From a9301c922005edd38a0ba6d1ca680d24c33a6542 Mon Sep 17 00:00:00 2001
From: Yunus Emre Kalkan <emre.kalkan@volosoft.com>
Date: Mon, 13 May 2019 12:21:08 +0300
Subject: [PATCH] Dynamic forms: nullable enum

---
 .../Form/AbpSelectTagHelperService.cs          | 18 ++++++++++++++----
 .../Pages/Components/DynamicForms.cshtml.cs    |  4 ++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelperService.cs
index b07100497e..46ac3a8e90 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelperService.cs
+++ b/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;
         }
diff --git a/framework/test/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.Demo/Pages/Components/DynamicForms.cshtml.cs b/framework/test/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.Demo/Pages/Components/DynamicForms.cshtml.cs
index 276f760a27..adfd91c688 100644
--- a/framework/test/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.Demo/Pages/Components/DynamicForms.cshtml.cs
+++ b/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")]