我的 WPF 应用程序中有一个搜索屏幕。屏幕实现为 TabControl 的 TabItem 中的 UserControl。当用户切换到“搜索”选项卡时，我希望焦点进入一个特定字段。我在这里问了一个关于如何确定焦点的问题。我现在知道它要去哪里了。现在我想弄清楚它为什么会去那里，这样我就可以阻止它。
请注意，焦点是自发变化的，与任何用户活动无关。用户所做的只是单击主窗口中的搜索选项卡。焦点应该转到这个特定的文本框；这是在 UserControl 的 Loaded 事件处理程序中完成的。它最初确实转到了那个 TextBox。然后，由于某种原因，它转到 CheckBox。
我已经为表单上的 TabIndex 控件分配了值，用户可以与之交互。CheckBox 位于 TabIndex 1。有问题的 TextBox 位于 TabIndex 9。这也是表单上唯一的 TextBox。
过去，焦点会移动到 TextBox 并停留在那里。不知不觉中，我更改了一些导致焦点转到 CheckBox 的内容。我不知道我改变了什么，除了大约是在我将 Telerik 控件库升级到最新版本的时候。
这是整个控件的 Xaml，减去一些无关紧要的东西：
<UserControl x:Class="CarSystem.CustomControls.Searcher"
<!-- XML Namespaces removed for brevity -->
Height="620"
Loaded="UserControl_Loaded"
Width="990">
<UserControl.Resources>
<!--- Resource removed for brevity -->
</UserControl.Resources>
<Grid Background="{DynamicResource ContentBackground}"
FocusManager.IsFocusScope="True"
Name="LayoutRoot">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="110" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid Grid.Column="0"
Grid.Row="0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<GroupBox BorderBrush="{DynamicResource ControlBorder}"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Column="0"
Grid.Row="0"
Header="Alarm Class:"
Margin="5,0">
<Grid VerticalAlignment="Center">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="35" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<CheckBox Click="AllAlarmClasses_Click"
Content="ALL"
FontSize="14"
FontWeight="Bold"
Grid.Column="0"
Grid.Row="0"
HorizontalAlignment="Left"
Margin="5"
Name="AllAlarmClasses"
TabIndex="1"
VerticalAlignment="Center" />
<Button Background="{DynamicResource ButtonBackground}"
Click="ExpandPicker_Click"
Content="Expand"
FontSize="14"
FontWeight="Bold"
Grid.Column="1"
Grid.Row="0"
Foreground="{DynamicResource ButtonForeground}"
Margin="5"
Name="ExpandAlarmClass"
TabIndex="2" />
<ListBox BorderBrush="Black"
BorderThickness="1"
CheckBox.Click="AlarmClassPicker_Click"
ItemTemplate="{StaticResource CheckableChoice}"
FontSize="14"
FontWeight="Bold"
Grid.Column="0"
Grid.ColumnSpan="2"
Grid.Row="1"
Height="100"
ItemsSource="{Binding Path=AlarmClassChoices, RelativeSource={RelativeSource AncestorType={x:Type UserControl}}, Mode=TwoWay}"
Margin="5,0"
Name="AlarmClassPicker"
SelectionMode="Multiple"
TabIndex="3"
Visibility="Collapsed" />
</Grid>
</GroupBox>
<GroupBox BorderBrush="{DynamicResource ControlBorder}"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Column="0"
Grid.Row="1"
Header="Source:"
Margin="5,0">
<cs:TouchComboBox Background="{DynamicResource UnfocusedBackground}"
BorderBrush="{DynamicResource ControlBorder}"
FontSize="14"
FontWeight="Bold"
Foreground="{DynamicResource UnfocusedForeground}"
GridBackground="{DynamicResource ContentBackground}"
Height="50"
IsTabStop="True"
ItemsSource="{Binding Path=HotListChoices, RelativeSource={RelativeSource AncestorType={x:Type UserControl}}, Mode=TwoWay}"
Margin="5,0"
x:Name="HotListPicker"
SelectionChanged="SourcePicker_SelectionChanged"
TabIndex="4"
TimeOfDayMode="{Binding Path=TimeOfDayMode, RelativeSource={RelativeSource AncestorType={x:Type cs:Searcher}}}"
VerticalAlignment="Top" />
</GroupBox>
<GroupBox BorderBrush="{DynamicResource ControlBorder}"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Column="1"
Grid.Row="0"
Header="Start Date:"
Margin="5,0">
<telerik:RadDateTimePicker FontWeight="Bold"
Height="35"
Margin="5"
Name="StartDatePicker"
SelectionChanged="DateTimePicker_SelectionChanged"
Style="{DynamicResource RadDateTimePickerControlTemplate1}"
TabIndex="5"
VerticalAlignment="Center" />
</GroupBox>
<GroupBox BorderBrush="{DynamicResource ControlBorder}"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Column="1"
Grid.Row="1"
Header="End Date:"
Margin="5,0">
<telerik:RadDateTimePicker FontSize="14"
FontWeight="Bold"
Height="35"
Margin="5"
Name="EndDatePicker"
SelectionChanged="DateTimePicker_SelectionChanged"
Style="{DynamicResource RadDateTimePickerControlTemplate1}"
TabIndex="6"
VerticalAlignment="Center" />
</GroupBox>
<GroupBox BorderBrush="{DynamicResource ControlBorder}"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Column="2"
Grid.Row="0"
Header="State:"
Margin="5,0">
<cs:TouchComboBox Background="{DynamicResource UnfocusedBackground}"
BorderBrush="{DynamicResource ControlBorder}"
DisplayMemberPath="Value"
FontSize="14"
FontWeight="Bold"
Foreground="{DynamicResource UnfocusedForeground}"
GridBackground="{DynamicResource ContentBackground}"
Height="50"
ItemsSource="{Binding Path=LocaleChoices, Mode=TwoWay, RelativeSource={RelativeSource AncestorType={x:Type UserControl}}}"
Margin="5"
x:Name="StatePicker"
SelectedValue="{Binding Path=LocaleCode}"
SelectedValuePath="Key"
SelectionChanged="StatePicker_SelectionChanged"
TabIndex="7"
TimeOfDayMode="{Binding Path=TimeOfDayMode, RelativeSource={RelativeSource AncestorType={x:Type cs:Searcher}}}"
VerticalAlignment="Center" />
</GroupBox>
<GroupBox BorderBrush="{DynamicResource ControlBorder}"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Column="2"
Grid.Row="1"
Header="Plate:"
Margin="5,0">
<Border BorderBrush="{DynamicResource ControlBorder}"
BorderThickness="1"
Height="35"
Margin="5"
VerticalAlignment="Center">
<TextBox FontSize="14"
FontWeight="Bold"
GotFocus="PlateBox_GotFocus"
LostFocus="PlateBox_LostFocus"
Margin="-1"
MaxLength="25"
MaxLines="1"
Name="PlateBox"
TabIndex="8"
Text="{Binding Path=Plate, Mode=TwoWay}"
TextChanged="PlateBox_TextChanged"
ToolTip='Wildcards ("%", "_", "[", "]") can be used' />
</Border>
</GroupBox>
</Grid>
<TabControl Background="{DynamicResource TabBackground}"
Grid.Row="1"
Margin="0,20,0,5"
Name="ResultTabs"
TabIndex="9">
<TabItem Background="{DynamicResource TabHeaderBackground}"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TabHeaderForeground}"
Header="Hot List Entries:"
Name="HotListEntryTab">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<telerik:RadGridView AutoExpandGroups="True"
AutoGenerateColumns="False"
CanUserDeleteRows="False"
CanUserFreezeColumns="False"
CanUserInsertRows="False"
CanUserResizeColumns="True"
CanUserSortColumns="True"
EnableColumnVirtualization="True"
EnableRowVirtualization="True"
FontSize="14"
FontWeight="Bold"
IsReadOnly="True"
Name="HotListEntriesGrid"
SelectionChanged="HotListEntriesGrid_SelectionChanged"
SelectionUnit="FullRow"
ScrollViewer.CanContentScroll="True"
ScrollViewer.HorizontalScrollBarVisibility="Auto"
ScrollViewer.VerticalScrollBarVisibility="Auto"
TabIndex="10"
ToolTip="Matching Hot List Entries">
<telerik:RadGridView.Columns>
<telerik:GridViewDataColumn DataMemberBinding="{Binding Plate, Mode=OneWay}"
Header="Plate"
Width="*" />
<telerik:GridViewDataColumn DataMemberBinding="{Binding LocaleCode, Mode=OneWay}"
Header="State"
Width="75" />
<telerik:GridViewDataColumn DataMemberBinding="{Binding ListName, Mode=OneWay}"
Header="Source"
Width="150" />
<telerik:GridViewDataColumn DataMemberBinding="{Binding AlarmClass, Mode=OneWay}"
Header="Alarm Class"
Width="150" />
<telerik:GridViewDataColumn DataMemberBinding="{Binding Notes, Mode=OneWay}"
Header="Notes"
Width="*" />
</telerik:RadGridView.Columns>
</telerik:RadGridView>
<cs:ProgressControl FontSize="14"
FontWeight="Bold"
Grid.Column="0"
Grid.Row="1"
Height="55"
Margin="0,5"
x:Name="HotListProgressCtrl"
TabIndex="11"
TimeOfDayMode="{Binding Path=TimeOfDayMode, RelativeSource={RelativeSource AncestorType={x:Type cs:Searcher}}}"
Visibility="Collapsed" />
</Grid>
</TabItem>
<TabItem Background="{DynamicResource TabHeaderBackground}"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TabHeaderForeground}"
Header="Reads & Alarms:"
IsSelected="True"
Name="ReadsTabItem">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<telerik:RadGridView AutoExpandGroups="True"
AutoGenerateColumns="False"
CanUserDeleteRows="False"
CanUserFreezeColumns="False"
CanUserInsertRows="False"
CanUserResizeColumns="True"
CanUserSortColumns="True"
EnableColumnVirtualization="True"
EnableRowVirtualization="True"
FontSize="14"
FontWeight="Bold"
IsReadOnly="True"
Name="ReadsGrid"
RowDetailsTemplate="{StaticResource ReadRowDetailsTemplate}"
RowStyleSelector="{StaticResource StyleSelector}"
SelectionChanged="ReadsGrid_SelectionChanged"
SelectionUnit="FullRow"
ScrollViewer.CanContentScroll="True"
ScrollViewer.HorizontalScrollBarVisibility="Auto"
ScrollViewer.VerticalScrollBarVisibility="Auto"
ShowGroupFooters="True"
TabIndex="12"
ToolTip="Matching Reads">
<telerik:RadGridView.Columns>
<cs:CustomGridViewToggleRowDetailsColumn IsEnabled="False"
IsFilterable="False"
IsGroupable="False"
ToggleButtonVisibility="{Binding Path=HasAlarms, Converter={StaticResource BoolToVisibility}}" />
<telerik:GridViewDataColumn DataMemberBinding="{Binding Plate, Mode=OneWay}"
Header="Plate"
Width="*" />
<telerik:GridViewDataColumn DataMemberBinding="{Binding State, Mode=OneWay}"
Header="State"
Width="75" />
<telerik:GridViewDataColumn DataMemberBinding="{Binding TimeStamp, Mode=OneWay, Converter={StaticResource DateConverter}}"
Header="Date & Time"
Width="150" />
<telerik:GridViewDataColumn DataMemberBinding="{Binding Latitude, Converter={StaticResource CoordConverter}, ConverterParameter=NS}"
Header="Latitude"
Width="150" />
<telerik:GridViewDataColumn DataMemberBinding="{Binding Longitude, Converter={StaticResource CoordConverter}, ConverterParameter=EW}"
Header="Longitude"
Width="150" />
</telerik:RadGridView.Columns>
</telerik:RadGridView>
<cs:ProgressControl FontSize="14"
FontWeight="Bold"
Grid.Row="1"
Height="55"
Margin="0,5"
x:Name="ProgressCtrl"
TabIndex="13"
TimeOfDayMode="{Binding Path=TimeOfDayMode, RelativeSource={RelativeSource AncestorType={x:Type cs:Searcher}}}"
Visibility="Collapsed" />
</Grid>
</TabItem>
</TabControl>
<GridSplitter Background="{DynamicResource SeparatorColor}"
Grid.Row="1"
Height="10"
HorizontalAlignment="Stretch"
Margin="0,5"
VerticalAlignment="Top" />
<Grid Grid.Column="1"
Grid.RowSpan="2">
<Grid.RowDefinitions>
<RowDefinition Height="55" />
<RowDefinition Height="55" />
<RowDefinition Height="55" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="55" />
<RowDefinition Height="55" />
</Grid.RowDefinitions>
<Button Background="{DynamicResource ButtonBackground}"
Click="SearchButton_Click"
Content="Search"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource ButtonForeground}"
Grid.Row="0"
IsDefault="True"
Margin="5"
Name="SearchButton"
TabIndex="14" />
<Button Background="{DynamicResource ButtonBackground}"
Click="ClearButton_Click"
Content="Clear"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource ButtonForeground}"
Grid.Row="1"
Margin="5"
Name="ClearButton"
TabIndex="15" />
<Button Background="{DynamicResource ButtonBackground}"
Click="SaveCriteriaButton_Click"
FontSize="16"
FontWeight="Bold"
Grid.Row="2"
Foreground="{DynamicResource ButtonForeground}"
Margin="5"
Name="SaveCriteriaButton"
TabIndex="16"
Visibility="Visible">
<Button.Content>
<TextBlock Text="Save Report"
TextAlignment="Center"
TextWrapping="Wrap" />
</Button.Content>
</Button>
<TextBlock FontSize="14"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Row="4"
Margin="5"
Text="Number of Matches:"
TextAlignment="Center"
TextWrapping="Wrap" />
<TextBlock FontSize="14"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Row="5"
Margin="5"
Text="Hot List Entries:"
TextAlignment="Center"
TextWrapping="Wrap" />
<TextBlock FontSize="14"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Row="6"
Margin="5,0,5,10"
Text="{Binding Converter={StaticResource LongConverter}, ConverterParameter='#,##0', Path=NoHotListEntries, RelativeSource={RelativeSource AncestorType={x:Type cs:Searcher}}}"
TextAlignment="Center"
TextWrapping="Wrap" />
<TextBlock FontSize="14"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Row="7"
Margin="5"
Text="Reads:"
TextAlignment="Center"
TextWrapping="Wrap" />
<TextBlock FontSize="14"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Row="8"
Margin="5,0,5,10"
Text="{Binding Converter={StaticResource LongConverter}, ConverterParameter='#,##0', Path=NoReads, RelativeSource={RelativeSource AncestorType={x:Type cs:Searcher}}}"
TextAlignment="Center"
TextWrapping="Wrap" />
<Button Background="{DynamicResource ButtonBackground}"
Click="ExportButton_Click"
Content="Export"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource ButtonForeground}"
Grid.Row="10"
Margin="5"
Name="ExportButton"
TabIndex="17" />
<Button Background="{DynamicResource ButtonBackground}"
Click="CloseButtonClicked"
Content="Close"
FontSize="20"
FontWeight="Bold"
Foreground="{DynamicResource ButtonForeground}"
Grid.Row="11"
HorizontalAlignment="Right"
Margin="5"
Name="CloseButton"
TabIndex="18"
Width="100" />
</Grid>
<Canvas Grid.Column="0"
Grid.ColumnSpan="2"
Grid.Row="0"
Grid.RowSpan="4"
Name="KeyboardPopupCanvas">
<cs:KeyboardPopup x:Name="KeyboardPopup"
TimeOfDayMode="{Binding Path=TimeOfDayMode, RelativeSource={RelativeSource AncestorType={x:Type cs:Searcher}}}"
Title="Keyboard"
Visibility="Collapsed" />
</Canvas>
</Grid>
谢谢你的帮助
托尼