Migrating to 2025 December

Introduction

This page discusses breaking changes and other considerations when migrating from 2025 November to 2025 December .

Changed GraphicalUiElement Children Type

In previous versions the GraphicalUiElement (base class for all Visuals) included the following property:

// old:
public ObservableCollection<IRenderableIpso>? Children { get; }

The new property has changed to:

//new:
public ObservableCollection<GraphicalUiElement> Children { get; }

This change brings the following benefits:

• Children are now already casted to GraphicalUiElement, simplifying for loops and access by element.

• Children is now always non-null, simplifying code to no longer need to check for nulls before accessing Children

For example, the following blocks shows how old and new.

❌ Old:

var visual = myControl.Visual;
if(visual.Children != null)
{
    foreach(var item in visual.Children)
    {
        if(item is GraphicalUiElement asGraphicalUiElement)
        {
            DoSomethingTo(asGraphicalUiElement);
        }
    }
}

✅New:

var visual = myControl.Visual;

foreach(var item in visual.Children)
{
    DoSomethingTo(asGraphicalUiElement);
}

Any code that operates on the Children by taking an ObservableCollection<IPositionedSizedObject> needs to update to take an ObservableCollection<GraphicalUiElement>.

❌Old:

DoSomethingTo(myControl.Visual.Children);

void DoSomethingTo(ObservableCollection<IPositionedSizedObject> children)
{
    // ...
}

✅New:

DoSomethingTo(myControl.Visual.Children);

void DoSomethingTo(ObservableCollection<GraphicalUiElement> children)
{
    // ...
}

Alternatively if it is difficult to change calls which work on Children, you can still access the Children by casting the visual to an IPositionedSizedObject as shown in the following block:

var asIpso = (IPositionedSizedObject)myControl.Visual;

// If the GraphicalUiElement is cased to an IPositionedSizedObject, then
// the Children property is still of type ObservableCollection<GraphicalUiElement>
DoSomething(asIpso.Children);

void DoSomethingTo(ObservableCollection<IPositionedSizedObject> children)
{
    // ...
}