Bug 27143 - Extensions methods are not recognized without the 'this' modifier only in a Unified API app
Summary: Extensions methods are not recognized without the 'this' modifier only in a U...
Alias: None
Product: iOS
Classification: Xamarin
Component: General ()
Version: XI 8.6.0
Hardware: PC Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2015-02-17 09:18 UTC by John Miller [MSFT]
Modified: 2015-02-17 09:55 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

Test Case (17.50 KB, application/zip)
2015-02-17 09:18 UTC, John Miller [MSFT]

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Description John Miller [MSFT] 2015-02-17 09:18:58 UTC
Created attachment 9878 [details]
Test Case


   When using the Unified API, extensions methods are not recognized unless qualified with the "this" keyword. 

**Steps to Reproduce:**

   1. Try to build the attached TextTest project (Unified API app)

**Actual Results:**

   The extension method EndEditing for UITextField is not recognized. See screenshot:http://screencast.com/t/zBGApahG

**Expected Results:**

   The method should be recognized and not require the "this" keyword. 

**Build Date & Platform:**

   Mono 3.12

**Additional Information:**

   There is a Classic API project in the solution to show this is not an issue when using the Classic API. 
   Workaround: use the "this" keyword
Comment 1 Rolf Bjarne Kvinge [MSFT] 2015-02-17 09:55:08 UTC
This is just how C# works, extension methods can only be invoked using an instance expression (the implicit 'this' inside instance methods is not enough) [1]

This is a deliberate API difference between Classic and Unified.

[1] https://msdn.microsoft.com/en-us/library/bb308966.aspx#csharp3.0overview_topic6