XAML designer can't recognize other control properties (VS 2015)

Question

I've recently installed Visual Studio 2015 Community, and I have a big WPF project initially developed in Visual Studio 2010, then, continued in Visual Studio 2012 Ultimate. The problem is that in this project I have some controls with properties set like that:

    private string _Header = "";
    public string TextHeader
    {
        get { return _Header; }
        set
        {
            _Header = value;
            if (_Header == string.Empty)
            {
                lTitle.Visibility = Visibility.Hidden;
                iSeparator.Visibility = Visibility.Hidden;
            }
            else
            {
                lTitle.Content = _Header;
                lTitle.Visibility = Visibility.Visible;
                iSeparator.Visibility = Visibility.Visible;
            }
        }
    }

I had no problems in the XAML designer in VS 2012, now, in this version of Visual Studio (2015), I'm unable to use the designer, it throws an error " Can't recognize or can't access the member "TextHeader" ".

I don't have debug problems, the application runs with no problems, no exceptions and no problems in the controls that use these properties, and I think that is a problem with the XAML designer.

My project Framework version is 3.5 and target platform is x64.

Answer 1

Properties that you want to set via XAML should be registered first. So, in your case code should be:

public static readonly DependencyProperty TextHeaderProperty = DependencyProperty.Register("TextHeader", typeof(string), typeof(StyledPanel))

public string TextHeader
{
    get { return (string)GetValue(TextHeaderProperty); }
    set { SetValue(TextHeaderProperty, value); }
}

This article explains DependencyProperties very well.

Note that after this changes you should rebuild your application.

Edit

Callback:

    public static readonly DependencyProperty TextHeaderProperty = DependencyProperty.Register(
        "TextHeader", 
        typeof(string), 
        typeof(StyledPanel), 
        new PropertyMetadata(TextHeaderPropertyChanged));

    private static void TextHeaderPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        var instance = sender as StyledPanel;
        if (String.IsNullOrEmpty(instance.TextHeader))
        {
            instance.lTitle.Visibility = Visibility.Hidden;
            instance.iSeparator.Visibility = Visibility.Hidden;
        }
        else
        {
            instance.lTitle.Content = _Header;
            instance.lTitle.Visibility = Visibility.Visible;
            instance.iSeparator.Visibility = Visibility.Visible;
        }
    }

Hope, it helps