xamarin/Xamarin.Forms

[Bug] [UWP] Template Disappears when Command Parameter Binding Set

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#8,918 opened on Dec 16, 2019

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4.4.0a/listviewe/5 :clock5:help wantedi/regressioninactivep/UWPt/bug :bug:up-for-grabs

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Description

Description

I have a Listview with simple DataTemplate selector which presents one of either two templates. Once the CommandParameter Binding is defined to the current object ({Binding} or {Binding .}), the entire view for that template goes blank on UWP. Therefore, I'm not allowed to call the command with the current object. This works as expected when deploying out to iOS.

Steps to Reproduce

Sample project here https://github.com/djrpascu/XFGithub

Expected Behavior

Listview template displays contents properly and I'm able to pass the object into my command via CommandParameter.

Actual Behavior

Listview template goes blank.

Basic Information

  • Version with issue: 4.4.0.991265

  • Last known good version: N/A

  • IDE: VS Enterprise 2019 16.4.1

  • Platform Target Frameworks:

    • iOS: 13
    • Android: N/A
    • UWP: 16299

  • Android Support Library Version: N/A

  • Nuget Packages: XF 4.4.0.991265 Prims.Unity.Forms 7.2.0.1422 NETStandard.Library 2.0.3

  • Affected Devices: Windows 10 Desktop

Screenshots

Reproduction Link

https://github.com/djrpascu/XFGithub

Contributor guide

Research direction
Investigate how CommandParameter binding affects DataTemplate rendering on UWP. Check if there is a known issue with binding context or template selection when CommandParameter is set. Use a debugger to step through the rendering process on UWP platform.
Tech stack
csharp
Domain
desktop
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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#Xamarin.Forms
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65