WPF中查看PDF文件

需要打開PDF文件時，我們第一印象就是使用Adobe Reader。在開發中，經常會遇到需要展示PDF文件的需求。我們會借助於Adobe Reader的Active控件來實現。不過這需要客戶的機器上安裝有Adobe Reader，並且使用Adobe Reader的Active控件會在頂部有一個隱藏不了的工具欄。這樣顯然不合理。

在Github上看到一個非常好的WPF中承載PDF文件的類庫。

https://github.com/reliak/moonpdf

使用非常簡單，本篇博客將介紹使用MoonPdf類庫來展示PDF文件。在Sourceforge上下載到MoonPdf編譯好的Dll。下面通過一個WPF程序來演示，

1. 工程中添加對MoonPdfLib.dll的引用，另外記得將libmupdf.dll放置於WPF工程Bin文件下。

2. 代碼：

XAML:

<Window x:Class="WPFPdfViewer.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:mpp="clr-namespace:MoonPdfLib;assembly=MoonPdfLib"
        xmlns:local="clr-namespace:WPFPdfViewer"
        mc:Ignorable="d"
        Title="WPF Pdf Viewer" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <Border Background="#f0f0f0">
            <StackPanel HorizontalAlignment="Left" Orientation="Horizontal">
                <Button Content="文件" Width="50" Click="FileButton_Click" Margin="5,5"/>
                
                <Button Content="放大" Width="50" Click="ZoomInButton_Click" Margin="0,5"/>

                <Button Content="縮小" Width="50" Click="ZoomOutButton_Click" Margin="5,5"/>

                <Button Content="100%" Width="50" Click="NormalButton_Click" Margin="0,5"/>

                <Button Content="整頁" Width="50" Click="FitToHeightButton_Click" Margin="5,5"/>

                <Button Content="單頁" Width="50" Click="SinglePageButton_Click" Margin="0,5"/>

                <Button Content="雙頁" Width="50" Click="FacingButton_Click" Margin="5,5"/>
            </StackPanel>
        </Border>

        <Border Background="#d3d3d3" Grid.Row="1">
            <mpp:MoonPdfPanel x:Name="moonPdfPanel" Background="LightGray" ViewType="SinglePage" PageRowDisplay="ContinuousPageRows" PageMargin="0,2,4,2" AllowDrop="True"/>
        </Border>
    </Grid>
</Window>

C#:

    public partial class MainWindow : Window
    {
        private bool _isLoaded = false;
        public MainWindow()
        {
            InitializeComponent();
        }

        private void FileButton_Click(object sender, RoutedEventArgs e)
        {
            var dialog = new OpenFileDialog();

            if (dialog.ShowDialog().GetValueOrDefault())
            {
                string filePath = dialog.FileName;

                try
                {
                    moonPdfPanel.OpenFile(filePath);
                    _isLoaded = true;
                }
                catch (Exception)
                {
                    _isLoaded = false;
                }
            }
        }

        private void ZoomInButton_Click(object sender, RoutedEventArgs e)
        {
            if(_isLoaded)
            {
                moonPdfPanel.ZoomIn();
            }
        }

        private void ZoomOutButton_Click(object sender, RoutedEventArgs e)
        {
            if(_isLoaded)
            {
                moonPdfPanel.ZoomOut();
            }
        }

        private void NormalButton_Click(object sender, RoutedEventArgs e)
        {
            if(_isLoaded)
            {
                moonPdfPanel.Zoom(1.0);
            }
        }

        private void FitToHeightButton_Click(object sender, RoutedEventArgs e)
        {
            moonPdfPanel.ZoomToHeight();
        }

        private void FacingButton_Click(object sender, RoutedEventArgs e)
        {
            moonPdfPanel.ViewType = MoonPdfLib.ViewType.Facing;
        }

        private void SinglePageButton_Click(object sender, RoutedEventArgs e)
        {
            moonPdfPanel.ViewType = MoonPdfLib.ViewType.SinglePage;
        }
    }

3. 運行程序，打開PDF文件，

代碼點擊這里下載。

MoonPdf的原理是將Pdf文件轉成了圖片文件，然后再顯示出來的。MoonPdf的開發者在CodePlex上的這篇文章介紹了MoonPdf了，非常不錯。

感謝您的閱讀。