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Created attachment 5962 [details]
I get an ArgumentNullException with this code:
var attributedString = new NSAttributedString("Hello, World!", foregroundColor: null);
That is unexpected because the default value for the foregroundColor (along with every other attribute argument) is null.
The reason I want this is that I am writing a method that does something like this:
private static void AppendStringToAttributedString(NSMutableAttributedString attributedString, string appendString, UIColor foregroundColor = null)
using (var attributedAppendString = new NSAttributedString(appendString, foregroundColor: foregroundColor))
I want to be able to call it like this:
using (var attributedString = new NSMutableAttributedString())
AppendStringToAttributedString("World!", foregroundColor: UIColor.Red);
The exception prevents me from doing this. :|
This should be fixed in both NSAttributedString and NSMutableAttributedString, and ideally anywhere else where this pattern exists.
After deploying attached sample on simulator we are getting same issue.
Exception Detail: https://gist.github.com/saurabh360/04e71a37998744db0750
IDE Log : https://gist.github.com/saurabh360/0d270b0c89a9fea74cef
The ObjC API uses an NSDictionary  and XI added a strongly-typed `UIStringAttributes` overload.
Internally this returns a NSDictionary (for consumption by the ObjC API) but can return `null` if no member is set (that code is used elsewhere).
Sadly  does not specify allowing null so there's no [NullAllowed] in the bindings. OTOH it likely does allow null (most similar API does, but I'll confirm/test that) and adding a [NullAllowed] would fix this (otherwise I'll fix the 2nd code part, which returns a null instead of an empty dictionary).
A nil NSDictionary is accepted by the ObjC API.
Fixed in master 83a12543a40bb24299ed45ed60fe01732b322e98
QA: unit tests added in the same revision
I have checked this issue on following builds:
Xamarin Studio : 4.2.4 (build 32)
Xamarin.iOS : 220.127.116.11 (Trial Edition)
Release ID: 402040032
Git revision: a160c35dac9ab9fd32eeadaa171216316d5a5133
Build date: 2014-03-12 13:55:08-04
Xamarin addins: a779416ceabd54981ce812771a4061c942e8b872
I observe that now I am not getting an ArgumentNullException with the following code:
"var attributedString = new NSAttributedString("Hello, World!", foregroundColor:null);"
I have check this issue with attached project for "NSAttributedString" and "NSMutableAttributedString" and these are working fine.
This issue is working fine.Hence, I am closing this issue.
Please let me know if I have to check anything else.