Grid and StackPanel

Grid and StackPanel are the two panels you will reach for most often in everyday WPF development. Grid divides available space into a matrix of rows and columns defined via RowDefinitions and ColumnDefinitions, and each child is placed into a specific cell using the attached properties Grid.Row and Grid.Column, with Grid.RowSpan and Grid.ColumnSpan allowing a child to occupy multiple cells. StackPanel, by contrast, has no concept of cells at all — it simply lays children out one after another along a single axis, controlled by its Orientation property, which defaults to Vertical. Because Grid gives you precise two-dimensional control while StackPanel gives you simple one-dimensional flow, most real applications combine both: a Grid for the overall page skeleton, and StackPanel for smaller linear groupings like a button bar within one of the Grid's cells.

Grid supports three sizing modes for rows and columns: Auto, which sizes to the content's natural size; a fixed pixel value, like Width="100"; and star sizing (denoted with *), which distributes remaining space proportionally after Auto and fixed-size rows/columns have been allocated. For instance, a ColumnDefinitions list of Auto, *, 2* gives the first column exactly as much width as its content needs, then splits the remaining space so the third column gets twice as much as the second. Grid also supports a ShowGridLines debugging property and GridSplitter controls that let the end user drag to resize adjacent rows or columns interactively, which is common in tool-window-style applications like a code editor's file explorer next to the editing pane.

StackPanel measures each child with essentially infinite space along its stacking axis and gives each child its natural DesiredSize along that axis, while constraining the cross-axis to the StackPanel's own available width (for Vertical orientation) or height (for Horizontal orientation). This makes StackPanel extremely simple to reason about but also means it does not truncate or wrap overflow content — if the combined height of a vertical StackPanel's children exceeds the visible area, the extra content is simply clipped or pushed off-screen unless the StackPanel is itself hosted inside a ScrollViewer. A very common pattern is a horizontal StackPanel used as a button bar at the bottom of a dialog, where each Button's Margin provides spacing between siblings since StackPanel itself has no built-in item-spacing property.

The idiomatic WPF pattern is to use Grid for the outer skeleton of a view — separating a header, a main content area, and a footer into rows, or a navigation rail and content pane into columns — and then drop a StackPanel into individual Grid cells wherever you need a simple linear grouping, such as a vertical stack of form fields or a horizontal row of action buttons. Because Grid.Row and Grid.Column are attached properties, a StackPanel placed inside a Grid simply sets Grid.Row="1" on itself; it does not need to know anything about the Grid's row/column definitions beyond that. This separation of concerns — Grid for macro-structure, StackPanel for micro-structure — keeps XAML readable and avoids using Grid's more verbose row/column syntax for trivial single-axis groupings.