I'm very new to WPF. I'm used from windows forms, that I create a panel, place controls inside it and give them DockStyle.Fill to max out their size to the surrounding panel.
In WPF I want to have the same. I have a tab-control and I want its size to fill as much of the form as possible.
I have a ribbon control (RibbonControlsLibrary) and want the rest of the form to be filled with the tab control at max size.
(I do not want to dock controls like docking in Visual Studio, just old docking mechanisms)
The WPF equivalent of WinForms' DockStyle.Fill is:
This is the default for almost controls, so in general you don't have to do anything at all to have a WPF control fill its parent container: They do so automatically. This is true for all containers that don't squeeze their children to minimum size.
I will now explain several common mistakes that prevent
HorizontalAlignment="Stretch" VerticalAlignment="Stretch" from working as expected.
1. Explicit Height or Width
One common mistake is to explicitly specify a Width or Height for a control. So if you have this:
<Grid> <Button Content="Why am I not filling the window?" Width="200" Height="20" /> ... </Grid>
Just remove the Width and Height attributes:
<Grid> <Button Content="Ahhh... problem solved" /> ... </Grid>
2. Containing panel squeezes control to minimum size
Another common mistake is to have the containing panel squeezing your control as tight as it will go. For example a vertical StackPanel will always squeeze its contents vertically as small as they will go:
<StackPanel> <Button Content="Why am I squished flat?" /> </StackPanel>
Change to another Panel and you'll be good to go:
<DockPanel> <Button Content="I am no longer squished." /> </DockPanel>
Also, any Grid row or column whose height is "Auto" will similarly squeeze its content in that direction.
Some examples of containers that don't squeeze their children are:
Some examples of containers that do squeeze their children are:
3. Explicit Height or Width further out
It's amazing how many times I see Grid or DockPanel given an explicit height and width, like this:
<Grid Width="200" Height="100"> <Button Content="I am unnecessarily constrainted by my containing panel" /> </Grid>
In general you never want to give any Panel an explicit Height or Width. My first step when diagnosing layout problems is to remove every explicit Height or Width I can find.
4. Window is SizeToContent when it shouldn't be
When you use SizeToContent, your content will be squeezed to minimum size. In many applications this is very useful and is the correct choice. But if your content has no "natural" size then you'll probably want to omit SizeToContent.