[DataGrid] Fix pagination when using itemprovider

src/Core.Assets/esbuild.config.mjs

@@ -1,5 +1,5 @@
 import * as esbuild from 'esbuild'
-import pkg from './package.json' assert { type: 'json' }
+import pkg from './package.json' with { type: 'json' }
 
 await esbuild.build({
     entryPoints: [ pkg.source ],

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

@@ -559,7 +559,8 @@ private async Task RefreshDataCoreAsync()
             // the current viewport. In the case where you're also paginating then it means what's conceptually on the current page.
             // TODO: This currently assumes we always want to expand the last page to have ItemsPerPage rows, but the experience might
             //       be better if we let the last page only be as big as its number of actual rows.
-            _internalGridContext.TotalItemCount = Pagination is null ? providerResult.TotalItemCount : Pagination.ItemsPerPage;
+            _internalGridContext.TotalItemCount = providerResult.TotalItemCount;
+            _internalGridContext.TotalViewItemCount = Pagination?.ItemsPerPage ?? providerResult.TotalItemCount;
 
             Pagination?.SetTotalItemCountAsync(_internalGridContext.TotalItemCount);
             if (_internalGridContext.TotalItemCount > 0)
@@ -572,7 +573,7 @@ private async Task RefreshDataCoreAsync()
             // to make sure it doesn't get out of sync with the rows being rendered.
             return new ItemsProviderResult<(int, TGridItem)>(
                  items: providerResult.Items.Select((x, i) => ValueTuple.Create(i + request.StartIndex + 2, x)),
-                 totalItemCount: _internalGridContext.TotalItemCount);
+                 totalItemCount: _internalGridContext.TotalViewItemCount);
         }
 
         return default;

src/Core/Components/DataGrid/Infrastructure/InternalGridContext.cs

@@ -17,6 +17,7 @@ internal sealed class InternalGridContext<TGridItem>
 
     public ICollection<TGridItem> Items { get; set; } = [];
     public int TotalItemCount { get; set; }
+    public int TotalViewItemCount { get; set; }
 
     public FluentDataGrid<TGridItem> Grid { get; }
     public EventCallbackSubscribable<object?> ColumnsFirstCollected { get; } = new();