Dynamic forms: nullable enum

framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelperService.cs

@@ -187,13 +187,23 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Form
         {
             var localizer = _tagHelperLocalizer.GetLocalizer(explorer);
 
-            var selectItems = explorer.ModelType.GetTypeInfo().GetMembers(BindingFlags.Public | BindingFlags.Static)
+            var selectItems = new List<SelectListItem>();
+            var isNullableType = Nullable.GetUnderlyingType(explorer.ModelType) != null;
+            var enumType = explorer.ModelType;
+
+            if (isNullableType)
+            {
+                enumType = Nullable.GetUnderlyingType(explorer.ModelType);
+                selectItems.Add(new SelectListItem());
+            }
+
+            selectItems.AddRange(enumType.GetTypeInfo().GetMembers(BindingFlags.Public | BindingFlags.Static)
                 .Select((t, i) => 
                     new SelectListItem
                     {
-                        Value = ((int) Enum.Parse(explorer.ModelType, t.Name)).ToString(),
-                        Text = GetLocalizedPropertyName(localizer, explorer.ModelType, t.Name)
-                    }).ToList();
+                        Value = ((int) Enum.Parse(enumType, t.Name)).ToString(),
+                        Text = GetLocalizedPropertyName(localizer, enumType, t.Name)
+                    }).ToList());
 
             return selectItems;
         }

framework/test/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.Demo/Pages/Components/DynamicForms.cshtml.cs

@@ -123,6 +123,10 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.Demo.Pages.Components
             [Display(Name = "My Car Type")]
             public CarType MyCarType { get; set; }
 
+            [Required]
+            [Display(Name = "My Car Type Nullable")]
+            public CarType? MyCarTypeNullable { get; set; }
+
             [Required]
             [AbpRadioButton(Inline = true)]
             [Display(Name = "Your Car Type")]