将 WPF 页面导出为 PDF 文件

引言

由于没有开箱即用的解决方案来创建 PDF 报告（或者我没有找到任何解决方案），我们创建了一组类和说明来支持此操作。

背景

在开发一个 WPF 应用程序（要在 PC 和带有触摸屏的笔记本电脑上使用）后，我们被要求在该应用程序中创建创建 PDF 报告的可能性。在网上搜索了很多内容并尝试了我们找到的内容之后，我们提出了一个相当简单的解决方案。

使用代码

在我们的应用程序中，我们使用带有菜单和命令按钮的主屏幕。然后，每个菜单项或命令按钮都可以在此主屏幕中打开一个用户控件。这样，我们可以跟踪导航并实现返回上一页和在同一主题中前进的可能性。无论如何，我们希望在 PDF 报告中包含这些用户控件的某种屏幕截图。

我们为报告创建了三个类。

1. ReportDocument

Public Class ReportDocument
    Private mReportDocument As New FixedDocument
    Public Property ReportDocument() As FixedDocument
        Get
            Return mReportDocument
        End Get
        Set(ByVal value As FixedDocument)
            mReportDocument = value
        End Set
    End Property
 
    Private mReportPage As New List(Of FixedPage)
    Public Property ReportPage() As List(Of FixedPage)
        Get
            Return mReportPage
        End Get
        Set(ByVal value As List(Of FixedPage))
            mReportPage = value
        End Set
    End Property
 
    Private mReportWidth As Double
    Public Property ReportWidth() As Double
        Get
            Return mReportWidth
        End Get
        Set(ByVal value As Double)
            mReportWidth = value
        End Set
    End Property
 
    Private mReportHeight As Double
    Public Property ReportHeight() As Double
        Get
            Return mReportHeight
        End Get
        Set(ByVal value As Double)
            mReportHeight = value
        End Set
    End Property
 
    Public Sub New(dblWidth As Double, dblHeight As Double)
        mReportWidth = dblWidth
        mReportHeight = dblHeight
    End Sub
 
    Public Function CreateReport() As FixedDocument
        'ADD PAGES TO CONTENT TO DOCUMENT
        mReportDocument.DocumentPaginator.PageSize = New Size(mReportWidth, mReportHeight)
        For Each itemElement In mReportPage
            Dim pagContent As New PageContent
            DirectCast(pagContent, IAddChild).AddChild(itemElement)
            mReportDocument.Pages.Add(pagContent)
        Next
        Return mReportDocument
    End Function
 
End Class

我们需要有一个具有宽度和高度（在初始化时定义）的 FixedDocument 和一个页面列表 (ReportPages)。函数 CreateReport 会将每个页面作为 PageContent 添加到 FixedDocument。

2. ReportPage

Public Class ReportPage
 
    Private mReportGrid As New Grid
    Public Property ReportGrid() As Grid
        Get
            Return mReportGrid
        End Get
        Set(ByVal value As Grid)
            mReportGrid = value
        End Set
    End Property
 
    Private mReportWidth As Double
    Public Property ReportWidth() As Double
        Get
            Return mReportWidth
        End Get
        Set(ByVal value As Double)
            mReportWidth = value
        End Set
    End Property
 
    Private mReportHeight As Double
    Public Property ReportHeight() As Double
        Get
            Return mReportHeight
        End Get
        Set(ByVal value As Double)
            mReportHeight = value
        End Set
    End Property
 
    Public Sub New(dblWidth As Double, dblheight As Double, blnHeader As Boolean, blnFooter As Boolean)
        mReportHeight = dblheight
        mReportWidth = dblWidth
        'define grid
        mReportGrid.Margin = New Thickness(0)
        mReportGrid.VerticalAlignment = Windows.VerticalAlignment.Stretch
        mReportGrid.HorizontalAlignment = Windows.HorizontalAlignment.Stretch
        'CREATE ROW DEFINITION
        Dim grdRow1 As New RowDefinition
        Dim grdRow2 As New RowDefinition
        Dim grdRow3 As New RowDefinition
        Dim intLessHeight As Integer = 0
        If blnHeader = True Then
            grdRow1.Height = New GridLength(70)
            intLessHeight += 70
        End If
        If blnFooter = True Then
            grdRow3.Height = New GridLength(50)
            intLessHeight += 50
        End If
        grdRow2.Height = New GridLength(mReportHeight - intLessHeight)
        mReportGrid.RowDefinitions.Add(grdRow1)
        mReportGrid.RowDefinitions.Add(grdRow2)
        mReportGrid.RowDefinitions.Add(grdRow3)
    End Sub
 
