Color clustered features based on clustered point counts

Question

I'm developing an app using Xamarin.iOS and Mapbox iOS SDK (Naxam.Mapbox.iOS NuGet package here. And i'm following this example in MapBox iOS SDK website: https://docs.mapbox.com/ios/maps/examples/clustering/.

And i'm having problems converting this part of code to C#:

// Color clustered features based on clustered point counts.
let stops = [
    20: UIColor.lightGray,
    50: UIColor.orange,
    100: UIColor.red,
    200: UIColor.purple
]

And:

circlesLayer.circleColor = NSExpression(format: "mgl_step:from:stops:(point_count, %@, %@)", UIColor.lightGray, stops)

I'm able to set an unique color to the cluster if i do it like this:

circlesLayer.CircleColor = NSExpression.FromConstant(FromObject(UIColor.Green));

But i'm not managing to do it if i follow the example, in it, the Expression format takes 3 Parameters: string, UiColor, Array

But in C# NSExpression.FromConstant, takes at max 2 params: string and a NSObject[], so i created this: (to match the array "stops" in the examle)

NSDictionary[] stops = new NSDictionary[]
{
    new NSDictionary(new NSNumber(0), FromObject(UIColor.Green)),
    new NSDictionary(new NSNumber(20), FromObject(UIColor.Blue)),
    new NSDictionary(new NSNumber(100), FromObject(UIColor.Red))
};

But it no success, what should i be doing instead?

Answer 1

It should be an nsfloat rather than a integer, so define the first param like this:

new NSNumber(0f)

Answer 2

You can use NSExpression.FromFormat(string format, NSObject [] parameters) for this purpose.

Something like this:

circlesLayer.CircleColor = NSExpression.FromFormat ("mgl_step:from:stops:(point_count, %@, %@)", stops)

Where stops is what you had above with the dictionary.

Answer 3

Try this:

NSDictionary[] stops = new NSDictionary[]
{
    new NSDictionary(new NSNumber(0f), FromObject(UIColor.Green)),
    new NSDictionary(new NSNumber(20f), FromObject(UIColor.Blue)),
    new NSDictionary(new NSNumber(100f), FromObject(UIColor.Red))
};

Using nsfloat might be the way to go