Add null checks to first extension method argument (#943)

Co-authored-by: Gerald Versluis <[email protected]>

Author: maxkoshevoi

src/CommunityToolkit/Xamarin.CommunityToolkit/Extensions/PageExtension.shared.cs

@@ -12,6 +12,8 @@ public static class PageExtension
 	{
 		public static Task DisplayToastAsync(this Page page, string message, int durationMilliseconds = 3000)
 		{
+			_ = page ?? throw new ArgumentNullException(nameof(page));
+
 			var messageOptions = new MessageOptions { Message = message };
 			var args = new SnackBarOptions
 			{
@@ -30,6 +32,8 @@ public static Task DisplayToastAsync(this Page page, string message, int duratio
 
 		public static Task DisplayToastAsync(this Page page, ToastOptions toastOptions)
 		{
+			_ = page ?? throw new ArgumentNullException(nameof(page));
+
 			var snackBar = new SnackBar();
 			var arguments = toastOptions ?? new ToastOptions();
 			var options = new SnackBarOptions
@@ -45,6 +49,8 @@ public static Task DisplayToastAsync(this Page page, ToastOptions toastOptions)
 
 		public static Task<bool> DisplaySnackBarAsync(this Page page, string message, string actionButtonText, Func<Task> action, int durationMilliseconds = 3000)
 		{
+			_ = page ?? throw new ArgumentNullException(nameof(page));
+
 			var messageOptions = new MessageOptions { Message = message };
 			var actionOptions = new List<SnackBarActionOptions>
 			{
@@ -71,6 +77,8 @@ public static Task<bool> DisplaySnackBarAsync(this Page page, string message, st
 
 		public static Task<bool> DisplaySnackBarAsync(this Page page, SnackBarOptions snackBarOptions)
 		{
+			_ = page ?? throw new ArgumentNullException(nameof(page));
+
 			var snackBar = new SnackBar();
 			var arguments = snackBarOptions ?? new SnackBarOptions();
 			snackBar.Show(page, arguments);

src/CommunityToolkit/Xamarin.CommunityToolkit/Extensions/VisualElementExtension.shared.cs

@@ -8,6 +8,8 @@ public static class VisualElementExtension
 	{
 		public static Task<bool> ColorTo(this VisualElement element, Color color, uint length = 250u, Easing easing = null)
 		{
+			_ = element ?? throw new ArgumentNullException(nameof(element));
+
 			var animationCompletionSource = new TaskCompletionSource<bool>();
 			new Animation
 			{
@@ -21,6 +23,8 @@ public static Task<bool> ColorTo(this VisualElement element, Color color, uint l
 
 		public static void AbortAnimations(this VisualElement element, params string[] otherAnimationNames)
 		{
+			_ = element ?? throw new ArgumentNullException(nameof(element));
+
 			ViewExtensions.CancelAnimations(element);
 			element.AbortAnimation(nameof(ColorTo));
 
@@ -33,6 +37,8 @@ public static void AbortAnimations(this VisualElement element, params string[] o
 
 		internal static bool TryFindParentElementWithParentOfType<T>(this VisualElement element, out VisualElement result, out T parent) where T : VisualElement
 		{
+			_ = element ?? throw new ArgumentNullException(nameof(element));
+
 			result = null;
 			parent = null;
 			while (element.Parent != null)

src/CommunityToolkit/Xamarin.CommunityToolkit/Helpers/WeakEventManager.shared.cs

@@ -121,6 +121,11 @@ public static class WeakEventManagerExtensions
 		/// <param name="sender">Sender</param>
 		/// <param name="eventArgs">Event arguments</param>
 		/// <param name="eventName">Event name</param>
-		public static void RaiseEvent(this Forms.WeakEventManager weakEventManager, object sender, object eventArgs, string eventName) => weakEventManager.HandleEvent(sender, eventArgs, eventName);
+		public static void RaiseEvent(this Forms.WeakEventManager weakEventManager, object sender, object eventArgs, string eventName)
+		{
+			_ = weakEventManager ?? throw new ArgumentNullException(nameof(weakEventManager));
+
+			weakEventManager.HandleEvent(sender, eventArgs, eventName);
+		}
 	}
 }

src/CommunityToolkit/Xamarin.CommunityToolkit/Helpers/WeakEventManagerService.shared.cs

@@ -171,6 +171,8 @@ static DynamicMethod TryGetDynamicMethod(in MethodInfo rtDynamicMethod)
 
 		static bool IsLightweightMethod(this MethodBase method)
 		{
+			_ = method ?? throw new ArgumentNullException(nameof(method));
+
 			var typeInfoRTDynamicMethod = typeof(DynamicMethod).GetTypeInfo().GetDeclaredNestedType("RTDynamicMethod");
 			return method is DynamicMethod || (typeInfoRTDynamicMethod?.IsAssignableFrom(method.GetType().GetTypeInfo()) ?? false);
 		}

src/CommunityToolkit/Xamarin.CommunityToolkit/Views/TabView/LayoutExtensions.shared.cs

@@ -1,10 +1,16 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using Xamarin.Forms;
 
 namespace Xamarin.CommunityToolkit.UI.Views
 {
 	public static class LayoutExtensions
 	{
-		public static IReadOnlyList<Element> GetChildren(this ILayoutController source) => source.Children;
+		public static IReadOnlyList<Element> GetChildren(this ILayoutController source)
+		{
+			_ = source ?? throw new ArgumentNullException(nameof(source));
+
+			return source.Children;
+		}
 	}
 }