Question

我有自定义组合框和自定义箭头。如何通过代码访问此箭头并更改其大小（或使其不可见）x：Name =“Arrow”;

我尝试使用Product_CombBox.FindName（“箭头”），但它不起作用，所以我该怎么做？

<ControlTemplate x:Key="ComboBoxToggleButton" TargetType="ToggleButton">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition />
        </Grid.ColumnDefinitions>
        <VisualStateManager.VisualStateGroups>
            <VisualStateGroup x:Name="CommonStates">
                <VisualState x:Name="Normal"/>
                <VisualState x:Name="MouseOver"/>
                <VisualState x:Name="Pressed"/>
                <VisualState x:Name="Disabled"/>
            </VisualStateGroup>
        </VisualStateManager.VisualStateGroups>
        <Border x:Name="Border" SnapsToDevicePixels="True" Background="White" BorderBrush="Black" CornerRadius="15" BorderThickness="1"  />
        <Border x:Name="Border2" SnapsToDevicePixels="True" Background="White" BorderBrush="Black" CornerRadius="15" BorderThickness="1" />
        <Path x:Name="Arrow" Data="M 0 0 L 8 12 L 16 0 Z" Fill="Black" Margin="0,0,10,0" HorizontalAlignment="Right" VerticalAlignment="Center" />
    </Grid>
    <ControlTemplate.Triggers>
        <Trigger Property="ToggleButton.IsMouseOver" Value="true">
        </Trigger>

        <Trigger Property="ToggleButton.IsChecked" Value="true">
        </Trigger>
        <!-- <Trigger Property="IsEnabled" Value="False">
            <Setter Property="Foreground" Value="{StaticResource ForegroundDisabledBrush}" />
        </Trigger> -->
        <DataTrigger Binding="{Binding IsKeyboardFocusWithin, RelativeSource={RelativeSource Mode=TemplatedParent}, Mode=TwoWay}" Value="True">
        </DataTrigger >
    </ControlTemplate.Triggers>
</ControlTemplate>

Answer 1

如果ToggleButton属于Template较大ComboBox的一部分，那么您需要先找到ToggleButton，然后找到Path。为此，你需要给ToggleButton一些名字，让我们说x:Name="ToggleButton"然后：

var button = myComboBox.Template.FindName("ToggleButton", myComboBox) as ToggleButton;
var path = button.Template.FindName("Arrow", button) as System.Windows.Shapes.Path;

Answer 2

尝试使用 FindVisualChild<T> 功能，如下所示：

private void ChangePath_Click(object sender, RoutedEventArgs e)
{
    Path myPath = FindVisualChild<Path>(MyComboBox, "Arrow");

    // For example, change fill color
    if (myPath != null)
        myPath.Fill = Brushes.Red;
}

private childItem FindVisualChild<childItem>(FrameworkElement obj, string elementName) where childItem : FrameworkElement
{
    if (obj != null)
    {
        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
        {
            var child = VisualTreeHelper.GetChild(obj, i);

            if (child != null && child is childItem && (child as childItem).Name == elementName)
                return child as childItem;
            else
            {
                childItem childOfChild = FindVisualChild<childItem>(child as FrameworkElement, elementName);

                if (childOfChild != null)
                    return childOfChild;
            }
        }
    }

    return null;
}

但这不是在WPF中使用UI的最佳方式。您必须使用样式的强大功能：触发器，DataTriggers，附加行为，以便使用UI正确方便地工作。

你必须坚持一条规则：View上的任何一方：改变颜色，大小等应该在View边进行。及时将增长逻辑和代码正在悄悄地变成意大利面条代码。因此，进一步的工作和改变逻辑将是困难的。

按代码更改XAML属性

2 个答案: