Binding in Control with "Class" Attribute

Binding in Control with class Attribute

UI5 doesn't support binding for class in XML view directly as it's not a valid property of ManagedObject. Nevertheless, there is a workaround by adding custom data:

1. Add CustomData with the property writeToDom to your control. Use your expression binding there:

   <ControlXYZ class="myControl">
     <customData>
       <core:CustomData xmlns:core="sap.ui.core"
         key="green"
         value="foo"
         writeToDom="{= expression}"
       />
     </customData>
   </ControlXYZ>

   Depending on the outcome of your expression binding, data-green will be added to the control's HTML element. The browser can then manipulate the color corresponding to the attribute selector.

2. Your CSS should thus include the selector accordingly:

   .myApp .sapControlXYZ.myControl[data-green] { /* ... */ }

Here is an example: https://embed.plnkr.co/LAv1qfsUjX0Anu7S/

Of course, you can also bind anything you want to the value property of the CustomData in order to react on more granular CSS selectors. To learn more about how to leverage custom data in DOM, check out the documentation topic Writing Data to the HTML DOM as DATA-* Attribute.

---

⚠️ Before using custom CSS..

• There might be controls which don't require custom CSS. Especially when it comes to styling sap.m.Text for example, there is:

  • Text with semantic colors: sap.m.ObjectStatus or .ObjectNumber.
  • Text with custom format: sap.m.FormattedText.

• SAP explicitly warns not to use custom CSS styles.

  As stated in the Compatibility Rules, the HTML and CSS generated by SAPUI5 is not part of the public API [...]. As such, SAP Fiori launchpad apps should not override styles.

  Generally, the importance of adding custom CSS styles should be always questioned and double-checked with stakeholders to improve UI consistency across Fiori apps as well as to reduce the maintenance costs and TCO that would otherwise rise significantly with custom CSS.

Data binding of CSS class attribute in XML view

Unfortunately, it is indeed not possible to bind the class attribute, as Qualiture already mentioned.
However, there is a workaround using custom data, which can be bound, written to the DOM and hence also used for styling purposes.
You can see an example here in the documentation: Writing Data to the HTML DOM as DATA-* Attribute

Hope that helps

How to bind UI color attribute with class property

Try to bind to the State property of the UserControl:

<Ellipse Fill="{Binding Path=State, 
    RelativeSource={RelativeSource AncestorType=UserControl}, 
    Converter={StaticResource BoolToColor}}" StrokeThickness="3" Stroke="Gray"/>

You should also return a Brush instead of a Color from your converter:

public class BoolToColor : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is bool)
        {
            if ((bool)value == true)
                return Brushes.Green; // to replace with onColor
            else
                return Brushes.Red;  // to replace with offColor
        }
        return Brushes.LightGray;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is Brush)
        {
            if ((Brush)value == Brushes.Green) // to compare with onColor
            {
                return true;
            }
        }
        return false;
    }
}

Bind different properties of a Class to two instances of the same UserControl

You could add a string dependency property to the UserControl class (TextBoxUC.xaml.vb):

Public Class TextBoxUC

    Public Property Text() As String
        Get
            Return CType(Me.GetValue(TextProperty), Boolean)
        End Get
        Set(ByVal value As String)
            Me.SetValue(TextProperty, value)
        End Set
    End Property

    Public Shared ReadOnly TextProperty As DependencyProperty = DependencyProperty.Register("Text", GetType(String), GetType(TextBoxUC), New PropertyMetadata(Nothing))
End Class

And bind the TextBox in the UserControl (TextBoxUC.xaml) to this one:

<TextBox x:Name="tbx" Text="{Binding Text, RelativeSource={RelativeSource AncestorType=UserControl}}" />

Then you could just bind this dependency property to a property of the Person DataContext as usual:

<Window x:Class="Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:ClassPropertiesToTextBox"
        mc:Ignorable="d"
        Title="Window1" Height="300" Width="300">
    <Window.DataContext>
        <local:Person FirstName="Mickey" LastName="Mouse" />
    </Window.DataContext>
    <StackPanel>
        <local:TextBoxUC Text="{Binding FirstName}" />
    </StackPanel>
</Window>

Edit: Or you could bind the dependency property programmatically:

p = New Person
p.FirstName = "Homer"
p.LastName = "Simpson"

tbxFirstNameUC = New TextBoxUC
'Set DataContext to my Person class instance'
tbxFirstNameUC.DataContext = p
tbxFirstNameUC.SetBinding(TextBoxUC.NameProperty, New Binding("FirstName"))

---

Related Topics