([In][MarshalAs(UnmanagedType.LPWStr)] string pszPropName, [In][MarshalAs(UnmanagedType.Struct)] ref object pVar); } [ComImport] [SuppressUnmanagedCodeSecurity] [Guid("29840822-5B84-11D0-BD3B-00A0C911CE86")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] interface ICreateDevEnum { [PreserveSig] int CreateClassEnumerator([In][MarshalAs(UnmanagedType.LPStruct)] Guid pType, out IEnumMoniker ppEnumMoniker, [In] CDef dwFlags); }
与directshow流程一样,调用com枚举设备即可,本文只展示获取设备名称(FriendlyName),获取其他属性可以参照c++调用directshow的实现。
/// <summary> /// 枚举视频设备 /// </summary> public static IEnumerable<string> Devices { get { IMoniker[] monikers = new IMoniker[5]; var devEnum = Activator.CreateInstance(Type.GetTypeFromCLSID(SystemDeviceEnum)) as ICreateDevEnum; IEnumMoniker moniker; if (devEnum.CreateClassEnumerator(VideoInputDevice, out moniker, 0) == 0) { while (true) { int r = moniker.Next(1, monikers, IntPtr.Zero); if (r != 0 || monikers[0] == null) break; yield return GetName(monikers[0]); foreach (var i in monikers) { if(i!=null) Marshal.ReleaseComObject(i); } } Marshal.ReleaseComObject(moniker); } Marshal.ReleaseComObject(devEnum); } } /// <summary> /// 获取设备名称 /// </summary> /// <param name="moniker"></param> /// <returns></returns> static string GetName(IMoniker moniker) { IPropertyBag property; object value; object temp = null; try { Guid guid = typeof(IPropertyBag).GUID; moniker.BindToStorage(null, null, ref guid, out temp); property = temp as IPropertyBag; int hr = property.Read("FriendlyName", out value, null); Marshal.ThrowExceptionForHR(hr); return value as string; } catch (Exception) { return null; } finally { if (temp != null) { Marshal.ReleaseComObject(temp); } } }
using System; using System.Collections.Generic; using System.ComponentModel; using System.Runtime.InteropServices; using System.Runtime.InteropServices.ComTypes; using System.Security; namespace AC { public class EnumDevices { /// <summary> /// 枚举视频设备 /// </summary> public static IEnumerable<string> Devices { get { IMoniker[] monikers = new IMoniker[5]; var devEnum = Activator.CreateInstance(Type.GetTypeFromCLSID(SystemDeviceEnum)) as ICreateDevEnum; IEnumMoniker moniker; if (devEnum.CreateClassEnumerator(VideoInputDevice, out moniker, 0) == 0) { while (true) { int hr = moniker.Next(1, monikers, IntPtr.Zero); if (hr != 0 || monikers[0] == null) break; yield return GetName(monikers[0]); foreach (var i in monikers) { if(i!=null) Marshal.ReleaseComObject(i); } } Marshal.ReleaseComObject(moniker); } Marshal.ReleaseComObject(devEnum); } } /// <summary> /// 获取设备名称 /// </summary> /// <param name="moniker"></param> /// <returns></returns> static string GetName(IMoniker moniker) { IPropertyBag property; object value; object temp = null; try { Guid guid = typeof(IPropertyBag).GUID; moniker.BindToStorage(null, null, ref guid, out temp); property = temp as IPropertyBag; int hr = property.Read("FriendlyName", out value, null); Marshal.ThrowExceptionForHR(hr); return value as string; } catch (Exception) { return null; } finally { if (temp != null) { Marshal.ReleaseComObject(temp); } } } static readonly Guid SystemDeviceEnum = new Guid(0x62BE5D10, 0x60EB, 0x11D0, 0xBD, 0x3B, 0x00, 0xA0, 0xC9, 0x11, 0xCE, 0x86); static readonly Guid VideoInputDevice = new Guid(0x860BB310, 0x5D01, 0x11D0, 0xBD, 0x3B, 0x00, 0xA0, 0xC9, 0x11, 0xCE, 0x86); [Flags] enum CDef { None = 0x0, ClassDefault = 0x1, BypassClassManager = 0x2, ClassLegacy = 0x4, MeritAboveDoNotUse = 0x8, DevmonCMGRDevice = 0x10, DevmonDMO = 0x20, DevmonPNPDevice = 0x40, DevmonFilter = 0x80, DevmonSelectiveMask = 0xF0 } [ComImport] [SuppressUnmanagedCodeSecurity] [Guid("3127CA40-446E-11CE-8135-00AA004BB851")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] interface IErrorLog { [PreserveSig] int AddError([In][MarshalAs(UnmanagedType.LPWStr)] string pszPropName, [In] System.Runtime.InteropServices.ComTypes.EXCEPINFO pExcepInfo); } [ComImport] [Localizable(false)] [SuppressUnmanagedCodeSecurity] [Guid("55272A00-42CB-11CE-8135-00AA004BB851")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] interface IPropertyBag { [PreserveSig] int Read([In][MarshalAs(UnmanagedType.LPWStr)] string pszPropName, [MarshalAs(UnmanagedType.Struct)] out object pVar, [In] IErrorLog pErrorLog); [PreserveSig] int Write([In][MarshalAs(UnmanagedType.LPWStr)] string pszPropName, [In][MarshalAs(UnmanagedType.Struct)] ref object pVar); } [ComImport] [SuppressUnmanagedCodeSecurity] [Guid("29840822-5B84-11D0-BD3B-00A0C911CE86")] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] interface ICreateDevEnum { [PreserveSig] int CreateClassEnumerator([In][MarshalAs(UnmanagedType.LPStruct)] Guid pType, out IEnumMoniker ppEnumMoniker, [In] CDef dwFlags); } } }
.net 6.0代码示例如下
// See https://aka.ms/new-console-template for more information using AC; //枚举设备 foreach (var i in EnumDevices.Devices) { //打印设备名称 Console.WriteLine(i); }
效果:
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