feat(Select): add DefaultVirtualizeItemText parameter (#2020)

* feat: 虚拟化时支持绑定值

* feat: 支持虚拟化给定默认值

* test: 增加单元测试

* refactor: 更新代码

* test: 更新单元测试

* chore: bump version 7.9.4-beta01

Author: ArgoZhang

src/BootstrapBlazor/BootstrapBlazor.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Razor">
 
   <PropertyGroup>
-    <Version>7.9.3</Version>
+    <Version>7.9.4-beta01</Version>
   </PropertyGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net5.0'">

src/BootstrapBlazor/Components/Select/Select.razor.cs

@@ -151,6 +151,13 @@ public partial class Select<TValue> : ISelect
     [Parameter]
     public int OverscanCount { get; set; } = 4;
 
+    /// <summary>
+    /// 获得/设置 默认文本 <see cref="IsVirtualize"/> 时生效 默认 null
+    /// </summary>
+    /// <remarks>开启 <see cref="IsVirtualize"/> 并且通过 <see cref="OnQueryAsync"/> 提供数据源时，由于渲染时还未调用或者调用后数据集未包含 <see cref="DisplayBase{TValue}.Value"/> 选项值，此时使用 DefaultText 值渲染</remarks>
+    [Parameter]
+    public string? DefaultVirtualizeItemText { get; set; }
+
     [NotNull]
     private Virtualize<SelectedItem>? VirtualizeElement { get; set; }
 
@@ -254,14 +261,16 @@ protected override bool TryParseValueFromString(string value, [MaybeNullWhen(fal
 
     private bool TryParseSelectItem(string value, [MaybeNullWhen(false)] out TValue result, out string? validationErrorMessage)
     {
-        SelectedItem = (VirtualItems ?? DataSource).FirstOrDefault(i => i.Value == value);
+        SelectedItem = (VirtualItems ?? DataSource).FirstOrDefault(i => i.Value == value) ?? GetVirtualizeItem();
 
         // support SelectedItem? type
         result = SelectedItem != null ? (TValue)(object)SelectedItem : default;
         validationErrorMessage = "";
         return SelectedItem != null;
     }
 
+    private SelectedItem? GetVirtualizeItem() => OnQueryAsync == null ? null : ValueType == typeof(SelectedItem) ? (SelectedItem)(object)Value : new SelectedItem(CurrentValueAsString, DefaultVirtualizeItemText ?? CurrentValueAsString);
+
     private void ResetSelectedItem()
     {
         DataSource.Clear();
@@ -270,14 +279,16 @@ private void ResetSelectedItem()
         {
             DataSource.AddRange(Items);
             DataSource.AddRange(Children);
+
             if (VirtualItems != null)
             {
                 DataSource.AddRange(VirtualItems);
             }
 
             SelectedItem = DataSource.FirstOrDefault(i => i.Value.Equals(CurrentValueAsString, StringComparison))
                 ?? DataSource.FirstOrDefault(i => i.Active)
-                ?? DataSource.FirstOrDefault();
+                ?? DataSource.FirstOrDefault()
+                ?? GetVirtualizeItem();
 
             if (SelectedItem != null)
             {
@@ -365,14 +376,14 @@ private async Task SelectedItemChanged(SelectedItem item)
             item.Active = true;
             SelectedItem = item;
 
-            // 触发 StateHasChanged
-            CurrentValueAsString = item.Value;
-
             // 触发 SelectedItemChanged 事件
             if (OnSelectedItemChanged != null)
             {
                 await OnSelectedItemChanged(SelectedItem);
             }
+
+            // 触发 StateHasChanged
+            CurrentValueAsString = item.Value;
         }
     }
 

test/UnitTest/Components/SelectTest.cs

@@ -608,6 +608,86 @@ public void IsVirtualize_OnQueryAsync()
         });
     }
 
+    [Fact]
+    public void IsVirtualize_BindValue()
+    {
+        var value = new SelectedItem("3", "Test 3");
+        var cut = Context.RenderComponent<Select<SelectedItem>>(pb =>
+        {
+            pb.Add(a => a.Value, value);
+            pb.Add(a => a.IsVirtualize, true);
+            pb.Add(a => a.ValueChanged, EventCallback.Factory.Create<SelectedItem>(this, new Action<SelectedItem>(item =>
+            {
+                value = item;
+            })));
+            pb.Add(a => a.OnQueryAsync, option =>
+            {
+                return Task.FromResult(new QueryData<SelectedItem>()
+                {
+                    Items = new SelectedItem[]
+                    {
+                        new SelectedItem("1", "Test1"),
+                        new SelectedItem("2", "Test2")
+                    },
+                    TotalCount = 2
+                });
+            });
+        });
+
+        cut.InvokeAsync(() =>
+        {
+            var input = cut.Find(".form-select");
+            Assert.Equal("Test 3", input.GetAttribute("value"));
+        });
+        cut.Contains("Test 3");
+        var select = cut.Instance;
+        Assert.Equal("3", select.Value?.Value);
+
+        cut.InvokeAsync(() =>
+        {
+            var item = cut.Find(".dropdown-item");
+            item.Click();
+            Assert.Equal("1", value.Value);
+
+            var input = cut.Find(".form-select");
+            Assert.Equal("Test1", input.GetAttribute("value"));
+        });
+    }
+
+    [Fact]
+    public void IsVirtualize_DefaultVirtualizeItemText()
+    {
+        string value = "3";
+        var cut = Context.RenderComponent<Select<string>>(pb =>
+        {
+            pb.Add(a => a.IsVirtualize, true);
+            pb.Add(a => a.DefaultVirtualizeItemText, "Test 3");
+            pb.Add(a => a.Value, value);
+            pb.Add(a => a.ValueChanged, EventCallback.Factory.Create<string>(this, new Action<string>(item =>
+            {
+                value = item;
+            })));
+            pb.Add(a => a.OnQueryAsync, option =>
+            {
+                return Task.FromResult(new QueryData<SelectedItem>()
+                {
+                    Items = new SelectedItem[]
+                    {
+                        new SelectedItem("1", "Test1"),
+                        new SelectedItem("2", "Test2")
+                    },
+                    TotalCount = 2
+                });
+            });
+        });
+
+        cut.InvokeAsync(() =>
+        {
+            var input = cut.Find(".form-select");
+            Assert.Equal("Test 3", input.GetAttribute("value"));
+        });
+    }
+
     [Fact]
     public void LoadItems_Ok()
     {