feat: 枚举类型支持 Flags 标签

Author: ArgoZhang

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

@@ -236,13 +236,15 @@ protected override void OnParametersSet()
         ResetRules();
 
         _itemsCache = null;
+
         // 通过 Value 对集合进行赋值
-        if (PreviousValue != CurrentValueAsString)
+        var _currentValue = CurrentValueAsString;
+        if (PreviousValue != _currentValue)
         {
-            PreviousValue = CurrentValueAsString;
-            var list = CurrentValueAsString.Split(',', StringSplitOptions.RemoveEmptyEntries);
+            PreviousValue = _currentValue;
+            var list = _currentValue.Split(',', StringSplitOptions.RemoveEmptyEntries);
             SelectedItems.Clear();
-            SelectedItems.AddRange(Rows.Where(item => list.Any(i => i == item.Value)));
+            SelectedItems.AddRange(Rows.Where(item => list.Any(i => i.Trim() == item.Value)));
         }
     }
 
@@ -418,18 +420,9 @@ private async Task SetValue()
             }
             CurrentValue = (TValue)(ValueType.IsGenericType ? instance : listType.GetMethod("ToArray")!.Invoke(instance, null)!);
         }
-        else if (ValueType.IsEnum && ValueType.GetCustomAttribute<FlagsAttribute>() != null)
+        else if (ValueType.IsFlagEnum())
         {
-            var count = 0;
-            foreach (var item in SelectedItems)
-            {
-                if (Enum.TryParse(ValueType, item.Value, true, out var val))
-                {
-                    count += (int)val;
-                }
-            }
-
-            CurrentValue = (TValue)(object)count;
+            CurrentValue = (TValue?)SelectedItems.ParseFlagEnum<TValue>(ValueType);
         }
 
         if (ValidateForm == null && (Min > 0 || Max > 0))

src/BootstrapBlazor/Extensions/EnumExtensions.cs

@@ -63,11 +63,7 @@ public static List<SelectedItem> ToSelectList(this Type type, SelectedItem? addi
         if (type.IsEnum())
         {
             var t = Nullable.GetUnderlyingType(type) ?? type;
-            foreach (var field in Enum.GetNames(t))
-            {
-                var desc = Utility.GetDisplayName(t, field);
-                ret.Add(new SelectedItem(field, desc));
-            }
+            ret.AddRange(from field in Enum.GetNames(t) let desc = Utility.GetDisplayName(t, field) select new SelectedItem(field, desc));
         }
         return ret;
     }
@@ -114,4 +110,33 @@ public static bool IsEnum(this Type? type)
         }
         return ret;
     }
+
+    /// <summary>
+    /// 判断类型是否为 Flag 枚举类型
+    /// </summary>
+    /// <param name="type"></param>
+    /// <returns></returns>
+    public static bool IsFlagEnum(this Type? type) => type != null && IsEnum(type) && type.GetCustomAttribute<FlagsAttribute>() != null;
+
+    /// <summary>
+    /// 将 <see cref="IEnumerable{T}"/> 集合转换为 Flag 枚举值
+    /// </summary>
+    /// <param name="items"></param>
+    /// <param name="type"></param>
+    /// <returns></returns>
+    internal static object? ParseFlagEnum<TValue>(this IEnumerable<SelectedItem> items, Type type)
+    {
+        TValue? v = default;
+        if (type.IsFlagEnum())
+        {
+            foreach (var item in items)
+            {
+                if (Enum.TryParse(type, item.Value, true, out var val))
+                {
+                    v = (TValue)Enum.ToObject(type, Convert.ToInt32(v) | Convert.ToInt32(val));
+                }
+            }
+        }
+        return v;
+    }
 }

src/BootstrapBlazor/Utils/Utility.cs

@@ -830,6 +830,10 @@ public static string Format(object? source, IFormatProvider provider)
                 }
             }
         }
+        else if (typeValue.IsFlagEnum())
+        {
+            ret = value!.ToString();
+        }
         return ret;
     }