Avoid unneeded Dictionary operations

src/Umbraco.Core/Collections/ObservableDictionary.cs

@@ -160,9 +160,9 @@ protected override void InsertItem(int index, TValue item)
 
         if (index != Count)
         {
-            foreach (TKey k in Indecies.Keys.Where(k => Indecies[k] >= index).ToList())
+            foreach (KeyValuePair<TKey, int> largerOrEqualToIndex in Indecies.Where(kvp => kvp.Value >= index))
             {
-                Indecies[k]++;
+                Indecies[largerOrEqualToIndex.Key] = largerOrEqualToIndex.Value + 1;
             }
         }
 
@@ -185,9 +185,9 @@ protected override void RemoveItem(int index)
 
         Indecies.Remove(key);
 
-        foreach (TKey k in Indecies.Keys.Where(k => Indecies[k] > index).ToList())
+        foreach (KeyValuePair<TKey, int> largerThanIndex in Indecies.Where(kvp => kvp.Value > index))
         {
-            Indecies[k]--;
+            Indecies[largerThanIndex.Key] = largerThanIndex.Value - 1;
         }
     }
 

src/Umbraco.Core/Models/Content.cs

@@ -197,7 +197,7 @@ public IEnumerable<string>? EditedCultures
 
     /// <inheritdoc />
     [IgnoreDataMember]
-    public IEnumerable<string> PublishedCultures => _publishInfos?.Keys ?? Enumerable.Empty<string>();
+    public IEnumerable<string> PublishedCultures => _publishInfos?.Keys ?? [];
 
     /// <inheritdoc />
     public bool IsCulturePublished(string culture)

src/Umbraco.Core/Models/Navigation/NavigationNode.cs

@@ -39,9 +39,6 @@ public void AddChild(ConcurrentDictionary<Guid, NavigationNode> navigationStruct
         child.SortOrder = _children.Count;
 
         _children.Add(childKey);
-
-        // Update the navigation structure
-        navigationStructure[childKey] = child;
     }
 
     public void RemoveChild(ConcurrentDictionary<Guid, NavigationNode> navigationStructure, Guid childKey)
@@ -53,8 +50,5 @@ public void RemoveChild(ConcurrentDictionary<Guid, NavigationNode> navigationStr
 
         _children.Remove(childKey);
         child.Parent = null;
-
-        // Update the navigation structure
-        navigationStructure[childKey] = child;
     }
 }

src/Umbraco.Core/Services/LocalizedTextService.cs

@@ -361,10 +361,7 @@
                 result.TryAdd(dictionaryKey, key.Value);
             }
 
-            if (!overallResult.ContainsKey(areaAlias))
-            {
-                overallResult.Add(areaAlias, result);
-            }
+            overallResult.TryAdd(areaAlias, result);
         }
 
         // Merge English Dictionary

src/Umbraco.Infrastructure/Persistence/Repositories/Implement/MemberTypeRepository.cs

@@ -228,19 +228,11 @@ private void EnsureExplicitDataTypeForBuiltInProperties(IContentTypeBase memberT
             ConventionsHelper.GetStandardPropertyTypeStubs(_shortStringHelper);
         foreach (IPropertyType propertyType in memberType.PropertyTypes)
         {
-            if (builtinProperties.ContainsKey(propertyType.Alias))
+            // this reset's its current data type reference which will be re-assigned based on the property editor assigned on the next line
+            if (builtinProperties.TryGetValue(propertyType.Alias, out PropertyType? propDefinition))
             {
-                // this reset's its current data type reference which will be re-assigned based on the property editor assigned on the next line
-                if (builtinProperties.TryGetValue(propertyType.Alias, out PropertyType? propDefinition))
-                {
-                    propertyType.DataTypeId = propDefinition.DataTypeId;
-                    propertyType.DataTypeKey = propDefinition.DataTypeKey;
-                }
-                else
-                {
-                    propertyType.DataTypeId = 0;
-                    propertyType.DataTypeKey = default;
-                }
+                propertyType.DataTypeId = propDefinition.DataTypeId;
+                propertyType.DataTypeKey = propDefinition.DataTypeKey;
             }
         }
     }

src/Umbraco.Infrastructure/Persistence/Repositories/Implement/PublishStatusRepository.cs

