Review analyzers for default Xamarin.Forms controls

[mrlacey]

Depends on #163

[mrlacey]

For Image, add a check on file name format

https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/images?tabs=windows

To use the same image filename across all platforms the name must be valid on all platforms. Android drawables have naming restrictions – only lowercase letters, numbers, underscore, and period are allowed – and for cross-platform compatibility this must be followed on all the other platforms too. The example filename waterfront.png follows the rules, but examples of invalid filenames include "water front.png", "WaterFront.png", "water-front.png", and "wåterfront.png".

[mrlacey]

For Line check on if the Fill property is set

https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/shapes/line

Setting the Fill property of a Line has no effect, because a line has no interior.

[mrlacey]

Add analyzer for Map.Pin
must set a Label

https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/map/pins#display-a-pin

[mrlacey]

If a WebView is inside a StackLayout, ensure WidthRequest and HeightRequest are set

https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/webview?tabs=windows

It may be necessary to set the WidthRequest and HeightRequest properties of the WebView to see the HTML content, depending upon the layout the WebView is a child of. For example, this is required in a StackLayout.

[mrlacey]

For Slider check that Minimum is less than Maximum

[mrlacey]

For Slider, check if ThumbColor and ThumbImageSource are set.

https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/slider

The ThumbColor and ThumbImageSource properties are mutually exclusive. If both properties are set, the ThumbImageSource property will take precedence.

[mrlacey]

For Stepper check that Minimum is less than Maximum

[mrlacey]

For DatePicker try and ensure MinimumDate is less than or equal to MaximumDate

https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/datepicker

Need to consider date formatting if do this.

Can't do this (yet) as don't know project-level settings for locale :(

[mrlacey]

For ProgressBar

https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/progressbar

Do not use unconstrained horizontal layout options such as Center, Start, or End with ProgressBar. On UWP, the ProgressBar collapses to a bar of zero width. Keep the default HorizontalOptions value of Fill and don't use a width of Auto when putting a ProgressBar in a Grid layout.

[mrlacey]

Don't put a ViewCell in a Carousel

https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/carouselview/populate-data

When using CarouselView, never set the root element of your DataTemplate objects to a ViewCell. This will result in an exception being thrown because CarouselView has no concept of cells.

[mrlacey]

This functionality has been released as part of v 0.12.0 and is available now.