Using UIModel Class For Binding In WPF

When creating WPF applications, you use binding. It’s a very nice workflow except for one point, where I want to bing the ContentProperty of a Label or a TextBlock. If I set this up in the xaml code with {Binding}, then I don’t have the “feeling” of the designer since there is no text until it compiles.

When creating WPF applications, you use binding. It’s a very nice workflow except for one point, where I want to bing the ContentProperty of a Label or a TextBlock. If I set this up in the xaml code with {Binding}, then I don’t have the “feeling” of the designer since there is no text until it compiles.

You can use “SetBinding” method for this programmatically in code, and having this in mind I decided that I need an UIModel class that encapsulates the logic of it.

The usage of SetBinding is,

public BindingExpression SetBinding(
    DependencyProperty dp,
    string path
)

First I created a class that would store the information I need. I also store the propertyinfo

public class UIControledElement
  {
      //ui element from the window
      public FrameworkElement Element { get; set; }
      //dependency property to affect. Set in the attribute in the class
      public DependencyProperty LanguageProperty { get; set; }
      //property info
      public PropertyInfo UiModelProperty { get; set; }
  }

The Base model is a bit more complex

public class UIModel<TWindow> where TWindow : Window
    {
        //I need the context which is the MainWindow to get the tagged properties
        private static TWindow context;
        //Because the register method below is static, this element is also static
        private static List<UIControledElement> UIControledElements = new List<UIControledElement>();

        public UIModel(TWindow context)
        {
            UIModel<TWindow>.context = context;
            UIModel<TWindow>.context.ContentRendered += Context_ContentRendered;
        }
        //Making sure that all elements are loaded and rendered, afterwards we make the changes required
        private void Context_ContentRendered(object sender, EventArgs e)
        {
            this.UpdateDisplay();
        }
        //this method is called in the child class to register a property. Because at this point the object doesn;t exist
        //we need to call it statically. In here we also store the DependencyProperty that we will alter
        protected static UIControledElement Register
(string PropertyInfo, DependencyProperty Property, Type Owner) {
            var propertyInfo =
Owner.GetProperty(PropertyInfo, BindingFlags.Public | BindingFlags.Instance);

if (propertyInfo != null) {
   var uicontroled = new UIControledElement { UiModelProperty = propertyInfo, LanguageProperty = Property };
   UIModel<TWindow>.UIControledElements.Add(uicontroled);
   return uicontroled;
            }
            return null;
        }
        //this method returns the UIElement
        protected FrameworkElement GetValue(UIControledElement Element)
{ return Element.Element; }
        //this methods sets the UIElement
        protected void SetValue(UIControledElement Element, FrameworkElement Value)
{Element.Element = Value;}

        //in this method we get the value from the attribute and call the function SetProperty
        private void UpdateDisplay()
        {
            foreach (var item in UIModel<TWindow>.UIControledElements)
            {
DisplayAttribute Attribute =
item.UiModelProperty.GetCustomAttribute(typeof(DisplayAttribute))
as DisplayAttribute;

                if (Attribute == null) return;

                SetProperty(item.Element, item.LanguageProperty, Attribute.Name);
            }
        }

        //this method alters the DependencyProperty of the UIElement with the value from an attribute
        private void SetProperty(FrameworkElement Element, DependencyProperty Property, object value) {
            Type depencendyObjectType = typeof(DependencyObject);

            MethodInfo SetValueMethodInfo =
                depencendyObjectType.GetMethod("SetValue",
new Type[] { typeof(DependencyProperty), typeof(object) });

            SetValueMethodInfo.Invoke(Element, new object[] { Property, value });
        }

    }

So far we made the infrastructure. Now we make our class

public class UINumberModel: UIModel < MainWindow >
  {
    private static UIControledElement exampleText = Register("ExampleText", Label.ContentProperty, typeof(UINumberModel));
    [Display(Name = "Bla Bla")]
    public FrameworkElement ExampleText {
        get {
            return GetValue(exampleText);
        }
        set {
            SetValue(exampleText, value);
        }
    }
    public UINumberModel(MainWindow context): base(context) {}
}

Usage

public MainWindow()
        {
            InitializeComponent();
            UINumberModel m = new UINumberModel(this) { ExampleText = LabelIO };
        }

When not compiled, Label will have a content, when compiled it will take the attribute and replace the content. The attribute can also be linked to a Language.Res file.