- 增加 [Description] 元数据注释，优先级低于 c# 代码注释；

FreeSql/FreeSql.xml

@@ -2901,6 +2901,13 @@
             AsType, Ctor, ClearData 三处地方需要重新加载
             </summary>
         </member>
+        <member name="M:FreeSql.Internal.CommonUtils.GetPropertyCommentByDescriptionAttribute(System.Type)">
+            <summary>
+            动态读取 DescriptionAttribute 注释文本
+            </summary>
+            <param name="type"></param>
+            <returns></returns>
+        </member>
         <member name="M:FreeSql.Internal.CommonUtils.GetProperyCommentBySummary(System.Type)">
             <summary>
             通过属性的注释文本，通过 xml 读取

FreeSql/Internal/CommonUtils.cs

@@ -371,6 +371,48 @@ namespace FreeSql.Internal
             return iidx == 1 ? sb.Remove(0, 5).Remove(sb.Length - 1, 1).ToString() : sb.Remove(0, 4).ToString();
         }
 
+        /// <summary>
+        /// 动态读取 DescriptionAttribute 注释文本
+        /// </summary>
+        /// <param name="type"></param>
+        /// <returns></returns>
+        public static Dictionary<string, string> GetPropertyCommentByDescriptionAttribute(Type type)
+        {
+            var dic = new Dictionary<string, string>();
+            GetDydesc(null); //class注释
+
+            var props = type.GetPropertiesDictIgnoreCase().Values;
+            foreach (var prop in props)
+                GetDydesc(prop);
+
+            return dic;
+
+            void GetDydesc(PropertyInfo prop)
+            {
+                object[] attrs = null;
+                try
+                {
+                    attrs = prop == null ? 
+                        type.GetCustomAttributes(false).ToArray() : 
+                        prop.GetCustomAttributes(false).ToArray(); //.net core 反射存在版本冲突问题，导致该方法异常
+                }
+                catch { }
+
+                var dyattr = attrs?.Where(a => {
+                    return ((a as Attribute)?.TypeId as Type)?.Name == "DescriptionAttribute";
+                }).FirstOrDefault();
+                if (dyattr != null)
+                {
+                    var valueProp = dyattr.GetType().GetProperties().Where(a => a.PropertyType == typeof(string)).FirstOrDefault();
+                    var comment = valueProp?.GetValue(dyattr, null)?.ToString();
+                    if (string.IsNullOrEmpty(comment) == false)
+                        dic.Add(prop == null ? 
+                            "" : 
+                            prop.Name, comment);
+                }
+            }
+        }
+
         /// <summary>
         /// 通过属性的注释文本，通过 xml 读取
         /// </summary>
@@ -378,6 +420,8 @@ namespace FreeSql.Internal
         /// <returns>Dict：key=属性名，value=注释</returns>
         public static Dictionary<string, string> GetProperyCommentBySummary(Type type)
         {
+            if (type.Assembly.IsDynamic) return null;
+            //动态生成的程序集，访问不了 Assembly.Location/Assembly.CodeBase
             var regex = new Regex(@"\.(dll|exe)", RegexOptions.IgnoreCase);
             var xmlPath = regex.Replace(type.Assembly.Location, ".xml");
             if (File.Exists(xmlPath) == false)

FreeSql/Internal/UtilsExpressionTree.cs

@@ -69,7 +69,10 @@ namespace FreeSql.Internal
             var propsLazy = new List<NaviteTuple<PropertyInfo, bool, bool, MethodInfo, MethodInfo>>();
             var propsNavObjs = new List<PropertyInfo>();
             var propsComment = CommonUtils.GetProperyCommentBySummary(entity);
+            var propsCommentByDescAttr = CommonUtils.GetPropertyCommentByDescriptionAttribute(entity);
             trytb.Comment = propsComment != null && propsComment.TryGetValue("", out var tbcomment) ? tbcomment : "";
+            if (string.IsNullOrEmpty(trytb.Comment) && propsCommentByDescAttr != null && propsCommentByDescAttr.TryGetValue("", out tbcomment)) trytb.Comment = tbcomment;
+
             var columnsList = new List<ColumnInfo>();
             foreach (var p in trytb.Properties.Values)
             {
@@ -148,6 +151,9 @@ namespace FreeSql.Internal
                 };
                 if (propsComment != null && propsComment.TryGetValue(p.Name, out var trycomment))
                     col.Comment = trycomment;
+                if (string.IsNullOrEmpty(col.Comment) && propsCommentByDescAttr != null && propsCommentByDescAttr.TryGetValue(p.Name, out trycomment))
+                    col.Comment = trycomment;
+
                 if (colattr.IsIgnore)
                 {
                     trytb.ColumnsByCsIgnore.Add(p.Name, col);