BringIntoView无法正常工作 [英] BringIntoView is not working
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问题描述
我在事件处理程序后面有以下代码：
I have this code behind event handler:
private void comboActiveStudentAssignmentType_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
List<Border> borders = new List<Border>();
// The list of border (focus rectangles) matches the combo of assignment types
borders.Add(borderBibleReadingMain);
borders.Add(borderBibleReadingClass1);
borders.Add(borderBibleReadingClass2);
borders.Add(borderMainHallStudent1);
borders.Add(borderMainHallAssistant1);
borders.Add(borderMainHallStudent2);
borders.Add(borderMainHallAssistant2);
borders.Add(borderMainHallStudent3);
borders.Add(borderMainHallAssistant3);
borders.Add(borderClass1Student1);
borders.Add(borderClass1Assistant1);
borders.Add(borderClass1Student2);
borders.Add(borderClass1Assistant2);
borders.Add(borderClass1Student3);
borders.Add(borderClass1Assistant3);
borders.Add(borderClass2Student1);
borders.Add(borderClass2Assistant1);
borders.Add(borderClass2Student2);
borders.Add(borderClass2Assistant2);
borders.Add(borderClass2Student3);
borders.Add(borderClass2Assistant3);
// Loop through the borders
for(int iBorder = 0; iBorder < borders.Count; iBorder++)
{
// Is this border the active student assignment?
if (comboActiveStudentAssignmentType.SelectedIndex == iBorder)
{
// Yes, so use a red brush for the background
borders[iBorder].BorderBrush = Brushes.Red;
// Now we must ensure the correct tab item is visible
if(iBorder >= 0 && iBorder <= 2)
{
expandTFGW.IsExpanded = true;
if (iBorder == 0)
tabTFGWReadingMainHall.IsSelected = true;
else if (iBorder == 1)
tabTFGWReadingClass1.IsSelected = true;
else if (iBorder == 2)
tabTFGWReadingClass2.IsSelected = true;
}
else if (iBorder >= 3 && iBorder <= 8)
{
expandAYFM.IsExpanded = true;
tabAYFMStudentsMainHall.IsSelected = true;
if (iBorder == 3 || iBorder == 4)
tabMainHallItem1.IsSelected = true;
else if (iBorder == 5 || iBorder == 6)
tabMainHallItem2.IsSelected = true;
else if (iBorder == 7 || iBorder == 8)
tabMainHallItem3.IsSelected = true;
}
else if (iBorder >= 9 && iBorder <= 14)
{
expandAYFM.IsExpanded = true;
tabAYFMStudentsClass1.IsSelected = true;
if (iBorder == 9 || iBorder == 10)
tabClass1Item1.IsSelected = true;
else if (iBorder == 11 || iBorder == 12)
tabClass1Item2.IsSelected = true;
else if (iBorder == 13 || iBorder == 14)
tabClass1Item3.IsSelected = true;
}
else if (iBorder >= 15)
{
expandAYFM.IsExpanded = true;
tabAYFMStudentsClass2.IsSelected = true;
if (iBorder == 15 || iBorder == 16)
tabClass2Item1.IsSelected = true;
else if (iBorder == 17 || iBorder == 18)
tabClass2Item2.IsSelected = true;
else if (iBorder == 19 || iBorder == 20)
tabClass2Item3.IsSelected = true;
}
borders[iBorder].BringIntoView();
}
else
{
// No, so set the background to transparent so we can't see it.
borders[iBorder].BorderBrush = Brushes.Transparent;
}
}
}
}
XAML中 Border 对象之一的示例：
An example of one of the Border objects in XAML:
<Border x:Uid="borderMainHallStudent1" x:Name="borderMainHallStudent1" BorderThickness="5">
<Border.Style>
<Style x:Uid="Style_30" TargetType="Border">
<Setter x:Uid="Setter_76" Property="BorderBrush" Value="Transparent"/>
<Style.Triggers>
<DataTrigger x:Uid="DataTrigger_29" Binding="{Binding SelectedItem, ElementName=comboActiveStudentAssignmentType}"
Value="{x:Static StudentInfoEnums:StudentAssignmentType.Student1Main}">
<Setter x:Uid="Setter_77" Property="BorderBrush" Value="Red"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Border.Style>
<StackPanel x:Uid="StackPanel_35">
<Label x:Uid="Label_38" Content="Student:"/>
<Grid x:Uid="Grid_15">
<Grid.ColumnDefinitions>
<ColumnDefinition x:Uid="ColumnDefinition_34" Width="*"/>
<ColumnDefinition x:Uid="ColumnDefinition_35" Width="auto"/>
</Grid.ColumnDefinitions>
<TextBox x:Uid="textMainHallStudent1" x:Name="textMainHallStudent1"
Text="{Binding MainHallStudent1, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
IsEnabled="False" Grid.Column="0" Margin="2" />
<Button x:Uid="buttonMainHallStudent1" x:Name="buttonMainHallStudent1" Grid.Column="1" Background="Transparent"
DataContext="{Binding DataContext, ElementName=oclmEditor}"
Command="{Binding ApplicationCommand}"
CommandParameter="Student1Main">
<Image x:Uid="Image_17" Source="Images/AssignmentTypeStudent16.png" Margin="2"/>
</Button>
</Grid>
<Label x:Uid="Label_39" Content="Study:"/>
<ComboBox x:Uid="ComboBox_9" DataContext="{Binding DataContext, ElementName=oclmEditor}"
ItemsSource="{Binding StudentStudyPointsList}"
ItemContainerStyle="{StaticResource StudyPointComboBoxStyle}"
ItemTemplate="{StaticResource StudyPointComboItem}"
Validation.ErrorTemplate="{StaticResource StudyPointValidationTemplate}"
Tag="{Binding Meeting.MainHallStudent1, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}"
SelectedValue="{Binding Meeting.MainHallStudent1StudyNumber, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
SelectedValuePath="Number"/>
</StackPanel>
</Border>
此行代码： borders [iBorder] .BringIntoView（）; 似乎无效。我所有Border对象的颜色都已正确设置，但是程序显然没有尝试反对这一行代码。
This line of code: borders[iBorder].BringIntoView(); It does not seem to work. The colours of all my Border objects is set correctly, but the program evidently makes no attempt to object this line of code.
为您提供边界对象存在：
\\ Main Window
\\ScrollView
\\ Expander
\\Tab Control
\\Tab Item
\\Border 1
\\Contents
\\Border 2
\\Contents
\\ Expander
\\Tab Control
\\Tab Item
\\Border 1
\\Contents
\\Border 2
\\Contents
推荐答案
BringIntoView（），根据 MSDN ：
尝试将该元素包含在其中包含的任何 scrollable 区域中。
因此它不会选择选项卡项目，展开扩展器等。您需要自己做。
Therefore it will not select tab items, expand expanders, etc. You need to do that yourself.
请注意，由于调度程序的优先级队列，您进行更改（例如选择选项卡）后，该内容可能不可用。在这种情况下，您可能想以较低的优先级发布视图请求：
Note that due to the dispatcher's priority queue, the content may not be available as soon as you make changes (such as select a tab). In that case, you may want to post the bring-into-view request in a lower priority:
var localBorderIndex = iBorder; // copy to avoid closure of loop variable
Dispatcher.InvokeAsync(() => borders[localBorderIndex].BringIntoView(),
DispatcherPriority.Background);
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