添加SelectToday参数，用于当组件有设定最小值时，让其可以默认当天

添加SelectToday参数，用于当组件有设定最小值时，让其可以默认当天

Author: Tony-ST0754

src/BootstrapBlazor/Components/DateTimePicker/DateTimePicker.razor.cs

@@ -287,6 +287,14 @@ public string? Format
     [Parameter]
     public bool ShowHolidays { get; set; }
 
+    /// <summary>
+    /// <para lang="zh">获得/设置 是否选择今天 默认 false</para>
+    /// <para lang="en">Gets or sets Whether to Select Today. Default is false</para>
+    /// </summary>
+    /// <remarks>当 Value 值为 null 且组件设置了 <see cref="DateTimePicker{TValue}.MinValue"/> 的值是，当前选中时间为当天， <see cref="DateTimePicker{TValue}.MinValue"/> 不为空类型时此参数生效</remarks>
+    [Parameter]
+    public bool SelectToday { get; set; }
+
     /// <summary>
     /// <para lang="zh">获取/设置 获得自定义禁用日期回调方法，默认 null 内部默认启用数据缓存 可通过 <see cref="EnableDisabledDaysCache"/> 参数关闭</para>
     /// <para lang="en">Gets or sets Callback Method to Get Custom Disabled Days. Default is null. Internal Default Enable Data Cache. Can be Closed via <see cref="EnableDisabledDaysCache"/> Parameter</para>
@@ -373,7 +381,7 @@ protected override void OnParametersSet()
         }
         else
         {
-            SelectedValue = Value == null ? (MinValue ?? DateTime.MinValue) : (DateTime)(object)Value;
+            SelectedValue = Value == null ? ((SelectToday ? DateTime.Today : MinValue) ?? DateTime.MinValue) : (DateTime)(object)Value;
         }
 
         if (MinValue > SelectedValue)

test/UnitTest/Components/DateTimePickerTest.cs

@@ -296,6 +296,40 @@ public void MinValue_Ok()
         Assert.Equal(DateTime.Today, cut.Instance.Value.Date);
     }
 
+    [Fact]
+    public void SelectToday_Ok()
+    {
+        var cut = Context.Render<DateTimePicker<DateTime?>>(builder =>
+        {
+            builder.Add(a => a.Value, null);
+            builder.Add(a => a.SelectToday, true);
+        });
+        Assert.Null(cut.Instance.Value);
+
+        // 点击确定
+        var buttons = cut.FindAll(".picker-panel-footer button");
+        cut.InvokeAsync(() => buttons[1].Click());
+
+        Assert.Equal(DateTime.Today, cut.Instance.Value);
+
+
+        cut.Render(pb =>
+        {
+            pb.Add(a => a.MinValue, DateTime.Today.AddDays(-1));
+            pb.Add(a => a.SelectToday, true);
+        });
+        Assert.Equal(DateTime.Today, cut.Instance.Value);
+       
+        cut.Render(pb =>
+        {
+            pb.Add(a => a.Value, DateTime.MinValue);
+            pb.Add(a => a.MinValue, DateTime.Today.AddDays(-1));
+            pb.Add(a => a.SelectToday, false);
+        });
+        Assert.Equal(DateTime.Today.AddDays(-1).Date, cut.Instance.Value?.Date);
+
+    }
+
     [Fact]
     public void OnTimeChanged_Ok()
     {