    Public Sub AddHeader(objHeader As Object)
        Dim uctHeaderCode As New UserControl
        uctHeaderCode.Content = objHeader
 
        Dim stpHeader As New StackPanel
        stpHeader.Orientation = Orientation.Vertical
        stpHeader.Width = mReportWidth - 80
        stpHeader.Margin = New Thickness(0, 20, 0, 0)
        stpHeader.VerticalAlignment = Windows.VerticalAlignment.Top
        stpHeader.Children.Add(uctHeaderCode)
        Grid.SetRow(stpHeader, 0)
 
        mReportGrid.Children.Add(stpHeader)
    End Sub
 
    Public Sub AddFooter(strFooter As String)
        Dim txtFooter As New TextBlock
        txtFooter.Width = mReportWidth - 150
        txtFooter.Margin = New Thickness(0)
        txtFooter.FontSize = 8
        txtFooter.HorizontalAlignment = HorizontalAlignment.Left
        txtFooter.TextWrapping = TextWrapping.WrapWithOverflow
        txtFooter.Text = strFooter
 
        Dim txtDatePage As New TextBlock
        txtDatePage.Width = 100
        txtDatePage.Margin = New Thickness(60, 0, 0, 0)
        txtDatePage.FontSize = 8
        txtDatePage.HorizontalAlignment = HorizontalAlignment.Right
        txtDatePage.TextWrapping = TextWrapping.WrapWithOverflow
        txtDatePage.Text = Format(Date.Today, "dd/MM/yyyy").ToString
 
        Dim stpFooter As New StackPanel
        stpFooter.Orientation = Orientation.Horizontal
        stpFooter.Width = mReportWidth - 50
        stpFooter.Margin = New Thickness(0, 0, 0, 20)
        stpFooter.VerticalAlignment = Windows.VerticalAlignment.Bottom
        stpFooter.Children.Add(txtFooter)
        stpFooter.Children.Add(txtDatePage)
        Grid.SetRow(stpFooter, 2)
 
        mReportGrid.Children.Add(stpFooter)
    End Sub
 
    Public Sub AddContent(elElement As System.Windows.UIElement)
 
        Grid.SetRow(elElement, 1)
 
        mReportGrid.Children.Add(elElement)
    End Sub
 
    Private Function CreateLineUnderHeader() As Line
        Dim LinLine As New Line
        LinLine.StrokeThickness = 1
        LinLine.X1 = 20
        LinLine.Y1 = 60
        LinLine.X2 = mReportWidth - 20
        LinLine.Y2 = 60
        LinLine.Stroke = Brushes.Black
        Return LinLine
    End Function
 
    Private Function CreateLineAboveFooter() As Line
        Dim LinLine As New Line
        LinLine.StrokeThickness = 1
        LinLine.X1 = 20
        LinLine.Y1 = mReportHeight - 55
        LinLine.X2 = mReportWidth - 20
        LinLine.Y2 = mReportHeight - 55
        LinLine.Stroke = Brushes.Black
        Return LinLine
    End Function
 
    Public Function CreateReportPage(blnWithLineUnderHeader As Boolean, blnWithLineAboveFooter As Boolean)
        Dim tmpPage As New FixedPage
        tmpPage.Width = mReportWidth
        tmpPage.Height = mReportHeight
        tmpPage.Children.Add(mReportGrid)
        If blnWithLineUnderHeader Then tmpPage.Children.Add(CreateLineUnderHeader)
        If blnWithLineAboveFooter Then tmpPage.Children.Add(CreateLineAboveFooter)
        Return tmpPage
    End Function
 
