Version-gate some newer syntax

CHANGELIST.md

@@ -15,6 +15,7 @@
 - Enable nullability in MPF.Test
 - Handle some suggested changes
 - Var-ify many instances
+- Version-gate some newer syntax
 
 ### 2.7.0 (2023-10-11)
 

MPF.UI.Core/ElementConverter.cs

@@ -37,7 +37,11 @@ namespace MPF.UI.Core
 #endif
         {
             // If it's an IElement but ends up null
+#if NET48
             if (!(value is IElement element))
+#else
+            if (value is not IElement element)
+#endif
                 return null;
 
             switch (element)

MPF.UI.Core/UserControls/LogOutput.xaml.cs

@@ -168,13 +168,17 @@ namespace MPF.UI.Core.UserControls
         {
             Dispatcher.Invoke(() =>
             {
+#if NET48
                 if (lastLine == null) lastLine = new Run();
+#else
+                lastLine ??= new Run();
+#endif
                 lastLine.Text = logLine.Text;
                 lastLine.Foreground = logLine.GetForegroundColor();
             });
         }
 
-        #endregion
+#endregion
 
         #region Helpers
 

MPF.UI.Core/Windows/OptionsWindow.xaml.cs

@@ -57,7 +57,11 @@ namespace MPF.UI.Core.Windows
                 return;
 
             // Strips button prefix to obtain the setting name
+#if NET48
             string pathSettingName = button.Name.Substring(0, button.Name.IndexOf("Button"));
+#else
+            string pathSettingName = button.Name[..button.Name.IndexOf("Button")];
+#endif
 
             // TODO: hack for now, then we'll see
             bool shouldBrowseForPath = pathSettingName == "DefaultOutputPath";
@@ -124,7 +128,11 @@ namespace MPF.UI.Core.Windows
         /// <summary>
         /// Create an open folder dialog box
         /// </summary>
+#if NET48
         private static FolderBrowserDialog CreateFolderBrowserDialog() => new FolderBrowserDialog();
+#else
+        private static FolderBrowserDialog CreateFolderBrowserDialog() => new();
+#endif
 
         /// <summary>
         /// Create an open file dialog box