PDFOffice_Windows_exe/PDF Office/ViewModels/ViewContentViewModel.cs

using Microsoft.Win32;
using Prism.Commands;
using Prism.Mvvm;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ComPDFKitViewer.PdfViewer;
using Prism.Regions;
using DryIoc;
using System.Diagnostics;
using Prism.Services.Dialogs;
using PDF_Office.CustomControl;
using PDF_Office.Model;
using System.Windows;
using System.Windows.Controls;

namespace PDF_Office.ViewModels
{

    public class ViewContentViewModel : BindableBase, INavigationAware
    {
        private CPDFViewer PDFViewer { get; set; }

        private MainContentViewModel mainViewModel { get; set; }

        public IRegionManager region;

        public IDialogService dialogs;

        public string ViwerRegionName { get; set; }

        public string BOTARegionName { get; set; }

        public string PropertyRegionName { get; set; }

        public string ToolContentRegionName { get; set; }

        public DelegateCommand LoadFile { get; set; }

        public DelegateCommand Load { get; set; }

        public DelegateCommand<object> TabControlSelectionChangedCommand { get; set; }


        private int gridToolRow = 1;
        /// <summary>
        /// 控制ToolContent的Row
        /// </summary>
        public int GridToolRow
        {
            get { return gridToolRow; }
            set
            {
                SetProperty(ref gridToolRow, value);
            }
        }

        private int gridToolRowSpan = 3;
        /// <summary>
        /// 控制ToolContent的RowSpan
        /// </summary>
        public int GridToolRowSpan
        {
            get { return gridToolRowSpan; }
            set
            {
                SetProperty(ref gridToolRowSpan, value);
            }
        }

        private Visibility toolContentVisible = Visibility.Visible;
        /// <summary>
        /// 控制Content的显示
        /// 留意：显示前需要先注入内容、设置好行和跨行数
        /// </summary>
        public Visibility ToolContentVisible
        {
            get { return toolContentVisible; }
            set
            {
                SetProperty(ref toolContentVisible, value);
            }
        }


        private bool isOpenFile = false;

        /// <summary>
        /// 鼠标滚轮缩放的缩放值
        /// </summary>
        private double[] zoomLevel = { 1.00f, 10, 25, 50, 75, 100, 125, 150, 200, 300, 400, 600, 800, 1000 };

        public ViewContentViewModel(IRegionManager regionManager,IDialogService dialogService)
        {
            region = regionManager;
            dialogs = dialogService;

            LoadFile = new DelegateCommand(loadFile);
            Load = new DelegateCommand(LoadControl);
            TabControlSelectionChangedCommand = new DelegateCommand<object>(TabControlSelectonChangedEvent);

            ViwerRegionName = Guid.NewGuid().ToString();
            BOTARegionName = Guid.NewGuid().ToString();
            PropertyRegionName = Guid.NewGuid().ToString();
            ToolContentVisible = Visibility.Visible;
            ToolContentRegionName = Guid.NewGuid().ToString();
            ToolContentVisible = Visibility.Collapsed;
        }

        private void LoadControl()
        {
            //在构造函数中使用Region需要借助Dispatcher 确保UI已经加载完成,加载BOTA区域
            System.Windows.Application.Current.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Send, new Action(() =>
            {
                region.RequestNavigate(BOTARegionName, "BOTAContent");
            }
            ));
        }

        /// <summary>
        /// 将PDFViwer添加到Region
        /// </summary>
        private void loadFile()
        {
            PDFViewer.MouseWheelZoomHandler += PdfViewer_MouseWheelZoomHandler;
            region.AddToRegion(ViwerRegionName, PDFViewer);
        }

        private void TabControlSelectonChangedEvent(object e)
        {
            var args = e as SelectionChangedEventArgs;
            if(args!=null)
            {
                var item = args.AddedItems[0] as TabItem;
                if(item.Name=="TabItemPageEdit")
                {
                    EnterPageEdit();
                }
                else
                {
                    ExitPageEdit();
                }
            }
        }

        #region PDFViewer鼠标滚轮缩放事件
        public void PdfViewer_MouseWheelZoomHandler(object sender, bool e)
        {
            double newZoom = CheckZoomLevel(PDFViewer.ZoomFactor + (e ? 0.01 : -0.01), e);
            PDFViewer.Zoom(newZoom);
        }

        private double CheckZoomLevel(double zoom, bool IsGrowth)
        {
            double standardZoom = 100;
            if (zoom <= 0.01)
            {
                return 0.01;
            }
            if (zoom >= 10)
            {
                return 10;
            }

            zoom *= 100;
            for (int i = 0; i < zoomLevel.Length - 1; i++)
            {
                if (zoom > zoomLevel[i] && zoom <= zoomLevel[i + 1] && IsGrowth)
                {
                    standardZoom = zoomLevel[i + 1];
                    break;
                }
                if (zoom >= zoomLevel[i] && zoom < zoomLevel[i + 1] && !IsGrowth)
                {
                    standardZoom = zoomLevel[i];
                    break;
                }
            }
            return standardZoom / 100;
        }
        #endregion

        #region Navigate
        public void OnNavigatedTo(NavigationContext navigationContext)
        {
            if (isOpenFile)
                return;

            var mainVM = navigationContext.Parameters[ParameterNames.MainViewModel] as MainContentViewModel;
            if (mainVM != null)
            {
                mainViewModel = mainVM;
            }
            var pdfview = navigationContext.Parameters[ParameterNames.PDFViewer] as CPDFViewer;
            if (pdfview!=null)
            {
                PDFViewer = pdfview;
                loadFile();
            }


            isOpenFile = true;
        }

        public bool IsNavigationTarget(NavigationContext navigationContext)
        {
            return true;
        }

        public void OnNavigatedFrom(NavigationContext navigationContext)
        {

        }
        #endregion

        /// <summary>
        /// 显示前添加内容到Region
        /// </summary>
        /// <param name="isPageEdit"></param>
        private void ShowToolContent(bool isPageEdit = true)
        {
            //显示页面编辑
            if(isPageEdit)
            {
                if(GridToolRow!=1)
                {
                    GridToolRow = 1;
                }

                if(GridToolRowSpan!=3)
                {
                    GridToolRowSpan = 3;
                }
         
            }
            else
            {
                //显示其他工具模式 如密文、水印等
                GridToolRow = 0;
                GridToolRowSpan = 4;
            }
            ToolContentVisible = Visibility.Visible;
        }

        /// <summary>
        /// 进入页面编辑模式
        /// </summary>
        private void EnterPageEdit()
        {
            NavigationParameters param = new NavigationParameters();
            param.Add(ParameterNames.PDFViewer, PDFViewer);
            param.Add(ParameterNames.ViewContentViewModel,this);
            region.RequestNavigate(ToolContentRegionName, "PageEditContent" , param);
            ShowToolContent();
         
        }

        /// <summary>
        /// 退出页面编辑模式，隐藏ToolContent
        /// </summary>

        public void ExitPageEdit()
        {
            ToolContentVisible = Visibility.Collapsed;
        }
    }
}