feat(Table): throw exception when set IsTree to true in virtualize mode (#5721)

* refactor: 更新变量名称

* refactor: 更新变量名称

* test: 更新单元测试

Author: ArgoZhang

src/BootstrapBlazor/Components/Table/Table.razor

@@ -369,13 +369,12 @@
             {
                 @if (Items != null)
                 {
-                    <Virtualize @ref="VirtualizeElement"
-                                ItemSize="RowHeight" OverscanCount="10" Items="@Items.ToList()" ChildContent="RenderRow">
+                    <Virtualize ItemSize="RowHeight" OverscanCount="10" Items="@Items.ToList()" ChildContent="RenderRow">
                     </Virtualize>
                 }
                 else
                 {
-                    <Virtualize @ref="VirtualizeElement"
+                    <Virtualize @ref="_virtualizeElement"
                                 ItemSize="RowHeight" OverscanCount="10" Placeholder="RenderPlaceholderRow"
                                 ItemsProvider="LoadItems" ItemContent="RenderRow">
                     </Virtualize>

src/BootstrapBlazor/Components/Table/Table.razor.Edit.cs

@@ -404,9 +404,9 @@ protected void OnClickCardView()
 
     private async Task QueryAsync(bool shouldRender, int? pageIndex = null, bool triggerByPagination = false)
     {
-        if (ScrollMode == ScrollMode.Virtual && VirtualizeElement != null)
+        if (ScrollMode == ScrollMode.Virtual && _virtualizeElement != null)
         {
-            await VirtualizeElement.RefreshDataAsync();
+            await _virtualizeElement.RefreshDataAsync();
         }
         else
         {

src/BootstrapBlazor/Components/Table/Table.razor.cs

@@ -38,7 +38,8 @@ public partial class Table<TItem> : ITable, IModelEqualityComparer<TItem> where
     /// <summary>
     /// 获得/设置 内置虚拟化组件实例
     /// </summary>
-    protected Virtualize<TItem>? VirtualizeElement { get; set; }
+    [NotNull]
+    private Virtualize<TItem>? _virtualizeElement = null;
 
     /// <summary>
     /// 获得 Table 组件样式表

test/UnitTest/Components/TableTest.cs

@@ -8911,9 +8911,10 @@ public async Task TestLoopQueryAsync()
 
         public RenderFragment RenderVirtualPlaceHolder() => new(builder =>
         {
-            if (ScrollMode == ScrollMode.Virtual && VirtualizeElement != null)
+            var fieldInfo = GetType().BaseType!.GetField("_virtualizeElement", BindingFlags.NonPublic | BindingFlags.Instance)!;
+            if (ScrollMode == ScrollMode.Virtual && fieldInfo.GetValue(this) is Virtualize<Foo> element)
             {
-                builder.AddContent(0, VirtualizeElement.Placeholder?.Invoke(new Microsoft.AspNetCore.Components.Web.Virtualization.PlaceholderContext()));
+                builder.AddContent(0, element.Placeholder?.Invoke(new PlaceholderContext()));
             }
         });