#1,165 – Layout in Action, part II

Layout in WPF dictates how layout panels (containers) arrange their child elements.  Below is a simple example of a StackPanel containing a custom Label that we’ve instrumented so that we can see when its Measure and Arrange methods are called.  (MyPanel derives from Label).

Suppose we use the label as follows:

    <StackPanel Margin="5" Background="Honeydew">
        <loc:MyLabel Content="Billy" Background="Thistle"
                     HorizontalAlignment="Center" />

The label looks like this at run-time:


At run-time, the measure/arrange process is:

  • StackPanel calls Measure on MyLabel
  • Base Label class calculates how much space it needs (31.4 x 26) and MyLabel returns this value from MeasureOverride
  • StackPanel decides to give the label the space that it needs/wants
  • StackPanel calls Arrange on MyLabel, passing in size of 31.4 x 26
  • MyLabel.ArrangeOverride receives this value, passing on to base Label class
  • Base Label class uses this size to know how to render label

Here’s some run-time output showing these values:


About Sean
Software developer in the Twin Cities area, passionate about .NET technologies. Equally passionate about my own personal projects related to family history and preservation of family stories and photos.

One Response to #1,165 – Layout in Action, part II

  1. Pingback: Dew Drop – September 24, 2014 (#1862) | Morning Dew

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