WebView in Xamarin.Forms using Visual Studio 2019 | Getting Started
Xamarin.Forms is an open-source UI framework. Xamarin.Forms allows developers to build Xamarin.Android, Xamarin.iOS, and Windows applications from a single shared codebase.
Xamarin.Forms provides a consistent API for creating UI elements across platforms. This API can be implemented in either XAML or C# and supports databinding for patterns such as Model-View-ViewModel (MVVM).
At runtime, Xamarin.Forms utilizes platform renderers to convert the cross-platform UI elements into native controls on Xamarin.Android, Xamarin.iOS and UWP. This allows developers to get the native look, feel and performance while realizing the benefits of code sharing across platforms.
Xamarin.Forms applications typically consist of a shared .NET Standard library and individual platform projects. The shared library contains the XAML or C# views and any business logic such as services, models or other code. The platform projects contain any platform-specific logic or packages the application requires.
To solve this, you need to tell the WebView where to find files on the filesystem. Do that by setting the BaseUrl property on the HtmlWebViewSource used by the WebView.
Because the filesystem on each of the operating systems is different, you need to determine that URL on each platform. Xamarin.Forms exposes the DependencyService for resolving dependencies at runtime on each platform.