unoplatform/uno

Invalid binding breaks the dependency property inheritance

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#1,516 opened on Sep 10, 2019

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difficulty/starter 🚀good first issuehas-repro-branchkind/bugplatform/android 🤖platform/ios 🍎platform/wasm 🌐project/binding 🪢

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Description

Current behavior

If you write something like:

<ScrollViewer x:Name="PART_ScrollViewer"
    HorizontalScrollBarVisibility="{TemplateBinding ARandomMissingProperty}" />

The horizontal HorizontalScrollBarVisibility will be set toDependencyProperty.UnsetValue.

Expected behavior

HorizontalScrollBarVisibility should still be set to the inherited value.

Environment

Affected platform(s):

  • iOS
  • Android
  • WebAssembly
  • Windows
  • Build tasks

Contributor guide

Research direction
Trace the binding resolution in the TemplateBinding code path and fix the fallback when the property is missing to use inherited value instead of UnsetValue.
Tech stack
csharp
Domain
mobileweb dev
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C#XAML
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50