C# 实现PPT、Word、Excel文件转为图片

背景：因前有OfficeOnline的搭建，所以搭建完之后领导又提出要求啦，说：小xu，你……你把这文件的缩略图给我整出来吧。经过我历时久远的研究（这个问题跨了个年，随着2020疫情的发展，还过了两个月，放了个大长假）。但终，解决了，心头大患也。

 

嗯~巴适~

好啦，正戏正儿八经开始了！现在这里有两种解决方案，且听我细细说来~

 

使用普通方法截取文件图片

优点：① 所有文件都可以被截取；

缺点：① 除PPT外截取的都是文件的图标；

  　　  ② 截取图片比较模糊；

 　　   ③ 截取图片有黑边；

如下图：

代码

    [Flags]
    public enum ThumbnailOptions
    {
        None = 0x00,
        BiggerSizeOk = 0x01,
        InMemoryOnly = 0x02,
        IconOnly = 0x04,
        ThumbnailOnly = 0x08,
        InCacheOnly = 0x10,
    }

    public class WindowsThumbnailProvider
    {
        private const string IShellItem2Guid = "7E9FB0D3-919F-4307-AB2E-9B1860310C93";

        [DllImport("shell32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        internal static extern int SHCreateItemFromParsingName(
            [MarshalAs(UnmanagedType.LPWStr)] string path,
            // The following parameter is not used - binding context.
            IntPtr pbc,
            ref Guid riid,
            [MarshalAs(UnmanagedType.Interface)] out IShellItem shellItem);

        [DllImport("gdi32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool DeleteObject(IntPtr hObject);

        [ComImport]
        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        [Guid("43826d1e-e718-42ee-bc55-a1e261c37bfe")]
        internal interface IShellItem
        {
            void BindToHandler(IntPtr pbc,
                [MarshalAs(UnmanagedType.LPStruct)]Guid bhid,
                [MarshalAs(UnmanagedType.LPStruct)]Guid riid,
                out IntPtr ppv);

            void GetParent(out IShellItem ppsi);
            void GetDisplayName(SIGDN sigdnName, out IntPtr ppszName);
            void GetAttributes(uint sfgaoMask, out uint psfgaoAttribs);
            void Compare(IShellItem psi, uint hint, out int piOrder);
        };

        internal enum SIGDN : uint
        {
            NORMALDISPLAY = 0,
            PARENTRELATIVEPARSING = 0x80018001,
            PARENTRELATIVEFORADDRESSBAR = 0x8001c001,
            DESKTOPABSOLUTEPARSING = 0x80028000,
            PARENTRELATIVEEDITING = 0x80031001,
            DESKTOPABSOLUTEEDITING = 0x8004c000,
            FILESYSPATH = 0x80058000,
            URL = 0x80068000
        }

        internal enum HResult
        {
            Ok = 0x0000,
            False = 0x0001,
            InvalidArguments = unchecked((int)0x80070057),
            OutOfMemory = unchecked((int)0x8007000E),
            NoInterface = unchecked((int)0x80004002),
            Fail = unchecked((int)0x80004005),
            ElementNotFound = unchecked((int)0x80070490),
            TypeElementNotFound = unchecked((int)0x8002802B),
            NoObject = unchecked((int)0x800401E5),
            Win32ErrorCanceled = 1223,
            Canceled = unchecked((int)0x800704C7),
            ResourceInUse = unchecked((int)0x800700AA),
            AccessDenied = unchecked((int)0x80030005)
        }

        [ComImportAttribute()]
        [GuidAttribute("bcc18b79-ba16-442f-80c4-8a59c30c463b")]
        [InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
        internal interface IShellItemImageFactory
        {
            [PreserveSig]
            HResult GetImage(
            [In, MarshalAs(UnmanagedType.Struct)] NativeSize size,
            [In] ThumbnailOptions flags,
            [Out] out IntPtr phbm);
        }

