如何在 .NET MAUI 中查看 PDF（逐步教程）

<Label
    Text="Enter URL to Convert PDF"
    SemanticProperties.HeadingLevel="Level1"
    FontSize="18"
    HorizontalOptions="Center" 
/>
<HorizontalStackLayout
    HorizontalOptions="Center">
    <Border Stroke="White"
            StrokeThickness="2"
            StrokeShape="RoundRectangle 5,5,5,5"
            HorizontalOptions="Center">
        <Entry
            x:Name="URL"
            HeightRequest="50"
            WidthRequest="300" 
            HorizontalOptions="Center"
        />
    </Border>

    <Button
        x:Name="urlPDF"
        Text="Convert URL to PDF"
        Margin="30,0,0,0"
        Clicked="UrlToPdf"
        HorizontalOptions="Center" />
</HorizontalStackLayout>

<Line Stroke="White" X2="1500" />

<Label
    Text="Enter HTML to Convert to PDF"
    SemanticProperties.HeadingLevel="Level2"
    FontSize="18"
    HorizontalOptions="Center" />
<Border 
    Stroke="White"
    StrokeThickness="2"
    StrokeShape="RoundRectangle 5,5,5,5"
    HorizontalOptions="Center">

    <Editor
        x:Name="HTML"
        HeightRequest="200"
        WidthRequest="300" 
        HorizontalOptions="Center"
    />

</Border>

<Button
    x:Name="htmlPDF"
    Text="Convert HTML to PDF"
    Clicked="HtmlToPdf"
    HorizontalOptions="Center" />

<Line Stroke="White" X2="1500" />

<Label
    Text="Convert HTML file to PDF"
    SemanticProperties.HeadingLevel="Level2"
    FontSize="18"
    HorizontalOptions="Center" />

<Button
    x:Name="htmlFilePDF"
    Text="Convert HTML file to PDF"
    Clicked="FileToPdf"
    HorizontalOptions="Center" />

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="PDF_Viewer.MainPage">

    <ScrollView>
        <VerticalStackLayout
            Spacing="25"
            Padding="30,0"
            VerticalOptions="Center">
            <Label
                Text="Enter URL to Convert PDF"
                SemanticProperties.HeadingLevel="Level1"
                FontSize="18"
                HorizontalOptions="Center" 
            />
            <HorizontalStackLayout
                HorizontalOptions="Center">
                <Border Stroke="White"
                        StrokeThickness="2"
                        StrokeShape="RoundRectangle 5,5,5,5"
                        HorizontalOptions="Center">
                    <Entry
                        x:Name="URL"
                        HeightRequest="50"
                        WidthRequest="300" 
                        HorizontalOptions="Center"
                    />
                </Border>

                <Button
                    x:Name="urlPDF"
                    Text="Convert URL to PDF"
                    Margin="30,0,0,0"
                    Clicked="UrlToPdf"
                    HorizontalOptions="Center" />
            </HorizontalStackLayout>

            <Line Stroke="White" X2="1500" />

            <Label
                Text="Enter HTML to Convert to PDF"
                SemanticProperties.HeadingLevel="Level2"
                FontSize="18"
                HorizontalOptions="Center" />
            <Border 
                Stroke="White"
                StrokeThickness="2"
                StrokeShape="RoundRectangle 5,5,5,5"
                HorizontalOptions="Center">

                <Editor
                    x:Name="HTML"
                    HeightRequest="200"
                    WidthRequest="300" 
                    HorizontalOptions="Center"
                />

            </Border>

            <Button
                x:Name="htmlPDF"
                Text="Convert HTML to PDF"
                Clicked="HtmlToPdf"
                HorizontalOptions="Center" />

            <Line Stroke="White" X2="1500" />

            <Label
                Text="Convert HTML file to PDF"
                SemanticProperties.HeadingLevel="Level2"
                FontSize="18"
                HorizontalOptions="Center" />

            <Button
                x:Name="htmlFilePDF"
                Text="Convert HTML file to PDF"
                Clicked="FileToPdf"
                HorizontalOptions="Center" />
        </VerticalStackLayout>
    </ScrollView>

</ContentPage>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace PDF_Viewer
{
    public partial class SaveService
    {
        public partial void SaveAndView(string filename, string contentType, MemoryStream stream);
    }
}

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Text
Imports System.Threading.Tasks

Namespace PDF_Viewer
	Partial Public Class SaveService
		Public Partial Private Sub SaveAndView(ByVal filename As String, ByVal contentType As String, ByVal stream As MemoryStream)
		End Sub
	End Class
End Namespace

using Windows.Storage;
using Windows.Storage.Pickers;
using Windows.Storage.Streams;
using Windows.UI.Popups;

namespace PDF_Viewer
{
    public partial class SaveService
    {
        public async partial void SaveAndView(string filename, string contentType, MemoryStream stream)
        {
            StorageFile stFile;
            string extension = Path.GetExtension(filename);
            //Gets process windows handle to open the dialog in application process.
            IntPtr windowHandle = System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle;
            if (!Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons"))
            {
                //Creates file save picker to save a file.
                FileSavePicker savePicker = new FileSavePicker();
                savePicker.DefaultFileExtension = ".pdf";
                savePicker.SuggestedFileName = filename;
                //Saves the file as PDF file.
                savePicker.FileTypeChoices.Add("PDF", new List<string>() { ".pdf" });

                WinRT.Interop.InitializeWithWindow.Initialize(savePicker, windowHandle);
                stFile = await savePicker.PickSaveFileAsync();
            }
            else
            {
                StorageFolder local = ApplicationData.Current.LocalFolder;
                stFile = await local.CreateFileAsync(filename, CreationCollisionOption.ReplaceExisting);
            }
            if (stFile != null)
            {
                using (IRandomAccessStream zipStream = await stFile.OpenAsync(FileAccessMode.ReadWrite))
                {
                    //Writes compressed data from memory to file.
                    using Stream outstream = zipStream.AsStreamForWrite();
                    outstream.SetLength(0);
                    //Saves the stream as file.
                    byte [] buffer = stream.ToArray();
                    outstream.Write(buffer, 0, buffer.Length);
                    outstream.Flush();
                }
                //Create message dialog box.
                MessageDialog msgDialog = new("Do you want to view the document?", "File has been created successfully");
                UICommand yesCmd = new("Yes");
                msgDialog.Commands.Add(yesCmd);
                UICommand noCmd = new("No");
                msgDialog.Commands.Add(noCmd);

                WinRT.Interop.InitializeWithWindow.Initialize(msgDialog, windowHandle);

                //Showing a dialog box.
                IUICommand cmd = await msgDialog.ShowAsync();
                if (cmd.Label == yesCmd.Label)
                {
                    //Launch the saved file.
                    await Windows.System.Launcher.LaunchFileAsync(stFile);
                }
            }
        }
    }
}

Imports Windows.Storage
Imports Windows.Storage.Pickers
Imports Windows.Storage.Streams
Imports Windows.UI.Popups

Namespace PDF_Viewer
	Partial Public Class SaveService
		Public Async Sub SaveAndView(ByVal filename As String, ByVal contentType As String, ByVal stream As MemoryStream)
			Dim stFile As StorageFile
			Dim extension As String = Path.GetExtension(filename)
			'Gets process windows handle to open the dialog in application process.
			Dim windowHandle As IntPtr = System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle
			If Not Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons") Then
				'Creates file save picker to save a file.
				Dim savePicker As New FileSavePicker()
				savePicker.DefaultFileExtension = ".pdf"
				savePicker.SuggestedFileName = filename
				'Saves the file as PDF file.
				savePicker.FileTypeChoices.Add("PDF", New List(Of String)() From {".pdf"})

				WinRT.Interop.InitializeWithWindow.Initialize(savePicker, windowHandle)
				stFile = Await savePicker.PickSaveFileAsync()
			Else
				Dim local As StorageFolder = ApplicationData.Current.LocalFolder
				stFile = Await local.CreateFileAsync(filename, CreationCollisionOption.ReplaceExisting)
			End If
			If stFile IsNot Nothing Then
				Using zipStream As IRandomAccessStream = Await stFile.OpenAsync(FileAccessMode.ReadWrite)
					'Writes compressed data from memory to file.
					Using outstream As Stream = zipStream.AsStreamForWrite()
						outstream.SetLength(0)
						'Saves the stream as file.
						Dim buffer() As Byte = stream.ToArray()
						outstream.Write(buffer, 0, buffer.Length)
						outstream.Flush()
					End Using
				End Using
				'Create message dialog box.
				Dim msgDialog As New MessageDialog("Do you want to view the document?", "File has been created successfully")
				Dim yesCmd As New UICommand("Yes")
				msgDialog.Commands.Add(yesCmd)
				Dim noCmd As New UICommand("No")
				msgDialog.Commands.Add(noCmd)

				WinRT.Interop.InitializeWithWindow.Initialize(msgDialog, windowHandle)

				'Showing a dialog box.
				Dim cmd As IUICommand = Await msgDialog.ShowAsync()
				If cmd.Label = yesCmd.Label Then
					'Launch the saved file.
					Await Windows.System.Launcher.LaunchFileAsync(stFile)
				End If
			End If
		End Sub
	End Class
End Namespace

private void HtmlToPdf(object sender, EventArgs e)
{
    if (HTML.Text != null)
    {
        var renderer = new IronPdf.ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf(HTML.Text);
        SaveService saveService = new SaveService();
        saveService.SaveAndView("IronPDF HTML string.pdf", "application/pdf", pdf.Stream);
        DisplayAlert("Success", "PDF from HTML Created!", "OK");
    }
    else
    {
        DisplayAlert("Error", "Field can't be empty! \nPlease enter valid HTML!", "OK");
    }
}

Imports Microsoft.VisualBasic

Private Sub HtmlToPdf(ByVal sender As Object, ByVal e As EventArgs)
	If HTML.Text IsNot Nothing Then
		Dim renderer = New IronPdf.ChromePdfRenderer()
		Dim pdf = renderer.RenderHtmlAsPdf(HTML.Text)
		Dim saveService As New SaveService()
		saveService.SaveAndView("IronPDF HTML string.pdf", "application/pdf", pdf.Stream)
		DisplayAlert("Success", "PDF from HTML Created!", "OK")
	Else
		DisplayAlert("Error", "Field can't be empty! " & vbLf & "Please enter valid HTML!", "OK")
	End If
End Sub

private void FileToPdf(object sender, EventArgs e)
{
    var renderer = new IronPdf.ChromePdfRenderer();
    var pdf = renderer.RenderHtmlFileAsPdf(@"C:\Users\Administrator\Desktop\index.html");
    SaveService saveService = new SaveService();
    saveService.SaveAndView("HTML File to PDF.pdf", "application/pdf", pdf.Stream);
    DisplayAlert("Success", "PDF from File Created!", "OK");
}

Private Sub FileToPdf(ByVal sender As Object, ByVal e As EventArgs)
	Dim renderer = New IronPdf.ChromePdfRenderer()
	Dim pdf = renderer.RenderHtmlFileAsPdf("C:\Users\Administrator\Desktop\index.html")
	Dim saveService As New SaveService()
	saveService.SaveAndView("HTML File to PDF.pdf", "application/pdf", pdf.Stream)
	DisplayAlert("Success", "PDF from File Created!", "OK")
End Sub