我在TextBox的工具栏中创建了一个DocumentViewer控件，用于显示当前页面编号。并为用户提供GoTo类型设施。
以下是代码：
<Style x:Key="DocumentViewerStyle1" BasedOn="{x:Null}" TargetType="{x:Type DocumentViewer}">
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/>
<Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/>
<Setter Property="FocusVisualStyle" Value="{x:Null}"/>
<Setter Property="ContextMenu" Value="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerContextMenu, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DocumentViewer}">
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Focusable="False">
<Grid Background="{TemplateBinding Background}" KeyboardNavigation.TabNavigation="Local">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<ContentControl Grid.Column="0" Focusable="{TemplateBinding Focusable}" Grid.Row="0" Style="{DynamicResource ContentControlStyle1}" TabIndex="0"/>
<ScrollViewer x:Name="PART_ContentHost" CanContentScroll="true" Grid.Column="0" Focusable="{TemplateBinding Focusable}" HorizontalScrollBarVisibility="Auto" IsTabStop="true" Grid.Row="1" TabIndex="1"/>
<DockPanel Grid.Row="1">
<FrameworkElement DockPanel.Dock="Right" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}"/>
<Rectangle Height="10" Visibility="Visible" VerticalAlignment="top">
<Rectangle.Fill>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<LinearGradientBrush.GradientStops>
<GradientStopCollection>
<GradientStop Color="#66000000" Offset="0"/>
<GradientStop Color="Transparent" Offset="1"/>
</GradientStopCollection>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
<!--<Image Grid.Column="0" Grid.Row="2" Width="100"/>-->
</DockPanel>
<!--<TextBlock Grid.Row="2" Grid.Column="0" x:Name="txtBlock" Text="Hello World"/>-->
<ContentControl x:Name="PART_FindToolBarHost" Grid.Column="0" Focusable="{TemplateBinding Focusable}" Grid.Row="2" TabIndex="2"/>
<TextBlock Text="Aspire Education" Grid.Row="2" Grid.Column="0" Margin="300,0,0,0" Foreground="#FF0758DC" FontSize="18" />
</Grid>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="ContentControlStyle1" TargetType="{x:Type ContentControl}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ContentControl}">
<ToolBar Focusable="{TemplateBinding Focusable}" ToolBarTray.IsLocked="True" Language="en-us" KeyboardNavigation.TabNavigation="Continue" Uid="ToolBar_2">
<Button x:Name="PrintButton" Background="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerPrintButton, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" CommandTarget="{Binding TemplatedParent, RelativeSource={RelativeSource TemplatedParent}}" Command="ApplicationCommands.Print" IsTabStop="True" Margin="2" Padding="2" Style="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerButtonStyle, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" ToolTipService.ShowOnDisabled="True" TabIndex="0" ToolTip="Print (Ctrl+P)" Uid="Button_14" VerticalAlignment="Center" Width="24"/>
<Button x:Name="CopyButton" Background="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerCopyButton, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" CommandTarget="{Binding TemplatedParent, RelativeSource={RelativeSource TemplatedParent}}" Command="ApplicationCommands.Copy" IsTabStop="True" Margin="2" Padding="2" Style="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerButtonStyle, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" ToolTipService.ShowOnDisabled="True" TabIndex="1" ToolTip="Copy (Ctrl+C)" Uid="Button_15" VerticalAlignment="Center" Width="24"/>
<Separator Uid="Separator_110"/>
<Button x:Name="ZoomInButton" Background="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerZoomInButton, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" CommandTarget="{Binding TemplatedParent, RelativeSource={RelativeSource TemplatedParent}}" Command="NavigationCommands.IncreaseZoom" IsTabStop="True" Margin="2" Padding="2" Style="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerButtonStyle, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" ToolTipService.ShowOnDisabled="True" TabIndex="3" ToolTip="Increase the size of the content (Ctrl +)" Uid="Button_16" VerticalAlignment="Center" Width="24"/>
<Button x:Name="ZoomOutButton" Background="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerZoomOutButton, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" CommandTarget="{Binding TemplatedParent, RelativeSource={RelativeSource TemplatedParent}}" Command="NavigationCommands.DecreaseZoom" IsTabStop="True" Margin="2" Padding="2" Style="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerButtonStyle, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" ToolTipService.ShowOnDisabled="True" TabIndex="4" ToolTip="Decrease the size of the content (Ctrl -)" Uid="Button_17" VerticalAlignment="Center" Width="24"/>
<Separator Uid="Separator_111"/>
<Button x:Name="ActualSizeButton" Background="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerActualSizeButton, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" CommandTarget="{Binding TemplatedParent, RelativeSource={RelativeSource TemplatedParent}}" CommandParameter="100.0" Command="NavigationCommands.Zoom" IsTabStop="True" Margin="2" Padding="2" Style="{DynamicResource ButtonStyle1}" ToolTipService.ShowOnDisabled="True" TabIndex="5" ToolTip="100% (Ctrl+1)" Uid="Button_18" VerticalAlignment="Center" Width="24"/>
