Trying updating FSharpExample to net5.0 (#1479)

* Trying updating to net5.0

* Fixes error. Thanks to @En3Tho

* Changed to the correct event.

* Cleaning on shutdown.

FSharpExample/FSharpExample.fsproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net5.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
@@ -14,7 +14,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Update="FSharp.Core" Version="4.7.2" />
+    <PackageReference Update="FSharp.Core" Version="6.0.0" />
   </ItemGroup>
 
 </Project>

FSharpExample/Program.fs

@@ -235,11 +235,11 @@ let ShowHex (top: Toplevel) =
 
 type MenuItemDetails () =
     inherit MenuItem ()
-    new (title: ustring, help: string, action: Action) as this =
+    new (title: ustring, help: ustring, action: Action) as this =
         MenuItemDetails ()
         then
             this.Title <- title
-            this.Help <- ustr help
+            this.Help <- help
             this.Action <- action
 
     static member Instance (mi: MenuItem) =
@@ -362,10 +362,10 @@ let Main () =
             Width = Dim.Fill () - Dim.op_Implicit margin,
             Height = Dim.Fill () - Dim.op_Implicit margin)
     let menuItems =
-        [|MenuItemDetails (ustr "F_ind", "", Unchecked.defaultof<_>);
-            MenuItemDetails (ustr "_Replace", "", Unchecked.defaultof<_>);
-            MenuItemDetails (ustr "_Item1", "", Unchecked.defaultof<_>);
-            MenuItemDetails (ustr "_Also From Sub Menu", "", Unchecked.defaultof<_>)|]
+        [|MenuItemDetails (ustr "F_ind",ustr "", Unchecked.defaultof<_>);
+            MenuItemDetails (ustr "_Replace", ustr "", Unchecked.defaultof<_>);
+            MenuItemDetails (ustr "_Item1", ustr "", Unchecked.defaultof<_>);
+            MenuItemDetails (ustr "_Also From Sub Menu", ustr "", Unchecked.defaultof<_>)|]
     menuItems.[0].Action <- fun _ -> ShowMenuItem (menuItems.[0])
     menuItems.[1].Action <- fun _ -> ShowMenuItem (menuItems.[1])
     menuItems.[2].Action <- fun _ -> ShowMenuItem (menuItems.[2])
@@ -381,25 +381,29 @@ let Main () =
                        MenuItem (ustr "_Disabled", ustring.Empty, (fun () -> ()), (fun () -> false))
                        Unchecked.defaultof<_>
                        MenuItem (ustr "_Quit", ustring.Empty, (fun () -> if Quit() then top.Running <- false)) |])
-               MenuBarItem (ustr "_Edit", 
+               MenuBarItem (ustr "_Edit",
                     [| MenuItem (ustr "_Copy", ustring.Empty, fun () -> Copy())
                        MenuItem (ustr "C_ut", ustring.Empty, fun () -> Cut())
                        MenuItem (ustr "_Paste", ustring.Empty, fun () -> Paste())
                        MenuBarItem (ustr "_Find and Replace",
-                           [| menuItems.[0]
-                              menuItems.[1] |])
-                       menuItems.[3] |])
+                           [| menuItems.[0] :> MenuItem
+                              menuItems.[1] :> MenuItem |]) :> MenuItem
+                       menuItems.[3] :> MenuItem
+                    |])
                MenuBarItem (ustr "_List Demos", 
                     [| MenuItem (ustr "Select _Multiple Items", ustring.Empty, (fun () -> ListSelectionDemo true))
                        MenuItem (ustr "Select _Single Item", ustring.Empty, (fun () -> ListSelectionDemo false)) |])   
-               MenuBarItem(ustr "A_ssorted",
+               MenuBarItem (ustr "A_ssorted",
                     [| MenuItem (ustr "_Show text alignments", ustring.Empty, (fun () -> ShowTextAlignments())) 
                        MenuItem (ustr "_OnKeyDown/Press/Up", ustring.Empty, (fun () -> OnKeyDownPressUpDemo())) |])
-               MenuBarItem(ustr "_Test Menu and SubMenus",
+               MenuBarItem (ustr "_Test Menu and SubMenus",
                     [| MenuBarItem (ustr "SubMenu1Item_1",
                             [| MenuBarItem (ustr "SubMenu2Item_1",
                                     [| MenuBarItem (ustr "SubMenu3Item_1",
-                                            [| menuItems.[2] |]) |]) |]) |])
+                                            [| menuItems.[2] :> MenuItem |]) :> MenuItem
+                                    |]) :> MenuItem
+                            |]) :> MenuItem
+                    |])
                MenuBarItem (ustr "_About...", ustr "Demonstrates top-level menu item", (fun () -> MessageBox.ErrorQuery (50, 7, ustr "Error", ustr "This is a demo app for gui.cs", ustr "Ok") |> ignore)) |])
     menuKeysStyle <- new CheckBox (3, 25, ustr "UseKeysUpDownAsKeysLeftRight", true)
     menuKeysStyle.add_Toggled (Action<bool> (MenuKeysStyleToggled))
@@ -431,15 +435,17 @@ let Main () =
     win.Add bottom
     let bottom2 = new Label (ustr "This should go on the bottom of another top-level!")
     top.Add bottom2
-    Application.Loaded <- Action<Application.ResizedEventArgs> (
-        fun _ ->
+    top.add_LayoutComplete (Action<View.LayoutEventArgs>
+        (fun e ->
             bottom.X <- win.X
             bottom.Y <- Pos.Bottom win - Pos.Top win - Pos.At margin
             bottom2.X <- Pos.Left win
             bottom2.Y <- Pos.Bottom win)
+        )
     top.Add win
     top.Add (menu, statusBar)
     Application.Run ()
+    Application.Shutdown ();
 
 module Demo =
     [<EntryPoint>]