        [StructLayout(LayoutKind.Sequential)]
        internal struct NativeSize
        {
            private int width;
            private int height;

            public int Width { set { width = value; } }
            public int Height { set { height = value; } }
        };

        [StructLayout(LayoutKind.Sequential)]
        public struct RGBQUAD
        {
            public byte rgbBlue;
            public byte rgbGreen;
            public byte rgbRed;
            public byte rgbReserved;
        }

        /// <summary>
        /// 获取缩略图
        /// </summary>
        /// <param name="filePath">文件所在绝对路径</param>
        /// <param name="width">图片宽</param>
        /// <param name="height">图片高</param>
        /// <param name="options"></param>
        public static void GetThumbnail(string filePath, string imgFullPath, int width, int height, ThumbnailOptions options)
        {
            IntPtr hBitmap = GetHBitmap(Path.GetFullPath(filePath), width, height, options);
            try
            {
                SaveBitmap(hBitmap, imgFullPath);
            }
            catch
            {
                throw;
            }
            finally
            {
                DeleteObject(hBitmap);
            }
        }

        /// <summary>
        /// 将Bitmap转换成图片，并返回缩略图相对路径
        /// </summary>
        /// <param name="hBitmap"></param>
        /// <param name="fileName">文件名称</param>
        /// <returns></returns>
        public static void SaveBitmap(IntPtr hBitmap, string imgFullPath)
        {
            try
            {
                Bitmap bmp = GetBitmapFromHBitmap(hBitmap);
                bmp.Save(imgFullPath, ImageFormat.Jpeg);
            }
            catch (IOException ex)
            {
                throw ex;
            }
        }

        /// <summary>
        /// 将HBitmap转换成Bitmap
        /// </summary>
        /// <param name="nativeHBitmap"></param>
        /// <returns></returns>
        public static Bitmap GetBitmapFromHBitmap(IntPtr nativeHBitmap)
        {
            Bitmap bmp = Bitmap.FromHbitmap(nativeHBitmap);

            if (Bitmap.GetPixelFormatSize(bmp.PixelFormat) < 32)
                return bmp;

            return CreateAlphaBitmap(bmp, PixelFormat.Format32bppArgb);
        }

        /// <summary>
        /// 创建图片
        /// </summary>
        /// <param name="srcBitmap"></param>
        /// <param name="targetPixelFormat"></param>
        /// <returns></returns>
        public static Bitmap CreateAlphaBitmap(Bitmap srcBitmap, PixelFormat targetPixelFormat)
        {
            Bitmap result = new Bitmap(srcBitmap.Width, srcBitmap.Height, targetPixelFormat);

            Rectangle bmpBounds = new Rectangle(0, 0, srcBitmap.Width, srcBitmap.Height);

            BitmapData srcData = srcBitmap.LockBits(bmpBounds, ImageLockMode.ReadOnly, srcBitmap.PixelFormat);

            bool isAlplaBitmap = false;

            try
            {
                for (int y = 0; y <= srcData.Height - 1; y++)
                {
                    for (int x = 0; x <= srcData.Width - 1; x++)
                    {
                        Color pixelColor = Color.FromArgb(
                            Marshal.ReadInt32(srcData.Scan0, (srcData.Stride * y) + (4 * x)));

                        if (pixelColor.A > 0 & pixelColor.A < 255)
                        {
                            isAlplaBitmap = true;
                        }

                        result.SetPixel(x, y, pixelColor);
                    }
                }
            }
            finally
            {
                srcBitmap.UnlockBits(srcData);
            }

            if (isAlplaBitmap)
            {
                return result;
            }
            else
            {
                return srcBitmap;
            }
        }

        /// <summary>
        /// GetHBitmap
        /// </summary>
        /// <param name="fileName"></param>
        /// <param name="width"></param>
        /// <param name="height"></param>
        /// <param name="options"></param>
        /// <returns></returns>
        private static IntPtr GetHBitmap(string fileName, int width, int height, ThumbnailOptions options)
        {
            IShellItem nativeShellItem;
            Guid shellItem2Guid = new Guid(IShellItem2Guid);
            int retCode = SHCreateItemFromParsingName(fileName, IntPtr.Zero, ref shellItem2Guid, out nativeShellItem);

            if (retCode != 0)
                throw Marshal.GetExceptionForHR(retCode);