End Class

ReportPage 包含一个网格，该网格具有与文档相同的宽度和高度。在我们的例子中，这个网格包含 3 行：一个页眉、一些内容（我们的用户控件）和一个页脚。由于我们的页眉和页脚是相同的，我们添加了一些方法来添加它们。我们的页眉包含有关我们的“客户”的信息，我们的页脚包含一些法律信息。

我们可以通过 AddContent 方法向此页面添加内容，该方法接受一个 UiElement 作为参数。我们添加了另一个类 (ReportContent) 的 stackpanel，其中包含我们的用户控件、标签等。

然后我们调用函数 CreateReportPage，它将网格添加到 fixedpage 并返回此 fixedpage。此 fixedpage 将被添加到我们的 ReportDocument 的页面列表中（参见上文）。

3. ReportContent

Public Class ReportContent
 
    Enum enmTypeOfControl
        usercontrol
        textBlock
    End Enum
 
    Private mReportStackPanel As New StackPanel
    Public Property ReportStackPanel() As StackPanel
        Get
            Return mReportStackPanel
        End Get
        Set(ByVal value As StackPanel)
            mReportStackPanel = value
        End Set
    End Property
 
    Private mReportWidth As Double
    Public Property ReportWidth() As Double
        Get
            Return mReportWidth
        End Get
        Set(ByVal value As Double)
            mReportWidth = value
        End Set
    End Property
 
    Private mReportHeight As Double
    Public Property ReportHeight() As Double
        Get
            Return mReportHeight
        End Get
        Set(ByVal value As Double)
            mReportHeight = value
        End Set
    End Property
 
    Public Sub New(dblWidth As Double, dblheight As Double)
        mReportHeight = dblheight
        mReportWidth = dblWidth
 
        Dim stpDashboard As New StackPanel
        mReportStackPanel.Orientation = Orientation.Vertical
        mReportStackPanel.Width = mReportWidth
        'mReportStackPanel.Height = mReportHeight
    End Sub
 
    Public Function AddElement(objObject As Object, typType As enmTypeOfControl, _
           Optional styStyle As Style = Nothing) As Integer
        Select Case typType
            Case enmTypeOfControl.usercontrol
                Dim ucUsercontrol As New UserControl
                ucUsercontrol.Margin = New Thickness(5)
                ucUsercontrol.Width = mReportWidth - 40
                ucUsercontrol.Content = objObject
                mReportStackPanel.Children.Add(ucUsercontrol)
            Case enmTypeOfControl.textBlock
                Dim txtTextBlock As New TextBlock
                txtTextBlock.Style = styStyle
                txtTextBlock.Width = mReportWidth - 40
                txtTextBlock.Text = objObject.ToString
                mReportStackPanel.Children.Add(txtTextBlock)
        End Select
        Return mReportStackPanel.Children.Count - 1
 
    End Function
 
End Class

在此类初始化时，我们创建了一个与我们实际报告必须具有的宽度和高度相同的 stackpanel。

然后我们可以使用函数 AddElement 添加元素。作为参数，我们添加一个对象（用户控件、textBlock...）、控件的类型（我们使用它进行格式化）和一个样式（可选）。它返回一个 stackpanel，然后将其添加到 ReportPage（参见上文）。

我们创建了一个 Window 来创建实际的报告

我们创建了一个窗口（可以设置为不可见）。我们必须使用一个窗口，因为所有内容都必须有时间进行渲染。在此窗口中，我们可以使用线程来等待内容渲染。

我们的窗口包含一个 docViewer，可用于预览文档。我们尝试不使用此控件，但页面没有完全渲染...

