fixes and feedback

Author: dariatiurina

src/Components/QuickGrid/Microsoft.AspNetCore.Components.QuickGrid/src/QuickGrid.razor

@@ -77,11 +77,11 @@
     private void RenderPlaceholderRow(RenderTreeBuilder __builder, PlaceholderContext placeholderContext)
     {
         <tr aria-rowindex="@(placeholderContext.Index + 1)">
-            @foreach (var col in _columns)
+            @foreach (var col in _columns)  
             {
                 var hasCustomPlaceholder = col.PlaceholderTemplate is not null;
-                var placeholderClass = hasCustomPlaceholder ? "" : "grid-cell-placeholder";
-                <td class="@placeholderClass @ColumnClass(col)" @key="@col">@{ col.RenderPlaceholderContent(__builder, placeholderContext); }</td>
+                var placeholderClass = hasCustomPlaceholder ? "grid-cell-placeholder" : "grid-cell-placeholder default";
+                <td class="@($"{placeholderClass} {ColumnClass(col)}".Trim())" @key="@col">@{ col.RenderPlaceholderContent(__builder, placeholderContext); }</td>
             }
         </tr>
     }

src/Components/QuickGrid/Microsoft.AspNetCore.Components.QuickGrid/src/Themes/Default.css

@@ -75,7 +75,7 @@
     border-radius: 0.3rem;
 }
 
-.quickgrid[theme=default] > tbody > tr > td.grid-cell-placeholder:after {
+.quickgrid[theme=default] > tbody > tr > td.grid-cell-placeholder.default:after {
     content: '\2026';
     opacity: 0.75;
 }

src/Components/test/E2ETest/Tests/VirtualizationTest.cs

@@ -128,15 +128,16 @@ public void PlaceholdersHaveCorrectValue_Async()
         Browser.ExecuteJavaScript("const container = document.getElementById('async-container'); container.scrollTop = container.scrollHeight * 0.5;");
 
         Browser.Equal(0, () => GetItemCount());
+        int placeholderCount = GetPlaceholderCount();
         Browser.True(() => GetPlaceholderCount() > 0);
 
         Assert.Equal("\"…\"", Browser.ExecuteJavaScript<string>(@"
-        const p = document.querySelector('td.async-id');
+        const p = document.querySelector('td.grid-cell-placeholder.default');
         return p ? getComputedStyle(p, '::after').content : null;"));
         Assert.Equal("none", Browser.ExecuteJavaScript<string>(@"
-        const p = document.querySelector('td.async-second');
+        const p = document.querySelector('td.grid-cell-placeholder:not(.default)');
         return p ? getComputedStyle(p, '::after').content : null;"));
-        Browser.Equal("LOADING DATA", () => Browser.Exists(By.CssSelector(".async-second .async-placeholder")).Text);
+        Browser.Equal("LOADING DATA", () => Browser.Exists(By.CssSelector(".grid-cell-placeholder .async-placeholder")).Text);
 
         int GetItemCount() => Browser.FindElements(By.CssSelector("#async-container tbody td.async-id:not(.grid-cell-placeholder)")).Count;
         int GetPlaceholderCount() => Browser.FindElements(By.CssSelector("#async-container tbody .async-id.grid-cell-placeholder")).Count;