PDFOffice_Windows_exe/PDF Office/ViewModels/Dialog/HomePageToolsDialogs/CreateFromScannerDialogsViewModel.cs

using NTwain;
using NTwain.Data;
using PDF_Master.Model;
using Prism.Commands;
using Prism.Mvvm;
using Prism.Services.Dialogs;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace PDF_Master.ViewModels.Dialog.HomePageToolsDialogs
{

    //扫描仪设备
    public class ScannerItem : BindableBase
    {
        public DataSource DataSourceItem { get; set; }
        public ScannerItem(DataSource dataSource)
        {
            DataSourceItem = dataSource;
            ScannerName = dataSource.Name;
        }
        public string ScannerName { get; set; }
    }

    public class CreateFromScannerDialogsViewModel : BindableBase, IDialogAware
    {

        private List<ScannerItem> _scanners = new List<ScannerItem>();
        public List<ScannerItem> Scanners
        {
            get { return _scanners; }
            set => SetProperty(ref _scanners, value);
        }
        //图片
        private ImageSource _img;
        public ImageSource Img
        {
            get { return _img; }
            set => SetProperty(ref _img, value);
        }

       //没有检测到扫描仪
        private bool _isEmptyScanner;
        public bool IsEmptyScanner
        {
            get { return _isEmptyScanner; }
            set => SetProperty(ref _isEmptyScanner, value);
        }

        //没有生成图片
        private bool isEmptyImg;
        public bool IsEmptyImg
        {
            get { return isEmptyImg; }
            set => SetProperty(ref isEmptyImg, value);
        }

        public string Title => "";
        //图片路径
        public string FilePath { get; private set; }
        private bool IsScanner = false;
        public event Action<IDialogResult> RequestClose;

        private TwainSession twain;


        public DelegateCommand CancelCommand { get; set; }
        public DelegateCommand CreateCommand { get; set; }
        public DelegateCommand<object> SelectedScannerCommand { get; set; }

        public CreateFromScannerDialogsViewModel()
        {
            CancelCommand = new DelegateCommand(cancel);
            CreateCommand = new DelegateCommand(createFile, CanExcuteCreateFile).ObservesProperty(() => Img);
            SelectedScannerCommand = new DelegateCommand<object>(SelectedScanner);

            SetupTwain();

            if (Scanners.Count > 0)
                IsEmptyScanner = false;
            else
                IsEmptyScanner = true;
        }

        //选择扫描仪
        private void SelectedScanner(object obj)
        {
            if(obj != null)
            {
                if (twain.State == 4)
                {
                    twain.CurrentSource.Close();
                }
                Img = null;
                OpenSaveScanner();
                var result = obj as ScannerItem;
                if (result.DataSourceItem.Open() != ReturnCode.Success)
                    MessageBox.Show("连接失败");
                else
                {
                    
                }
                Preview();
            }
            
        }

        //启动检测扫描仪
        private void SetupTwain()
        {
            var appId = TWIdentity.CreateFromAssembly(DataGroups.Image, Assembly.GetEntryAssembly());
            twain = new TwainSession(appId);
            twain.Open();
            //Todo：在程序32位时，可正常扫描；
            //在程序64位时，不能正常获取扫描仪，并崩溃：找不到TWAINDSM.DLL模块。

            foreach (var s in twain.Select(s => new { DS = s }))
            {
                var item = new ScannerItem(s.DS);
                Scanners.Add(item);
            }

            twain.TransferError += (s, e) =>
            {
                CloseSaveScanner();
               // MessageBox.Show("图片传输错误:" + e.Exception.Message);
            };
            twain.DataTransferred += _session_DataTransferred;
            twain.SourceDisabled += (s, e) =>
            {
                //MessageBox.Show("源数据已清除");
            };
            twain.TransferReady += (s, e) =>
            {
                //MessageBox.Show("数据传输就绪");
            };

            twain.SynchronizationContext = System.Threading.SynchronizationContext.Current;
        }

        //生成图片+预览图片
        private void _session_DataTransferred(object sender, DataTransferredEventArgs e)
        {
            if (IsScanner)
            {
                string docPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
                FilePath = docPath + "\\" + DateTime.Now.ToString("yyyy-MM-dd_hh-mm-ss") + ".png";

                var encoder = new PngBitmapEncoder();
                encoder.Frames.Add(BitmapFrame.Create(e.GetNativeImageStream().ConvertToWpfBitmap(300, 0)));
                var test = encoder.Frames[0];
                FileStream fileStream = new FileStream(FilePath, FileMode.Create, FileAccess.ReadWrite);
                encoder.Save(fileStream);
                fileStream.Close();
                CloseSaveScanner();
            }

            ImageSource img = GenerateThumbnail(e);
            if (img != null)
            {
                App.Current.Dispatcher.BeginInvoke(new Action(() =>
                {
                    Img = img;
                }));
            }
        }

        //图片缩略图
        private ImageSource GenerateThumbnail(DataTransferredEventArgs e)
        {
            BitmapSource img = null;

            switch (e.TransferType)
            {
                case XferMech.Native:
                    using (var stream = e.GetNativeImageStream())
                    {
                        if (stream != null)
                        {
                            // twain.CurrentSource.Capabilities.ICapYResolution.SetValue();
                            img = stream.ConvertToWpfBitmap(300, 0);
                        }
                    }
                    break;
                case XferMech.File:
                    img = new BitmapImage(new Uri(e.FileDataPath));
                    if (img.CanFreeze)
                    {
                        img.Freeze();
                    }
                    break;
                case XferMech.Memory:
                    // TODO: build current image from multiple data-xferred event
                    break;
            }
            return img;
        }

        //预览图片
        private void Preview()
        {
            if (twain.CurrentSource == null) return;

            var windowsPtr = new WindowInteropHelper(Window.GetWindow(App.Current.MainWindow)).Handle;
            twain.CurrentSource.Enable(SourceEnableMode.NoUI, false, windowsPtr);
        }

        private void CloseSaveScanner()
        {
            IsScanner = false;
        }

        private void OpenSaveScanner()
        {
            IsScanner = true;
        }
        /// <summary>
        /// 是否可以创建
        /// </summary>
        /// <returns></returns>
        private bool CanExcuteCreateFile()
        {
            if (Img == null)
                IsEmptyImg = true;
            else
                IsEmptyImg = false;

            return (Img != null);
        }

        //扫描，创建文件
        private void createFile()
        {
            DialogParameters valuePairs = new DialogParameters();
            valuePairs.Add(ParameterNames.DataModel, FilePath);
            RequestClose.Invoke(new DialogResult(ButtonResult.OK, valuePairs));
        }

        private void cancel()
        {
            RequestClose.Invoke(new DialogResult(ButtonResult.Cancel));
        }

        #region 框架
        public bool CanCloseDialog()
        {
            return true;
        }

        public void OnDialogClosed()
        {

        }

        public void OnDialogOpened(IDialogParameters parameters)
        {

        }
        #endregion

    }
}