<Button x:Name="PageWidthButton" Background="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerPageWidthButton, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" CommandTarget="{Binding TemplatedParent, RelativeSource={RelativeSource TemplatedParent}}" Command="DocumentViewer.FitToWidthCommand" IsTabStop="True" Margin="2" Padding="2" Style="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerButtonStyle, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" ToolTipService.ShowOnDisabled="True" TabIndex="6" ToolTip="Page Width (Ctrl+2)" Uid="Button_19" VerticalAlignment="Center" Width="24"/>
<Button x:Name="WholePageButton" Background="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerWholePageButton, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" CommandTarget="{Binding TemplatedParent, RelativeSource={RelativeSource TemplatedParent}}" CommandParameter="1" Command="DocumentViewer.FitToMaxPagesAcrossCommand" IsTabStop="True" Margin="2" Padding="2" Style="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerButtonStyle, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" ToolTipService.ShowOnDisabled="True" TabIndex="7" ToolTip="Whole Page (Ctrl+3)" Uid="Button_20" VerticalAlignment="Center" Width="24"/>
<Button x:Name="TwoPagesButton" Background="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerTwoPagesButton, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" CommandTarget="{Binding TemplatedParent, RelativeSource={RelativeSource TemplatedParent}}" CommandParameter="2" Command="DocumentViewer.FitToMaxPagesAcrossCommand" IsTabStop="True" Margin="2" Padding="2" Style="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerButtonStyle, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}" ToolTipService.ShowOnDisabled="True" TabIndex="8" ToolTip="Two Pages (Ctrl+4)" Uid="Button_21" VerticalAlignment="Center" Width="24"/>
<Separator Uid="Separator_112"/>
<TextBox x:Name="txtCurrentPage" Text="580" Width="30" BorderBrush="Black" TextChanged="txtCurrentPage_TextChanged"></TextBox>
<TextBox x:Name="txtTotalPage" Text="/250" Width="40" IsReadOnly="True" BorderBrush="Black" Foreground="Black"></TextBox>
</ToolBar>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
但是当我试图访问该文本框时，它显示为null。
这是我背后的代码。
private void txtCurrentPage_TextChanged(object sender, TextChangedEventArgs e)
{
MainWindow mn = new MainWindow();
TextBox tb = (TextBox)mn.FindName("txtCurrentPage");
if (tb != null)
{
DocumentViewerReading.GoToPage(Convert.ToInt32(tb.Text));
}
}
请帮助
答案 0 :(得分：2)
您不需要再次找到控件，它的引用应该在sender参数中。
private void txtCurrentPage_TextChanged(object sender, TextChangedEventArgs e)
{
TextBox tb = (TextBox)sender;
if (tb != null)
{
DocumentViewerReading.GoToPage(Convert.ToInt32(tb.Text));
}
}
每当文本框的内容发生变化并尝试在该新窗口中查找文本框时，您正在创建一个窗口的新实例，这不是它应该如何工作，您已经有了一个实例用户在其上键入的窗口。
答案 1 :(得分：-1)
以下是完整的解决方案： -
<Style x:Key="DocumentViewerStyle1" BasedOn="{x:Null}" TargetType="{x:Type DocumentViewer}">
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/>
<Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/>
<Setter Property="FocusVisualStyle" Value="{x:Null}"/>
<Setter Property="ContextMenu" Value="{DynamicResource {ComponentResourceKey ResourceId=PUIDocumentViewerContextMenu, TypeInTargetAssembly={x:Type System_Windows_Documents:PresentationUIStyleResources}}}"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DocumentViewer}">
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Focusable="False">
<Grid x:Name="grdDocumentViewer" Background="{TemplateBinding Background}" KeyboardNavigation.TabNavigation="Local">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<ContentControl Grid.Column="0" Focusable="{TemplateBinding Focusable}" Grid.Row="0" Style="{DynamicResource ContentControlStyle1}" TabIndex="0"/>
<ScrollViewer x:Name="PART_ContentHost" CanContentScroll="true" Grid.Column="0" Focusable="{TemplateBinding Focusable}" HorizontalScrollBarVisibility="Auto" IsTabStop="true" Grid.Row="1" TabIndex="1"/>
<DockPanel Grid.Row="1">
<FrameworkElement DockPanel.Dock="Right" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}"/>
<Rectangle Height="10" Visibility="Visible" VerticalAlignment="top">
<Rectangle.Fill>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<LinearGradientBrush.GradientStops>
<GradientStopCollection>
<GradientStop Color="#66000000" Offset="0"/>
<GradientStop Color="Transparent" Offset="1"/>
</GradientStopCollection>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
<!--<Image Grid.Column="0" Grid.Row="2" Width="100"/>-->
</DockPanel>
<!--<TextBlock Grid.Row="2" Grid.Column="0" x:Name="txtBlock" Text="Hello World"/>-->
<ContentControl x:Name="PART_FindToolBarHost" Grid.Column="0" Focusable="{TemplateBinding Focusable}" HorizontalAlignment="Right" Margin="0,0,20,0" Grid.Row="0" TabIndex="2"/>
<TextBlock x:Name="tbTopicName" Text="" Grid.Row="0" Grid.Column="0" HorizontalAlignment="Center" Margin="0,2,0,0" Foreground="#FF0758DC" FontSize="20" />
</Grid>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
// 以下是Code Behind
Grid gMain = (Grid)DocumentViewerReading.Template.FindName("grdDocumentViewer", DocumentViewerReading);
TextBlock tb = (TextBlock)gMain.FindName("tbTopicName");
tb.Text = header;
就是这样。 谢谢安迪。