Guide to Customizing Existing Controls

[stevemonaco]

Questions regarding how to customize existing controls are asked more often than probably any other category of Avalonia question. A guide should be created to address this knowledge gap of a reliable process. Most topic pages will have several links to other pages that cover the concept.

Rough list of topics:

• Locating Relevant Properties using DevTools
  • Visual Tree
  • Active/Inactive Style Selectors
  • TemplatedParent
• Locating Originating ControlTheme
  • Simple/Fluent
  • Third-party
  • Emphasize General Importance of Reading ControlThemes
• Types of Possible Visual Modifications Without Copying ControlTheme
  • Style selectors
  • Overriding resources
  • Setter precedence (prerequisite, link to doc)
• Types of Impossible Visual Modifications Without Copying ControlTheme
  • Customize local set value
  • Changing XAML tree structure
• Local Inclusion of Copied ControlTheme (when modification is impossible)
• Create an alternate look for a control that already has a desired default look
• Modifying or Adding Behavior to Existing Controls
  • Attached behaviors/properties
  • Tunnel events
    • Example with TextBox key input filtering
  • Inherit -> custom control (StyleKeyOverride)
  • Limitations

Docs Location: How-To Guides

Looking for feedback/general interest as I will probably author this.