初始化报告

首先，我们使用 InitializeReport 方法初始化一个报告，该方法在窗口渲染时触发 (Me.ContentRendered)

Private dblPrtWidth As Double = 793
Private dblPrtHeight As Double = 1122
Private docRep As ReportDocument
Private docPaga as ReportPage 

Public Sub InitializeReport()
      docRep = New ReportDocument(dblPrtWidth, dblPrtHeight)
End Sub

创建页面（带有页眉、内容和页脚）

docPage = New ReportPage(dblPrtWidth, dblPrtHeight, True, True)
docPage.AddHeader(New MyHeaderUserControl)
docPage.AddFooter(DirectCast(TryFindResource("pdfFooter"), String))
docPage.AddContent(CreateContent.ReportStackPanel)
Dispatcher.Invoke(Sub() Action(), Windows.Threading.DispatcherPriority.ContextIdle, Nothing)
docRep.ReportPage.Add(docPage.CreateReportPage(True, True))
Dispatcher.Invoke(Sub() Action(), Windows.Threading.DispatcherPriority.ContextIdle, Nothing)

此块创建一个新页面，添加一个页眉（以 brkSignaletique 作为我们的一个用户控件），添加一个页脚（以一些文本作为我们的法律内容），并添加内容（窗口中的一个函数，请参见下一个代码块）。

然后，此页面被添加到 Reports (docRep)

dispatcher.invoke 调用允许代码被渲染，sub Action 只是一个空方法。

创建内容（在上面的页面中使用）

Public Function CreateContent() As ReportContent
    'CREATE PAGECONTENT
    Dim docContent As New ReportContent(dblPrtWidth, dblPrtHeight)
    Dim i As Integer

    'ADD TITLE TO PAGECONTENT
    docContent.AddElement("TITLE", _
      ReportContent.enmTypeOfControl.textBlock, FindResource("ReportTitle"))
    Dispatcher.Invoke(Sub() Action(), Windows.Threading.DispatcherPriority.ContextIdle, Nothing)

    'A USERCONTROL
    objUserControl = New MyUserControl()
    Dispatcher.Invoke(Sub() Action(), Windows.Threading.DispatcherPriority.ContextIdle, Nothing)
    'ADD TO PAGECONTENT
    i = docContent.AddElement(objUserControl , ReportContent.enmTypeOfControl.usercontrol)
    Dispatcher.Invoke(Sub() Action(), Windows.Threading.DispatcherPriority.ContextIdle, Nothing)
    'Additional actions
    DirectCast(DirectCast(docContent.ReportStackPanel.Children(i), UserControl).Content, _
      MyUserControl).imInside.Visibility = Windows.Visibility.Collapsed
    Dispatcher.Invoke(Sub() Action(), Windows.Threading.DispatcherPriority.ContextIdle, Nothing)

    'ADD SPACE TO PAGECONTENT
    docContent.AddElement("", _
      ReportContent.enmTypeOfControl.textBlock, FindResource("ReportSpacer"))
    Dispatcher.Invoke(Sub() Action(), Windows.Threading.DispatcherPriority.ContextIdle, Nothing)

    Return docContent
End Function

此函数在我们的内容中添加了 3 个内容：标题（一个 TextBlock）、我们的用户控件和一个间隔（空 textblock）。当然，您可以添加任意数量的内容，只要它适合 1 页！当我们将我们的用户控件 (MyUserControl) 添加到 docContent 时，我们获取我们的用户控件在 docContent 的 stackpanel 中的位置。这样，我们可以更改我们的用户控件，例如，隐藏报告中不需要的按钮。

完成报告

Private Sub FinalizeReport()
    'CREATE FINAL DOCUMENT
    DocViewer.Document = docRep.CreateReport()
    Dispatcher.Invoke(Sub() Action(), Windows.Threading.DispatcherPriority.ContextIdle, Nothing)
    mFile = "c:\report"       
    Dim xpsDoc As New XpsDocument(mFile & ".xps", IO.FileAccess.ReadWrite)
    Dim XpsDocWriter As Xps.XpsDocumentWriter = XpsDocument.CreateXpsDocumentWriter(xpsDoc)
    XpsDocWriter.Write(docRep.ReportDocument)
    xpsDoc.Close()
    PdfSharp.Xps.XpsConverter.Convert(mFile & ".xps", mFile & ".pdf", 0)
End Sub

我们将 docRep 添加到我们的 docviewer。如果您在那里停止，您可以预览该文档。在这里，我们添加了一些东西来创建 XPF，然后使用 PdfSharp XPS 转换器（要下载并添加到引用）将其转换为 PDF。

这就是窍门。有什么问题吗？问吧！

祝你好运，Wim