            NativeSize nativeSize = new NativeSize();
            nativeSize.Width = width;
            nativeSize.Height = height;

            IntPtr hBitmap;
            HResult hr = ((IShellItemImageFactory)nativeShellItem).GetImage(nativeSize, options, out hBitmap);

            Marshal.ReleaseComObject(nativeShellItem);

            if (hr == HResult.Ok) return hBitmap;

            throw Marshal.GetExceptionForHR((int)hr);
        }
    }

如何使用

//string filePath = "E:\File\我就是很开心.txt";//文件所在位置
//string filePath = "E:\File\我有点不开心.xlsx";//文件所在位置
//string filePath = "E:\File\你看起来很好吃.docx";//文件所在位置
string filePath = "E:\File\项目测试使用文件.pptx";//文件所在位置

//自定义图片路径
string imgName = Path.GetFileName(filePath).Split('.')[0];
string direcName = Path.GetDirectoryName(filePath);
string imgFullPath = $"{direcName}\{imgName}.jpg";//重组，获取图片存放位置

int pic_size = 1000;
WindowsThumbnailProvider.GetThumbnail(filePath, imgFullPath, pic_size, pic_size, ThumbnailOptions.None);
  

使用Aspose截取文件图片

注意：Aspose自身可以截取所有文件，但我这里设置的目前只能截取rar、ppt、excel、word这四种格式，其他格式就会报错。你如果需要更多的文件格式截图，就再进行研究就阔以。该dll中的方法可以截取多张图片，不一定就是文件首页。笔芯~

 

 

 

去水印

如果没有破解码，直接使用aspose，打印出来的照片就会有水印。如下图：

 所以你需要在App.config中，添加一个节点，如下：

（注：web项目对应的是web.config;控制台项目对应的是app.config,不过下面节点在两种文件里面都通用)

<add key="AsposeKey" value="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" />

注：使用此码是对aspose各个dll的版本有要求的，需要在2015年12月30日之前的版本，才可以使用。所以你可以去nuget官网（https://www.nuget.org/packages?q=Aspose.Words）查找相应日期对应的版本。如果你懒，你懒，懒……，不用担心，我给你找好了。

名称	版本	日期
Aspose.Words	15.12.0	2015/12/26
Aspose.Excel	8.6.3	2015/12/23
Aspose.Slides	15.10.0.0	2015/12/10
Aspose.Pdf	11.1.1.0	2015/12/30

代码

详见下面的链接中的解决方案吧，不想复制了，实在是太多啦。

如何使用

//string filePath = "E:\File\我就是很开心.txt";//文件所在位置
//string filePath = "E:\File\我有点不开心.xlsx";//文件所在位置
//string filePath = "E:\File\你看起来很好吃.docx";//文件所在位置
string filePath = "E:\File\项目测试使用文件.pptx";//文件所在位置

//自定义图片路径
string imgName = Path.GetFileName(filePath).Split('.')[0];
string direcName = Path.GetDirectoryName(filePath);
string imgFullPath = $"{direcName}\{imgName}.jpg";//重组，获取图片存放位置

string extendName = Path.GetExtension(filePath);

//这里运用的是简单工厂模式
ImageConverterFactory factory = new ImageConverterFactory();
var imageConvert = factory.CreateImageConverter(extendName);
imageConvert.ConvertToImage(filePath, imgFullPath);

代码下载

两种方法在同一个解决方案里

 百度云盘：链接：https://pan.baidu.com/s/10edFyh1W_6zYjcTVmXFGEQ  提取码：1l4t 

感谢大佬的热心分享：https://www.cnblogs.com/zhuweisky/p/4774803.html

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