Allow project to use iOS 13

dotnet/ios/ios13/UsingCollectionViewCompositionalLayoutsAndDiffableDataSources/Conference-Diffable/Conference-Diffable.csproj

@@ -5,7 +5,7 @@
     <OutputType>Exe</OutputType>
     <Nullable>enable</Nullable>
     <ImplicitUsings>true</ImplicitUsings>
-    <SupportedOSPlatformVersion>14.0</SupportedOSPlatformVersion>
+    <SupportedOSPlatformVersion>13.0</SupportedOSPlatformVersion>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 </Project>

dotnet/ios/ios13/UsingCollectionViewCompositionalLayoutsAndDiffableDataSources/Conference-Diffable/Diffable/TableViewEditingViewController.cs

@@ -199,10 +199,8 @@ public partial class TableViewEditingViewController : UIViewController {
 				// Get a cell of the desired kind.
 				var cell = tableView.DequeueReusableCell (key) ?? new UITableViewCell (UITableViewCellStyle.Subtitle, key);
 
-				var content = cell.DefaultContentConfiguration;
-				content.Text = mountain.Name;
-				content.SecondaryText = formatter.StringFromNumber (NSNumber.FromInt32 (mountain.Height));
-				cell.ContentConfiguration = content;
+				var secondaryText = formatter.StringFromNumber (NSNumber.FromInt32 (mountain.Height));
+				cell.AddTextLabel (mountain.Name, secondaryText);
 
 				// Return the cell.
 				return cell;

dotnet/ios/ios13/UsingCollectionViewCompositionalLayoutsAndDiffableDataSources/Conference-Diffable/Diffable/WiFiSettingsViewController.cs

@@ -153,18 +153,15 @@ public class WiFiSettingsViewController : UIViewController {
 			if (obj is Item item) {
 				// Get a cell of the desired kind.
 				var cell = tableView.DequeueReusableCell (key, indexPath);
-				var content = cell.DefaultContentConfiguration;
 
 				// network cell
 				if (item.IsNetwork) {
-					content.Text = item.Title;
-					cell.ContentConfiguration = content;
+					cell.AddTextLabel (item.Title);
 					cell.Accessory = UITableViewCellAccessory.DetailDisclosureButton;
 					cell.AccessoryView = null;
 				} else if (item.IsConfig) {
 					// configuration cells
-					content.Text = item.Title;
-					cell.ContentConfiguration = content;
+					cell.AddTextLabel (item.Title);
 
 					if (item.Type == ItemType.WifiEnabled) {
 						var enableWifiSwitch = new UISwitch { On = wifiController.WifiEnabled };

dotnet/ios/ios13/UsingCollectionViewCompositionalLayoutsAndDiffableDataSources/Conference-Diffable/GlobalSuppressions.cs

@@ -0,0 +1,8 @@
+// This file is used by Code Analysis to maintain SuppressMessage
+// attributes that are applied to this project.
+// Project-level suppressions either have no target or are given
+// a specific target and scoped to a namespace, type, member, etc.
+
+using System.Diagnostics.CodeAnalysis;
+
+[assembly: SuppressMessage("Interoperability", "CA1416:Validate platform compatibility", Justification = "<Pending>", Scope = "member", Target = "~M:Conference_Diffable.UITableViewCellExtensions.AddTextLabel(UIKit.UITableViewCell,System.String,System.String)")]

dotnet/ios/ios13/UsingCollectionViewCompositionalLayoutsAndDiffableDataSources/Conference-Diffable/UITableViewCellExtensions.cs

@@ -0,0 +1,25 @@
+namespace Conference_Diffable;
+
+public static class UITableViewCellExtensions
+{
+	public static void AddTextLabel (this UITableViewCell cell, string text, string secondaryText = "")
+	{
+		// Beginning in iOS 14, UITableViewCell has to use cell.ContentConfiguration
+		// to add text
+		if (UIDevice.CurrentDevice.CheckSystemVersion (14, 0))
+		{
+			var content = cell.DefaultContentConfiguration;
+			content.Text = text;
+
+			if (!string.IsNullOrEmpty (secondaryText))
+				content.SecondaryText = secondaryText;
+
+			cell.ContentConfiguration = content;
+		} else {
+			cell.TextLabel.Text = text;
+
+			if (!string.IsNullOrEmpty (secondaryText))
+				cell.DetailTextLabel.Text = secondaryText;
+		}
+	}
+}