dotnet/runtime

Support TypeConverterAttribute on bound properties

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#36,545 opened on Mar 18, 2017

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 (10 comments) (17 reactions) (0 assignees)C# (5,445 forks)batch import
area-Extensions-Configurationfeature-requesthelp wanted

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Description

It's very difficult to add a custom TypeConverter for framework types to have them bind correctly within ConfigurationBinder. The documentation for TypeConverterAttribute specifies that the attribute can be attached to a property, and that property will then use the specified TypeConverter during serialization/deserialization. Unfortunately, ConfigurationBinder doesn't take the property's attributes into consideration during BindProperty, instead passing the binding off to BindInstance with just the type of the property.

Presently, the only way to use custom TypeConverters is to register them using TypeDescriptor.AddAttributes before any configuration binding occurs, which is inconvenient if your library requires custom TypeConverters for standard types.

Contributor guide

Research direction
Examine the ConfigurationBinder source code, specifically the BindProperty method, and understand how TypeConverterAttribute can be detected and used during property binding. Look into the existing TypeConverter registration via TypeDescriptor.AddAttributes for reference.
Tech stack
csharp
Domain
backend
Issue type
Feature
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.
1-2 days
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#Configuration binding
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60