How can I Access user control by identifier (Name,Uid...)?

Question

I have a number (16 so far) of instances of user controls that I have built. Every one ot them have similar Properties. To each I gave a name: x:Name = "probeX" (where X is an int number). Each of these controls represent an electric probe.

I want to write a method that can access the user control by passed int value, to one of his properties.

For example: If the methods signature is: void SetMeasuredValueToProbe(int probe_number, int value ) then passing SetMeasuredValueToProbe(3, 22);

will sets "probe3" specific property to value 22.

I know that I can just make long switch case inside a method. But in the future I would like to exponentialy increace the number of the probes. So I would like to know what is the correct way to name and access an array of user controls.

XAML:

    <StackPanel
        Grid.Column="0">
        <uc:ProbeTestControl x:Name="probe1" x:Uid="1" ProbeValue ="1"/>
        <uc:ProbeTestControl x:Name="probe2" ProbeValue ="2"/>
        <uc:ProbeTestControl x:Name="probe3" ProbeValue ="3"/>
        <uc:ProbeTestControl x:Name="probe4" ProbeValue ="4"/>
        <uc:ProbeTestControl x:Name="probe5" ProbeValue ="5"/>
        <uc:ProbeTestControl x:Name="probe6" ProbeValue ="6"/>
        <uc:ProbeTestControl x:Name="probe7" ProbeValue ="7"/>
        <uc:ProbeTestControl x:Name="probe8" ProbeValue ="8"/>
    </StackPanel>
    <StackPanel
        Grid.Column="1">
        <uc:ProbeTestControl x:Name="probe9" ProbeValue ="9"/>
        <uc:ProbeTestControl x:Name="probe10" ProbeValue ="10"/>
        <uc:ProbeTestControl x:Name="probe11" ProbeValue ="11"/>
        <uc:ProbeTestControl x:Name="probe12" ProbeValue ="12"/>
        <uc:ProbeTestControl x:Name="probe13" ProbeValue ="13"/>
        <uc:ProbeTestControl x:Name="probe14" ProbeValue ="14"/>
        <uc:ProbeTestControl x:Name="probe15" ProbeValue ="15"/>
        <uc:ProbeTestControl x:Name="probe16" ProbeValue ="16"/>
    </StackPanel>

method in a MainWindow Class:

    private void SetMeasuredValueToProbe(int probe_number, int value )
    {
        switch (probe_number)
        {
            case 1:
                probe1.MeasuredValueBox = value;
                break;
            case 2:
                probe2.MeasuredValueBox = value;
                break;
            default:
                break;                       
        }             
    }

I want to know the elegant way to do so, without making a spaghetti code.

score 0 · Accepted Answer · answered Oct 11 '19 at 15:46

One approach could be to give an x:Name to the root Grid:

<Grid x:Name="LayoutRoot">
    ...
</Grid>

Then in your code, you could find the probe user controls by name. Something like this:

var probe = LayoutRoot.GetChildByName<ProbeTestControl>($"probe{probe_number}");

Here is the extension method(s) that I use:

public static T GetChildByName<T>(this FrameworkElement element, string name)
    where T : FrameworkElement
{
    if (element == null) return null;
    return (T)element.FindName(name) ?? element.GetChildrenOfType<T>().FirstOrDefault(c => c.Name == name);
}

public static IEnumerable<T> GetChildrenOfType<T>(this DependencyObject element)
    where T : DependencyObject
{
    return element.GetChildrenRecursive().OfType<T>();
}

private static IEnumerable<DependencyObject> GetChildrenRecursive(this DependencyObject element)
{
    if (element == null)
    {
        throw new ArgumentNullException(nameof(element));
    }

    for (var i = 0; i < VisualTreeHelper.GetChildrenCount(element); i++)
    {
        var child = VisualTreeHelper.GetChild(element, i);

        yield return child;

        foreach (var item in child.GetChildrenRecursive())
        {
            yield return item;
        }
    }
}

As long as all the probes exist in the same XAML tree, everything should work.

I hope this helps.

How can I Access user control by identifier (Name,Uid...)?

1 Answers1