使用 PdfSharp.Xamarin.Forms 创建 PDF 时无法显示 ListView 数据

Question

我是xamarin的新手，我正在使用PdfSharp.Xamarin.Forms nuget在Xamarin表单中为Android和iOS创建PDF。问题是我无法呈现列表视图。他们已经提到了它，并且需要为它编写一个渲染器。但我不知道如何创建和绑定它。

我就是这样做的。

<Grid x:Name="mainGrid">
<ScrollView>
<StackLayout Padding="4" Orientation="Vertical">
<!--<Image HeightRequest="80" Source="logojpeg.jpg" Margin="0,0,0,5"/>-->
<Label FontSize="18" TextColor="Black" FontFamily="{StaticResource timesNewRomanBold}" HorizontalOptions="CenterAndExpand" Text="Monthly Motor Renew List of Jayasekara (900585) as at January, 2020"/>
<Label FontSize="18" TextColor="Black" FontFamily="{StaticResource timesNewRomanBold}" HorizontalOptions="CenterAndExpand" Text="Report generated on 27 December, 2019" Margin="0,0,0,5"/>
<ListView x:Name="renewListView"
Footer=""
pdf:PdfRendererAttributes.ListRendererDelegate="{StaticResource PDFSampleListRendererDelegate}"
BackgroundColor="White"
SeparatorVisibility="None"
HasUnevenRows="True">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell IsEnabled="false">

</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</ScrollView>
</Grid>

在代码隐藏中。

public partial class MotorRenewalFinalPrint : ContentPage
{
public MotorRenewalFinalPrint()
{
InitializeComponent();
}
public MotorRenewalFinalPrint (List<MotorRenewalPrintData> newdd)
{
InitializeComponent ();
Title = "Save as PDF";
renewListView.ItemsSource = newdd;
}
private void pdf_Clicked(object sender, EventArgs e)
{
var pdf = PDFManager.GeneratePDFFromView(mainGrid);
var fileManager = DependencyService.Get<IFileIO>();
string filePath = Path.Combine(fileManager.GetMyDocumentsPath(), "formpdf.pdf");
DependencyService.Get<IPdfSave>().Save(pdf, filePath);
DependencyService.Get<IPDFPreviewProvider>().TriggerPreview(filePath);
}
}

更新。。。

主类

public partial class MainPage : ContentPage
{
private List<Customer> Cus = new List<Customer>();
public MainPage()
{
InitializeComponent();
Customer ss1 = new Customer { Names = "test1", Ages = "10"};
Customer ss2 = new Customer { Names = "test2", Ages = "30" };
Cus.Add(ss1);
Cus.Add(ss2);
//rListView.ItemsSource = Cus;
}
private void Button_Clicked(object sender, System.EventArgs e)
{
var pdf = PDFManager.GeneratePDFFromView(mainGrid);
var fileManager = DependencyService.Get<IFileIO>();
string filePath = Path.Combine(fileManager.GetMyDocumentsPath(), "testpdf.pdf");
DependencyService.Get<IPdfSave>().Save(pdf, filePath);
DependencyService.Get<IPDFPreviewProvider>().TriggerPreview(filePath);
}
}

视图

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:TestPDF"
xmlns:pdf="clr-namespace:PdfSharp.Xamarin.Forms;assembly=PdfSharp.Xamarin.Forms"
x:Class="TestPDF.MainPage">
<ContentPage.Resources>
<ResourceDictionary>
<local:PDFSampleListRendererDelegate  x:Key="PDFSampleListRendererDelegate" />
</ResourceDictionary>
</ContentPage.Resources>
<ContentPage.Content>
<Grid x:Name="mainGrid">
<ScrollView>
<StackLayout Margin="0,0,0,5">
<Label Text="Welcome to Xamarin.Forms!" HorizontalOptions="CenterAndExpand" TextColor="Black" FontSize="18" VerticalOptions="Center" />
<ListView pdf:PdfRendererAttributes.ListRendererDelegate="{DynamicResource PDFSampleListRendererDelegate}" HeightRequest="150"/>
<Button Text="click" Clicked="Button_Clicked"/>
</StackLayout>
</ScrollView>
</Grid>
</ContentPage.Content>
</ContentPage>

PDFSampleListRendererDelegate

public class PDFSampleListRendererDelegate : PdfListViewRendererDelegate
{
public override void DrawCell(ListView listView, int section, int row, XGraphics page, XRect bounds, double scaleFactor)
{
XFont font = new XFont("times" ?? GlobalFontSettings.FontResolver.DefaultFontName, 15);
var yourObject = (listView.ItemsSource as List<Customer>).ElementAt(row);
page.DrawString(yourObject.Names, font, XBrushes.Black, bounds,
new XStringFormat
{
LineAlignment = XLineAlignment.Center,
Alignment = XStringAlignment.Center,
});
}
public override void DrawFooter(ListView listView, int section, XGraphics page, XRect bounds, double scaleFactor)
{
base.DrawFooter(listView, section, page, bounds, scaleFactor);
}
public override double GetFooterHeight(ListView listView, int section)
{
return base.GetFooterHeight(listView, section);
}
}

Answer 1

你应该覆盖DrawCell方法

即：

public override void DrawCell(ListView listView, int section, int row, XGraphics page, XRect bounds, double scaleFactor)
{
XFont font = new XFont(yourCustomFont ?? GlobalFontSettings.FontResolver.DefaultFontName, label.FontSize * scaleFactor);
var yourObject = (listView.ItemSource as List<YourObjType>).ElementAt(row);
page.DrawString(yourObject.Text, font, XColors.Black, bounds,
new XStringFormat {
LineAlignment = XLineAlignment.Center,
Alignment = XStringAlignment.Center,
});
}