最近想通过DirectShow获取摄像头所支持分辨率，但发现基本都是C++的代码，虽然俺对C++也很喜欢，但现在是要在C#上实现呀~好吧，只能自己从C++转为C#了，其中有些难点就是结构体与接口的命名规则有了一些小小的改变。

    using System;
    using System.Collections.Generic;
    using System.Drawing;
    using System.Runtime.InteropServices;
    using DirectShowLib;

        ///
        /// 获取摄像头所支持的分辨率
        ///
        /// 华仔103
        public void GetCaptureSupportSize(ICaptureGraphBuilder2 capGraph, IBaseFilter captureFilter)
        {
            object streamConfig;

            // 获取配置接口
            int hr = capGraph.FindInterface(PinCategory.Capture,
                                            MediaType.Video,
                                            captureFilter,
                                            typeof(IAMStreamConfig).GUID,
                                            out streamConfig);

            DsError.ThrowExceptionForHR(hr);

            var videoStreamConfig = streamConfig as IAMStreamConfig;

           
            if (videoStreamConfig == null)
            {
                throw new Exception("Failed to get IAMStreamConfig");
            }

            int iCount;//好吧，我承认这是C++的变量命名方法，可我就是不想改~
            int iSize;
            VideoStreamConfigCaps vscc = new VideoStreamConfigCaps();
            hr = videoStreamConfig.GetNumberOfCapabilities(out iCount, out iSize);
            DsError.ThrowExceptionForHR(hr);

            // 判断为正确获取的信息
            if (Marshal.SizeOf(vscc) == iSize)
            {
                for (int i = 0; i < iCount; ++i)
                {
                    // 分配非托管内存
                    IntPtr pVscc = Marshal.AllocCoTaskMem(Marshal.SizeOf(vscc));
                    AMMediaType amMediaType;

                    hr = videoStreamConfig.GetStreamCaps(i, out amMediaType, pVscc);
                    DsError.ThrowExceptionForHR(hr);
                    // 如果为视频信息
                    if (amMediaType.majorType == MediaType.Video &&
                        amMediaType.formatType == FormatType.VideoInfo)
                    {
                        Marshal.StructureToPtr(vscc, pVscc, false);

                       
                        var videoInfoHeader = new VideoInfoHeader();
                        Marshal.PtrToStructure(amMediaType.formatPtr, videoInfoHeader);

                       
                        // 获取摄像头所支持的分辨率
                        int width = videoInfoHeader.BmiHeader.Width;
                        int height = videoInfoHeader.BmiHeader.Height;
                    }
                    // 释放非托管内存
                    Marshal.FreeCoTaskMem(pVscc);
                    DsUtils.FreeAMMediaType(amMediaType);
                }
            }
            return;
        }