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.NET MAUI - Custom layouts

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A .NET Multi-platform App UI (.NET MAUI) layout is a list of views with rules and properties that define how to arrange those views within a container. Examples of layouts include Grid, AbsoluteLayout, and VerticalStackLayout.

The process for creating a custom layout in .NET MAUI involves providing an ILayoutManager implementation, and overriding the following methods:

  • Size Measure(double widthConstraint, double heightConstraint)
  • Size ArrangeChildren(Rectangle bounds)

The Measure implementation should call measure on each IView in the layout, and should return the total size of the layout given the constraints. The ArrangeChildren implementation should determine where each IView should be placed within the given bounds, and should call Arrange on each IView with its appropriate bounds. The return value should be the actual size of the layout.

This sample demonstrates the following custom layouts:

  • CascadeLayout, which cascades items from top left to bottom right, similar to using the cascade windows arrangement in an MDI application.
  • ColumnLayout, which is similar to the Xamarin.Forms *AndExpand properties. It's a subclass of VerticalStackLayout, which adds a Fill attached property that can be applied to one or more children of the layout. It uses a custom layout manager that converts the VerticalStackLayout into a single-column Grid at runtime. Each VerticalStackLayout child gets its own row in the Grid. The rows are set to a height of Auto, but children marked as Fill receive a row height of * instead.
  • ContentColumnLayout, which is a custom layout that displays a header, content, and footer. It subclasses Layout and implements some extra properties and methods from the IGridLayout interface. This enables it to be passed into the GridLayoutManager to handle the layout at runtime.
  • HorizontalWrapLayout, which works like a horizontal stack layout, except that instead of extending out as far as it needs to the right, it will wrap to a new row when it encounters the right edge of its container.
  • ZStackLayout, which is a variation of a StackLayout that arranges its children on top of each other. All its children are laid out at the origin. The arrangement area's width is determined by the widest child and the height is determined by the tallest child.

In some situations you may find that you want to change the behavior of an existing layout type without having to create a custom layout. For those scenarios you can create an ILayoutManagerFactory and use it to replace the default layout manager type with your own. The CustomizedGridLayoutManager type in the sample demonstrates doing this.

Note

These layouts are not intended as production-ready layouts.

For more information about custom layouts, see Custom layouts.