@@ -1,6 +1,4 @@
 using NPoco;
-using Umbraco.Cms.Core.DeliveryApi;
-using Umbraco.Cms.Core.Media.EmbedProviders;
 using Umbraco.Cms.Core.Models;
 using Umbraco.Cms.Core.Persistence.Repositories;
 using Umbraco.Cms.Infrastructure.Persistence.Dtos;
@@ -67,7 +65,7 @@ public async Task<ISet<string>> GetPublishStatusAsync(Guid documentKey, Cancella
         List<PublishStatusDto>? databaseRecords = await Database.FetchAsync<PublishStatusDto>(sql);
 
         IDictionary<Guid, ISet<string>> result = Map(databaseRecords);
-        return result.ContainsKey(documentKey) ? result[documentKey] : new HashSet<string>();
+        return result.TryGetValue(documentKey, out ISet<string>? value) ? value : new HashSet<string>();
     }
 
     public async Task<IDictionary<Guid, ISet<string>>> GetDescendantsOrSelfPublishStatusAsync(Guid rootDocumentKey, CancellationToken cancellationToken)
@@ -98,7 +96,7 @@ private IDictionary<Guid, ISet<string>> Map(List<PublishStatusDto> databaseRecor
                 x=> (ISet<string>) x.Where(x=> IsPublished(x)).Select(y=>y.IsoCode).ToHashSet());
     }
 
-    private bool IsPublished(PublishStatusDto publishStatusDto)
+    private static bool IsPublished(PublishStatusDto publishStatusDto)
     {
         switch ((ContentVariation)publishStatusDto.ContentTypeVariation)
         {
@@ -112,7 +110,7 @@ private bool IsPublished(PublishStatusDto publishStatusDto)
         }
     }
 
-    private class PublishStatusDto
+    private sealed class PublishStatusDto
     {
 
         public const string DocumentVariantPublishStatusColumnName = "variantPublished";
@@ -133,5 +131,4 @@ private class PublishStatusDto
         [Column(DocumentVariantPublishStatusColumnName)]
         public bool DocumentVariantPublishStatus  { get; set; }
     }
-
 }

src/Umbraco.Web.Common/Helpers/OAuthOptionsHelper.cs

@@ -1,6 +1,7 @@
 using Microsoft.AspNetCore.Authentication;
 using Microsoft.AspNetCore.Authentication.OAuth;
 using Microsoft.Extensions.Options;
+using Microsoft.Extensions.Primitives;
 using Umbraco.Cms.Core.Configuration.Models;
 using Umbraco.Extensions;
 
@@ -14,7 +15,7 @@ public class OAuthOptionsHelper
 {
     // https://datatracker.ietf.org/doc/html/rfc6749#section-4.1.2.1
     // we omit "state" and "error_uri" here as it hold no value in determining the message to display to the user
-    private static readonly IReadOnlyCollection<string> _oathCallbackErrorParams = new string[] { "error", "error_description" };
+    private static readonly string[] _oathCallbackErrorParams = ["error", "error_description"];
 
     private readonly IOptions<SecuritySettings> _securitySettings;
 
@@ -43,7 +44,7 @@ private Task HandleResponseWithDefaultUmbracoRedirect(HandleRequestContext<Remot
         SetUmbracoRedirectWithFilteredParams(context, providerFriendlyName, eventName)
             .HandleResponse();
 
-        return Task.FromResult(0);
+        return Task.CompletedTask;
     }
 
     /// <summary>
@@ -60,9 +61,9 @@ public T SetUmbracoRedirectWithFilteredParams<T>(T context, string providerFrien
 
         foreach (var oathCallbackErrorParam in _oathCallbackErrorParams)
         {
-            if (context.Request.Query.ContainsKey(oathCallbackErrorParam))
+            if (context.Request.Query.TryGetValue(oathCallbackErrorParam, out StringValues paramValue))
             {
-                callbackPath = callbackPath.AppendQueryStringToUrl($"{oathCallbackErrorParam}={context.Request.Query[oathCallbackErrorParam]}");
+                callbackPath = callbackPath.AppendQueryStringToUrl($"{oathCallbackErrorParam}={paramValue}");
             }
         }