打印前使用WPF窗口作为视觉模板

您可以使用您提到的文章的第一部分来实现这一点：WPF打印第1部分

即使没有显示窗口，PrintVisual方法似乎也能工作。

这里有一个小例子：

带有单个按钮的主窗口：

MainWindow _barcodeWindow = new MainWindow("A1b2c3D4e5");
private void Button_Click(object sender, RoutedEventArgs e)
{
    _barcodeWindow.Print();
    _barcodeWindow.ShowDialog();
}

"模板"窗口：

<StackPanel Name="StuffToPrint">
    <Label>Some sample text</Label>
    <Label Name="BarCodeLabel" FontSize="40" Margin="96" FontFamily="Code 128"/>
    <Label>More sample text</Label>
</StackPanel>

及其背后的代码：

public MainWindow(string code)
{
    InitializeComponent();
    BarCodeLabel.Content = BarcodeConverter128.StringToBarcode(code);
}
public void Print()
{
    PrintDialog dlg = new PrintDialog();
    if (dlg.ShowDialog() == true)
    {
        dlg.PrintVisual(StuffToPrint, "Barcode");
    }
}

如果我误解了您的需求，我很抱歉，但我希望我的例子能对您有所帮助。这是一个完整而简单的例子——只需创建这些文件并进行测试！

View.xaml

<DockPanel x:Class="WpfApplication1.View"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d" 
             Height="300" Width="400">
    <StackPanel Orientation="Vertical">
        <StackPanel Orientation="Horizontal">
            <TextBlock Margin="10" Text="Static Text"/>
            <Button Margin="10">Any control can be here</Button>
        </StackPanel>
        <StackPanel Orientation="Horizontal">
            <TextBlock Margin="10" Width="100"  Text="{Binding Text1}"/>
            <TextBox Width="100" Text="{Binding Text2}"/>
        </StackPanel>
    </StackPanel>
</DockPanel>

查看.xaml.cs

using System.Windows.Controls;
namespace WpfApplication1
{
    public partial class View : DockPanel
    {
        public View()
        {
            InitializeComponent();
        }
    }
}

ViewModel.cs

namespace WpfApplication1
{
    public  class ViewModel
    {
        public string Text1 { get; set; }
        public string Text2 { get; set; }
    }
}

使用下面的代码用数据填充ViewModel，并将其打印到文件中

var path = "newdoc.xps";
FixedDocument fixedDoc = new FixedDocument();
PageContent pageContent = new PageContent();
FixedPage fixedPage = new FixedPage();
fixedPage.Width = 11.69 * 96;
fixedPage.Height = 8.27 * 96;
var pageSize = new System.Windows.Size(11.0 * 96.0, 8.5 * 96.0);
View v = new View();
ViewModel vm = new ViewModel();
vm.Text1 = "MyText1";
vm.Text2 = "MyText2";
v.DataContext = vm;
v.UpdateLayout();
v.Height = pageSize.Height;
v.Width = pageSize.Width;
v.UpdateLayout();
fixedPage.Children.Add(v);
((System.Windows.Markup.IAddChild)pageContent).AddChild(fixedPage);
fixedDoc.Pages.Add(pageContent);
if (File.Exists(path))
    File.Delete(path);
XpsDocument xpsd = new XpsDocument(path, FileAccess.ReadWrite);
XpsDocumentWriter xw = XpsDocument.CreateXpsDocumentWriter(xpsd);
xw.Write(fixedDoc);
xpsd.Close();

如何打印顶级UIElement而不是整个窗口？

例如，如果您有一个窗口：

<Window x:Class="WpfApplicationGrid.Window_Template1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window_Template1" Height="300" Width="300">
    <Grid Name="MainGrid" >
        <!--some content....-->
    </Grid>
</Window>
//-------------------------
public Grid GetMyGrid()
{
   return MainGrid;
}

打印：

 Window_Template1 myWindow = new Window_Template1();
// clone the grid you want to print, so the exception you mentioned won't happen:
Grid clonedGrid = null;
string uiToSave = XamlWriter.Save(myWindow.GetMyGrid());
using (StringReader stringReader = new StringReader(uiToSave))
{
      using (XmlReader xmlReader = XmlReader.Create(stringReader))
      {
          clonedGrid = (Grid)XamlReader.Load(xmlReader);
      }
}
// for some reason you have to close the window even if there was no Show() called
// to properly dispose of it
// otherwise there may be some unpredictable behaviour (maybe I have something odd in my project settings...)
myWindow.Close();
PrintDialog pd = new PrintDialog();
FixedDocument document = new FixedDocument();
document.DocumentPaginator.PageSize = new System.Windows.Size(pd.PrintableAreaWidth, pd.PrintableAreaHeight);
// remember to set sizes again, if they're not set in xaml, for example:
clonedGrid.Height = document.DocumentPaginator.PageSize.Height;
clonedGrid.Width = document.DocumentPaginator.PageSize.Width;
clonedGrid.UpdateLayout();
FixedPage page1 = new FixedPage();
page1.Width = document.DocumentPaginator.PageSize.Width;
page1.Height = document.DocumentPaginator.PageSize.Height;
// this will add the content of the whole grid to the page without problem
page1.Children.Add(clonedGrid);
PageContent page1Content = new PageContent();
((IAddChild)page1Content).AddChild(page1);
document.Pages.Add(page1Content);
// then print...