C# Windows Forms 中的 WIA 扫描仪

• 下载扫描仪应用程序（无 EXE）
• 下载扫描仪应用程序
• 下载 Interop.WIA.dll
• 下载 Interop.WIA.dll（无 EXE）

引言

该项目用于演示如何使用 WIA Windows 图像采集 支持的扫描仪。使用此项目，我们可以从扫描仪扫描应用程序，并自动保存到特定位置。

背景

通过此项目，我们可以学习如何通过 C# 访问扫描仪。对于此项目，我们需要两样东西

1. WIA DLL
2. WIA 类

WIA dll 可以在我的资源文件中找到。

您可以添加此 WIA 类，无需进行任何更改。

class WIAScanner
    {
        const string wiaFormatBMP = "{B96B3CAB-0728-11D3-9D7B-0000F81EF32E}";
        class WIA_DPS_DOCUMENT_HANDLING_SELECT
        {
            public const uint FEEDER = 0x00000001;
            public const uint FLATBED = 0x00000002;
        }
        class WIA_DPS_DOCUMENT_HANDLING_STATUS
        {
            public const uint FEED_READY = 0x00000001;
        }
        class WIA_PROPERTIES
        { 
            public const uint WIA_RESERVED_FOR_NEW_PROPS = 1024;
            public const uint WIA_DIP_FIRST = 2;
            public const uint WIA_DPA_FIRST = WIA_DIP_FIRST + WIA_RESERVED_FOR_NEW_PROPS;
            public const uint WIA_DPC_FIRST = WIA_DPA_FIRST + WIA_RESERVED_FOR_NEW_PROPS;
            //
            // Scanner only device properties (DPS)
            //
            public const uint WIA_DPS_FIRST = WIA_DPC_FIRST + WIA_RESERVED_FOR_NEW_PROPS;
            public const uint WIA_DPS_DOCUMENT_HANDLING_STATUS = WIA_DPS_FIRST + 13;
            public const uint WIA_DPS_DOCUMENT_HANDLING_SELECT = WIA_DPS_FIRST + 14;
        }
         /// <summary>
        /// Use scanner to scan an image (with user selecting the scanner from a dialog).
        /// </summary>
        /// <returns>Scanned images.</returns>
        public static List<Image> Scan()
        {
            WIA.ICommonDialog dialog = new WIA.CommonDialog();
            WIA.Device device = dialog.ShowSelectDevice
                (WIA.WiaDeviceType.UnspecifiedDeviceType, true, false);
            if (device != null)
            {
                return Scan(device.DeviceID);
            }
            else
            {
                throw new Exception("You must select a device for scanning.");
            }
        }
        /// <summary>
        /// Use scanner to scan an image (scanner is selected by its unique id).
        /// </summary>
        /// <param name="scannerName"></param>
        /// <returns>Scanned images.</returns>
      public static List<Image> Scan(string scannerId)
        {
            List<Image> images = new List<Image>();
            bool hasMorePages = true;
            while (hasMorePages)
            {
                // select the correct scanner using the provided scannerId parameter
                WIA.DeviceManager manager = new WIA.DeviceManager();
                WIA.Device device = null;
                foreach (WIA.DeviceInfo info in manager.DeviceInfos)
                {
                    if (info.DeviceID == scannerId)
                    {
                        // connect to scanner
                        device = info.Connect();
                        break;
                    }
                }
                // device was not found
                if (device == null)
                {
                    // enumerate available devices
                    string availableDevices = "";
                    foreach (WIA.DeviceInfo info in manager.DeviceInfos)
                    {
                        availableDevices += info.DeviceID + "\n";
                    }
                    // show error with available devices
                    throw new Exception("The device with provided ID could not be found. 
                    Available Devices:\n" + availableDevices);
                }
                WIA.Item item = device.Items[1] as WIA.Item;
                try
                {
                    // scan image
                    WIA.ICommonDialog wiaCommonDialog = new WIA.CommonDialog();
        WIA.ImageFile image = (WIA.ImageFile)wiaCommonDialog.ShowTransfer(item,wiaFormatBMP                                                                           , false);
                      // save to temp file
                    string fileName = Path.GetTempFileName();
                    File.Delete(fileName);
                    image.SaveFile(fileName);
                    image = null;
                    // add file to output list
                    images.Add(Image.FromFile(fileName));
                }
                catch (Exception exc)
                {
                    throw exc;
                }
                finally
                {
                    item = null;
                    //determine if there are any more pages waiting
                    WIA.Property documentHandlingSelect = null;
                    WIA.Property documentHandlingStatus = null;
                    foreach (WIA.Property prop in device.Properties)
                    {
                    if (prop.PropertyID == WIA_PROPERTIES.WIA_DPS_DOCUMENT_HANDLING_SELECT)
                            documentHandlingSelect = prop;
                    if (prop.PropertyID == WIA_PROPERTIES.WIA_DPS_DOCUMENT_HANDLING_STATUS)
                            documentHandlingStatus = prop;
                    }
                    // assume there are no more pages
                    hasMorePages = false;
                    // may not exist on flatbed scanner but required for feeder
                    if (documentHandlingSelect != null)
                    {
                        // check for document feeder
                        if ((Convert.ToUInt32(documentHandlingSelect.get_Value()) & 
                        WIA_DPS_DOCUMENT_HANDLING_SELECT.FEEDER) != 0)
                        {
                            hasMorePages = ((Convert.ToUInt32(documentHandlingStatus.get_Value()) & 
                            WIA_DPS_DOCUMENT_HANDLING_STATUS.FEED_READY) != 0);
                        }
                    }
                }
            }
            return images;
        }
        /// <summary>
        /// Gets the list of available WIA devices.
        /// </summary>
        /// <returns></returns>
        public static List<string> GetDevices()
        {
            List<string> devices = new List<string>();
            WIA.DeviceManager manager = new WIA.DeviceManager();
            foreach (WIA.DeviceInfo info in manager.DeviceInfos)
            {
                devices.Add(info.DeviceID);
            }
            return devices;
        }
    }

Using the Code

我创建了一个用户界面设计如下

这里“扫描”按钮用于触发事件以扫描放置在扫描仪中的对象。我使用了面板控件来显示扫描的图像。

扫描放置在扫描仪设备中的对象后，UI 将如下所示

在这里，我将扫描的图像保存到特定位置，格式为 yyyy-MM-dd HHmmss。

关注点

通过此项目，我们可以学习如何访问本地设备，如打印机、扫描仪和摄像头。