Refine logic that determines if the DataGrid data needs to be reloaded (#3864)

Author: vnbaaij

examples/Demo/Shared/Microsoft.FluentUI.AspNetCore.Components.xml

@@ -1241,6 +1241,12 @@
             If not specified, the default header template includes the <see cref="P:Microsoft.FluentUI.AspNetCore.Components.ColumnBase`1.Title" /> along with any applicable sort indicators and options buttons.
             </summary>
         </member>
+        <member name="P:Microsoft.FluentUI.AspNetCore.Components.ColumnBase`1.HeaderCellTitleTemplate">
+            <summary>
+            Gets or sets a template for the title content of this column's header cell.
+            If not specified, the default header template includes the <see cref="P:Microsoft.FluentUI.AspNetCore.Components.ColumnBase`1.Title" />.
+            </summary>
+        </member>
         <member name="P:Microsoft.FluentUI.AspNetCore.Components.ColumnBase`1.ColumnOptions">
              <summary>
              If specified, indicates that this column has this associated options UI. A button to display this
@@ -1350,6 +1356,14 @@
             respecting that option.
             </summary>
         </member>
+        <member name="P:Microsoft.FluentUI.AspNetCore.Components.ColumnBase`1.HeaderTitleContent">
+            <summary>
+            Gets or sets a <see cref="T:Microsoft.AspNetCore.Components.RenderFragment" /> that will be rendered for this column's header title.
+            This allows derived components to change the header title output. However, derived components are then
+            responsible for using <see cref="P:Microsoft.FluentUI.AspNetCore.Components.ColumnBase`1.HeaderCellTitleTemplate" /> within that new output if they want to continue
+            respecting that option.
+            </summary>
+        </member>
         <member name="M:Microsoft.FluentUI.AspNetCore.Components.ColumnBase`1.IsSortableByDefault">
              <summary>
              Gets a value indicating whether this column should act as sortable if no value was set for the
@@ -2262,6 +2276,12 @@
             </summary>
             <returns></returns>
         </member>
+        <member name="M:Microsoft.FluentUI.AspNetCore.Components.FluentDataGrid`1.ComputeItemsHash(System.Collections.Generic.IEnumerable{`0},System.Int32)">
+            <summary>
+            Computes a hash code for the given items.
+            To limit the effect on performance, only the given maximum number (default 250) of items will be considered.
+            </summary>
+        </member>
         <member name="P:Microsoft.FluentUI.AspNetCore.Components.FluentDataGridCell`1.Item">
             <summary>
             Gets or sets the reference to the item that holds this cell's values.

examples/Demo/Shared/Pages/Menu/MenuPage.razor

@@ -40,7 +40,7 @@
     <p>
         With version 4.9.4 of the library, we introduced the <code>FluentMenuProvider</code> component. The Menu component has been updated to use this provider.
         The <code>&lt;FluentMenuProvider /&gt;</code> needs to be placed at the <b>bottom</b> of your HTML page (just like the other <b>...Providers</b> components).
-        It will renders all menus (and menu items) at the provider location in the HTML structure. This allows for menus to appear <b>on top</b> other components.
+        It will render all menus (and menu items) at the provider location in the HTML structure. This allows for menus to appear <b>above</b> of other components.
     </p>
     <p>
         You can disable this feature by adding the <code>UseMenuService</code> parameter (with a value of "false") to you FluentMenu component. In this case, the menu will be rendered at the location it is placed at in the page.

src/Core/Components/DataGrid/FluentDataGrid.razor.cs

@@ -374,6 +374,7 @@ public partial class FluentDataGrid<TGridItem> : FluentComponentBase, IHandleEve
     // things have changed, and to discard earlier load attempts that were superseded.
     private PaginationState? _lastRefreshedPaginationState;
     private IQueryable<TGridItem>? _lastAssignedItems;
+    private int _lastAssignedItemsHashCode;
     private GridItemsProvider<TGridItem>? _lastAssignedItemsProvider;
     private CancellationTokenSource? _pendingDataLoadCancellationTokenSource;
 
@@ -434,14 +435,18 @@ protected override Task OnParametersSetAsync()
             throw new InvalidOperationException($"FluentDataGrid cannot use both {nameof(Virtualize)} and {nameof(MultiLine)} at the same time.");
         }
 
+        var currentItemsHash = FluentDataGrid<TGridItem>.ComputeItemsHash(Items);
+        var itemsChanged = currentItemsHash != _lastAssignedItemsHashCode;
+
         // Perform a re-query only if the data source or something else has changed
-        var dataSourceHasChanged = !Equals(Items, _lastAssignedItems) || !Equals(ItemsProvider, _lastAssignedItemsProvider);
+        var dataSourceHasChanged = itemsChanged || !Equals(ItemsProvider, _lastAssignedItemsProvider);
         if (dataSourceHasChanged)
         {
             _scope?.Dispose();
             _scope = ScopeFactory.CreateAsyncScope();
             _lastAssignedItemsProvider = ItemsProvider;
             _lastAssignedItems = Items;
+            _lastAssignedItemsHashCode = currentItemsHash;
             _asyncQueryExecutor = AsyncQueryExecutorSupplier.GetAsyncQueryExecutor(_scope.Value.ServiceProvider, Items);
         }
 
@@ -1102,4 +1107,31 @@ public async Task ResetColumnWidthsAsync()
             await Module.InvokeVoidAsync("resetColumnWidths", _gridReference);
         }
     }
+
+    /// <summary>
+    /// Computes a hash code for the given items.
+    /// To limit the effect on performance, only the given maximum number (default 250) of items will be considered.
+    /// </summary>
+    private static int ComputeItemsHash(IEnumerable<TGridItem>? items, int maxItems = 250)
+    {
+        if (items == null)
+        {
+            return 0;
+        }
+        unchecked
+        {
+            var hash = 19;
+            var count = 0;
+            foreach (var item in items)
+            {
+                if (++count > maxItems)
+                {
+                    break;
+                }
+                hash = (hash * 31) + (item?.GetHashCode() ?? 0);
+            }
+            return hash;
+        }
+    }
 }
+