Panels are one of the most important control types of WPF. They act
as containers for other controls and control the layout of your
windows/pages. Since a window can only contain ONE child control, a
panel is often used to divide up the space into areas, where each area
can contain a control or another panel (which is also a control, of
course).
Panels come in several different flavors, with
each of them having its own way of dealing with layout and child
controls. Picking the right panel is therefore essential to getting the
behavior and layout you want, and especially in the start of your WPF
career, this can be a difficult job. The next section will describe each
of the panels shortly and give you an idea of when to use it. After
that, move on to the next chapters, where each of the panels will be
described in detail.
Canvas
A simple panel, which mimics the WinForms way of doing things. It allows
you to assign specific coordinates to each of the child controls,
giving you total control of the layout. This is not very flexible
though, because you have to manually move the child controls around and
make sure that they align the way you want them to. Use it (only) when
you want complete control of the child control positions.
WrapPanel
The WrapPanel will position each of its child controls next to the
other, horizontally (default) or vertically, until there is no more
room, where it will wrap to the next line and then continue. Use it when
you want a vertical or horizontal list controls that automatically
wraps when there's no more room.
StackPanel
The StackPanel acts much like the WrapPanel, but instead of wrapping if
the child controls take up too much room, it simply expands itself, if
possible. Just like with the WrapPanel, the orientation can be either
horizontal or vertical, but instead of adjusting the width or height of
the child controls based on the largest item, each item is stretched to
take up the full width or height. Use the StackPanel when you want a
list of controls that takes up all the available room, without wrapping.
DockPanel
The DockPanel allows you to dock the child controls to the top, bottom,
left or right. By default, the last control, if not given a specific
dock position, will fill the remaining space. You can achieve the same
with the Grid panel, but for the simpler situations, the DockPanel will
be easier to use. Use the DockPanel whenever you need to dock one or
several controls to one of the sides, like for dividing up the window
into specific areas.
Grid
The Grid is probably the most complex of the panel types. A Grid can
contain multiple rows and columns. You define a height for each of the
rows and a width for each of the columns, in either an absolute amount
of pixels, in a percentage of the available space or as auto, where the
row or column will automatically adjust its size depending on the
content. Use the Grid when the other panels doesn't do the job, e.g.
when you need multiple columns and often in combination with the other
panels.
UniformGrid
The UniformGrid is just like the Grid, with the possibility of multiple
rows and columns, but with one important difference: All rows and
columns will have the same size! Use this when you need the Grid
behavior without the need to specify different sizes for the rows and
columns.
