Log using Microsoft.Extensions.Logging.Abstractions; implement WpfProgram

README.md

@@ -296,3 +296,29 @@ let save text =
 #### Can I bind to events and use behaviors?
 
 Sure! Check out the [EventBindingsAndBehaviors sample](https://github.com/elmish/Elmish.WPF/tree/master/src/Samples). Note that you have to install the NuGet package `Microsoft.Xaml.Behaviors.Wpf`.
+
+#### How can I control logging?
+
+Elmish.WPF uses `Microsoft.Extensions.Logging`. To see Elmish.WPF output in your favorite logging framework, use `WpfProgram.withLogger` to pass an `ILoggerFactory`:
+
+```f#
+WpfProgram.mkSimple init update bindings
+|> WpfProgram.withLogger yourLoggerFactory
+|> WpfProgram.runWindow window
+```
+
+For example, in Serilog, you need to install Serilog.Extensions.Logging and instantiate `SerilogLoggerFactory`. The samples demonstrate this.
+
+Elmish.WPF logs to these categories:
+
+* `Elmish.WPF.Update`: Logs exceptions (Error level) and messages/models (Trace/Verbose level) during `update`.
+* `Elmish.WPF.Bindings`: Logs events related to bindings. Some logging is done at the Error level (e.g. developer errors such as duplicated binding names, using non-existent bindings in XAML, etc.), but otherwise it’s generally just Trace/Verbose for when you really want to see everything that’s happening (triggering `PropertyChanged`, WPF getting/setting bindings, etc.)
+* `Elmish.WPF.Performance`: Logs the performance of the functions you pass when creating bindings (`get`, `set`, `map`, `equals`, etc.) at the Trace/Verbose level. Use `WpfProgram.withPerformanceLogThreshold` to set the minimum duration to log.
+
+The specific method of controlling what Elmish.WPF logs depends on your logging framework. For Serilog you can use `.MinimumLevel.Override(...)` to specify the minimum log level per category, like this:
+
+```f#
+myLoggerConfiguration
+  .MinimumLevel.Override("Elmish.WPF.Bindings", LogEventLevel.Verbose)
+  ...
+```

RELEASE_NOTES.md

@@ -3,10 +3,17 @@
 * **Breaking:** Removed the obsolete binding functions in the `BindingFn` module
 * **Breaking:** Removed the obsolete function `Elmish.WPF.Cmd.showWindow`
 * **Breaking:** Removed all occurrences of the argument `wrapDispatch` from the methods used to create a binding. There is currently no migration path. Please create an issue if this is a negative impact for you.
+* **Breaking:** App initialization is now done using the `WpfProgram` module instead of the `Program` module
+* **Breaking:** Removed `ElmConfig`. For controlling logging, see below. For specifying a binding performance log threshold (corresponding to the old `ElmConfig.MeasureLimitMs` field), use `WpfProgram.withBindingPerformanceLogThreshold`
 * Added binding mapping functions
   * Added `mapModel`, `mapMsg`, and `mapMsgWithModel` in both the `Binding` and `Bindings` modules
   * These functions enable common model and message mapping logic to be extracted
   * See the `SubModelSeq` sample for an excellent use of `mapModel` and `mapMsgWithMsg`
+* Improved logging:
+  * Now uses `Microsoft.Extensions.Logging` for wide compatibility and easy integration into common log frameworks
+  * Use `WpfProgram.WithLogger` to pass an `ILoggerFactory` for your chosen log framework
+  * Can control specific log categories
+  * See the samples for a demonstration using Serilog
 
 #### 3.5.6
 

src/Elmish.WPF.Tests/ViewModelTests.fs

@@ -6,6 +6,7 @@ open System.Collections.ObjectModel
 open System.Collections.Specialized
 open System.ComponentModel
 open System.Windows.Input
+open Microsoft.Extensions.Logging.Abstractions
 open FSharp.Interop.Dynamic
 open Xunit
 open Hedgehog
@@ -26,7 +27,7 @@ module Extensions =
 
 
 type internal TestVm<'model, 'msg>(model, bindings) as this =
-  inherit ViewModel<'model, 'msg>(model, (fun x -> this.Dispatch x), bindings, ElmConfig.Default, "")
+  inherit ViewModel<'model, 'msg>(model, (fun x -> this.Dispatch x), bindings, 1, "", NullLogger.Instance, NullLogger.Instance)
 
   let pcTriggers = ConcurrentDictionary<string, int>()
   let ecTriggers = ConcurrentDictionary<string, int>()

src/Elmish.WPF/Elmish.WPF.fsproj

@@ -33,16 +33,16 @@
     <Compile Include="AssemblyInfo.fs" />
     <Compile Include="InternalUtils.fs" />
     <Compile Include="InternalTypes.fs" />
-    <Compile Include="Config.fs" />
     <Compile Include="Binding.fs" />
     <Compile Include="Utils.fs" />
     <Compile Include="ViewModel.fs" />
     <Compile Include="ViewModelModule.fs" />
-    <Compile Include="Program.fs" />
+    <Compile Include="WpfProgram.fs" />
   </ItemGroup>
 
   <ItemGroup>
     <PackageReference Include="Elmish" Version="[3.0.3, 4)" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="3.1.6" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net461'">