引用Windows 8.1项目中xaml.cs文件中的xaml元素

Question

Hello I am currently learning Windows 8.1 development with Visual Studio 2015.
How can I refer to a xaml element in a .xaml file from the associated .xaml.cs file .

MainPage.xaml file:

<Page
x:Class="project.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:project"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">

        <HubSection Width="600" x:Uid="Section1Header" Header="Map">
        <DataTemplate>
            <Grid>
                <Button x:Name="mapButton" Content="Find my location"/>
            </Grid>
        </DataTemplate>
    </HubSection>
//...

MainPage.xaml.cs file:

namespace project
{
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
            mapButton.Click += mapButton_Click;
        }
}

On mapButton I get the error : The name 'mapButton' doesn't exist in the actual context.
I thought x:Name was a way to give a name with wich I can access the xaml element from the .xaml.cs file.

Answer 1

The problem here is that you are trying to access the name of a button from a generated content. mapButton is not in the scope of the Page but in the scope of HubSection . What you really have to do, if you want to access the button element is to use the VisualTreeHelper to get the button at runtime.

Here is an example.

Helper function:

internal static void FindChildren<T>(List<T> results, DependencyObject startNode) where T : DependencyObject
{
    int count = VisualTreeHelper.GetChildrenCount(startNode);
    for (int i = 0; i < count; i++)
    {
        DependencyObject current = VisualTreeHelper.GetChild(startNode, i);
        if ((current.GetType()).Equals(typeof(T)) || (current.GetType().GetTypeInfo().IsSubclassOf(typeof(T))))
        {
            T asType = (T)current;
            results.Add(asType);
        }
        FindChildren<T>(results, current);
    }
}

Accessing the button:

public MainPage()
{
    this.InitializeComponent();
    Loaded += (sender, e) =>
    {
        List<Button> results = new List<Button>();
        FindChildren(results, Hub);
        var mapButton = results.Find(item => item.Name.Equals("mapButton"));
        mapButton.Click += mapButton_Click;
    };
}

private void mapButton_Click(object sender, RoutedEventArgs arg)
{
    // Do something...
}

Although if you really wanted to map a command to Click , you should consider doing it in the XAML through binding .