Question

我需要允许用户垂直调整用户控件的大小。所以搜索引导我了解了如何使用Thumb类和模板的一些示例。所以我设置了模板：

<UserControl.Resources>

    <!-- ResizeDecorator Template -->
    <ControlTemplate x:Key="ResizeDecoratorTemplate" TargetType="{x:Type Control}">
        <Grid>
            <t:ResizeThumb Height="3" Cursor="ScrollNS" VerticalAlignment="Bottom" Margin="0 0 0 -4" ItemResizeCompleted="ResizeThumb_ItemResizeCompleted" />
        </Grid>
    </ControlTemplate>

    <!-- Designer Item Template-->
    <ControlTemplate x:Key="DesignerItemTemplate" TargetType="ContentControl">
        <Grid DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
            <Control Template="{StaticResource ResizeDecoratorTemplate}" />
            <ContentPresenter Content="{TemplateBinding ContentControl.Content}" />
        </Grid>
    </ControlTemplate>

</UserControl.Resources>

然后我设置了ResizeThumb类：

Public Class ResizeThumb
Inherits Thumb

Public Event ItemResizeCompleted(sender As Object, e As TimeSlotPanelItemResizeEventArgs)
Public Property id As Integer

Public Sub New()
    AddHandler DragDelta, AddressOf ResizeThumb_DragDelta
End Sub

Private Sub ResizeThumb_DragDelta(sender As Object, e As DragDeltaEventArgs)
    e.Handled = True
End Sub

Private Sub ItemResized(sender As Object, e As DragCompletedEventArgs) Handles Me.DragCompleted
    Dim rs As ResizeThumb = CType(sender, ResizeThumb)
    Dim gd As Grid = CType(rs.Parent, Grid)

    Dim ee As New TimeSlotPanelItemResizeEventArgs
    ee.id = id
    ee.ResizeValue = e.VerticalChange
    RaiseEvent ItemResizeCompleted(Me, ee)
End Sub
End Class

我的UserControls是动态添加的，所以我在运行时添加模板：

    Dim si As New SchedItem(id, StartTime, Duration, SO, Title, UnitOfWork, BackgroundColor, Status, LastNote, Miles, Hours)
    Dim cc As ContentControl = New ContentControl
    cc.Content = si
    cc.Template = FindResource("DesignerItemTemplate")

每个SchedItem都有一个id。由于ResizeThumb类有一个DragComplete事件，我提出一个事件来传回VerticalChange，我想传递调整大小的SchedItem的id。我尝试将它绑定到TemplatedParent但是不允许。 ResizeThumb唯一的父级是Grid。我尝试将网格的Tag绑定到TemplatedParent，但标签中没有任何内容。

所以现在我要问;有没有办法从ResizeThumb类的ItemResized事件处理程序访问SchedItem的id属性？如果是这样，怎么样？如果没有，替代方案？

Answer 1

圣牛！我想到了。我花了大部分时间，但它终于有效了。只需要弄清楚要使用的正确绑定。所以在我的代码中，我将ContentControl的Tag设置为id。

    Dim cc As ContentControl = New ContentControl
    cc.Tag = id  '<-- right here
    cc.Content = si
    cc.Template = FindResource("DesignerItemTemplate")

然后在XAML中，弄清楚如何将该标记绑定到包含ResizeThumb类的Tag属性的Grid。

    <!-- ResizeDecorator Template -->
    <ControlTemplate x:Key="ResizeDecoratorTemplate" TargetType="{x:Type Control}">
        <Grid Tag="{Binding RelativeSource={RelativeSource AncestorType=ContentControl}, Path=Tag}">
            <t:ResizeThumb Height="3" Cursor="ScrollNS" VerticalAlignment="Bottom" Margin="0 0 0 -4" ItemResizeCompleted="ResizeThumb_ItemResizeCompleted" />
        </Grid>
    </ControlTemplate>

现在在ItemResized事件中，我可以访问网格，它是发件人的父级，并将标记分配给事件的ID。

Private Sub ItemResized(sender As Object, e As DragCompletedEventArgs) Handles Me.DragCompleted
    Dim rs As ResizeThumb = CType(sender, ResizeThumb)
    Dim gd As Grid = CType(rs.Parent, Grid)

    Dim ee As New TimeSlotPanelItemResizeEventArgs
    ee.id = gd.Tag
    ee.ResizeValue = e.VerticalChange
    RaiseEvent ItemResizeCompleted(Me, ee)
End Sub

现在我在活动中获得了身份证明。

WPF：如何从模板引发的事件中获取控件的属性值

1 个答案: