fix(module: table): formatting with nullable type for table column (#487)

components/core/Helpers/Formatter.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Linq.Expressions;
 using System.Globalization;
+using AntDesign.Core.Reflection;
+using System.Collections.Generic;
 
 namespace AntDesign.Helpers
 {
@@ -19,20 +21,28 @@ namespace AntDesign.Helpers
             var p1 = Expression.Parameter(typeof(T));
             var p2 = Expression.Parameter(typeof(string));
 
+            Expression variable = p1;
             Expression body = p2;
+
+            if (TypeDefined<T>.IsNullable)
+            {
+                type = TypeDefined<T>.NullableType;
+            }
+
             if (type.IsSubclassOf(typeof(IFormattable)))
             {
                 var method = type.GetMethod("ToString", new[] { typeof(string), typeof(IFormatProvider) });
-                body = Expression.Call(Expression.Convert(p1, type), method, p2, Expression.Constant(null));
+                body = Expression.Call(Expression.Convert(variable, type), method, p2, Expression.Constant(null));
             }
             else
             {
                 var method = type.GetMethod("ToString", new[] { typeof(string) });
                 if (method != null)
                 {
-                    body = Expression.Call(Expression.Convert(p1, type), method, p2);
+                    body = Expression.Call(Expression.Convert(variable, type), method, p2);
                 }
             }
+
             return Expression.Lambda<Func<T, string, string>>(body, p1, p2).Compile();
         }
     }

components/core/Reflection/TypeDefined.cs

@@ -0,0 +1,29 @@
+using System;
+
+namespace AntDesign.Core.Reflection
+{
+    internal static class TypeDefined<T>
+    {
+        public static bool IsNullable;
+
+        public static bool IsGenericType => typeof(T).IsGenericType;
+
+        public static Type NullableType;
+
+        static TypeDefined()
+        {
+            IsNullable = IsNullableType(typeof(T));
+            NullableType = GetNullableGenericType(typeof(T));
+        }
+
+        private static bool IsNullableType(Type type)
+        {
+            return type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>);
+        }
+
+        private static Type GetNullableGenericType(Type type)
+        {
+            return IsNullableType(type) ? type.GetGenericArguments()[0] : null;
+        }
+    }
+}

site/AntBlazor.Docs/Demos/Components/Table/demo/Blazor.razor

@@ -74,7 +74,7 @@
         public int Id { get; set; }
 
         [DisplayName("Date")]
-        public DateTime Date { get; set; }
+        public DateTime? Date { get; set; }
 
         [DisplayName("Temp. (C)")]
         public int TemperatureC { get; set; }