Question

我需要帮助才能访问例如。来自代码的TextBox。我使用VB但C＃示例也很受欢迎。如果我尝试通过键入txtSettingsCity来访问TextBox，则VB无法识别TextBox。

我非常感激。提前谢谢。

            <Button x:Name="btnSettings" FontSize="16" FontFamily="Segoe MDL2 Assets" Content="&#xE115;" Foreground="{StaticResource NuhmeTextColor}" RelativePanel.AlignLeftWithPanel="True" RelativePanel.AlignBottomWithPanel="True" Margin="4,0,0,4">
            <Button.Flyout>
                <MenuFlyout x:Name="mfSettings">
                    <MenuFlyoutItem x:Name="mfiSettings">
                        <MenuFlyoutItem.Template>
                            <ControlTemplate TargetType="MenuFlyoutItem">
                                <StackPanel Margin="4,10,4,0" Orientation="Vertical" Width="130">
                                    <TextBox x:Name="txtSettingsCity" Header="Din placering" PlaceholderText="Ribe, Danmark" Width="130" Margin="0,0,0,10" ToolTipService.ToolTip="Indtast din placering eller klik søg"/>
                                    <Button x:Name="btnFindLocation" Content="Søg" Margin="80,0,0,10" Click="btnFindLocation_Click"/>

                                </StackPanel>
                            </ControlTemplate>
                        </MenuFlyoutItem.Template>
                    </MenuFlyoutItem>
                </MenuFlyout>
            </Button.Flyout>
        </Button>

Answer 1

您可以循环浏览VisualTreeHelper.GetParent以首先获取父MenuFlyoutItem，然后递归使用VisualTreeHelper.GetChild返回TextBox。

但是，我强烈建议您探索MVVM方法并将Button.Command绑定到ICommand并将TextBox绑定作为Button.CommandParameter传递。

快速而肮脏的例子

private void btnFindLocation_OnClick(object sender, RoutedEventArgs e)
{
    var target = sender as DependencyObject;

    while (target != null)
    {
        target = VisualTreeHelper.GetParent(target);

        if (target is MenuFlyoutItem menuFlyoutItem)
        {
            if (GetChild<TextBox>(menuFlyoutItem) is TextBox textBox)
            {
                // Access the TextBox here
                Debug.WriteLine(textBox.Text);
            }
        }
    }
}

private TFrameworkElement GetChild<TFrameworkElement>(FrameworkElement parent) where TFrameworkElement : FrameworkElement
{
    var count = VisualTreeHelper.GetChildrenCount(parent);

    for (var index = 0; index < count; ++index)
    {
        var child = VisualTreeHelper.GetChild(parent, index) as FrameworkElement;

        if (child is TFrameworkElement frameworkElement)
        {
            return frameworkElement;
        }
        else
        {
            if (GetChild<TFrameworkElement>(child) is TFrameworkElement grandChild)
            {
                return grandChild;
            }
        }
    }

    return null;
}

Answer 2

为什么不使用VisualTreeHelprer，这是一个快速的代码示例;

  Public Shared Function FindParent(Of T As DependencyObject)(ByVal child As DependencyObject) As T
    Dim parentObject As DependencyObject = VisualTreeHelper.GetParent(child)
    If parentObject Is Nothing Then Return Nothing
    Dim parent As T = TryCast(parentObject, T)
    If parent IsNot Nothing Then Return parent Else Return FindParent(Of T)(parentObject)
End Function

该功能的用法：

  Dim parent As ControlTypeHere= FindParent(Of ControlTypeHere)(Me)

如何从VB / C＃代码

2 个答案: