codefirst 根据代码注释，迁移到数据库备注

FreeSql/FreeSql.xml

@@ -2270,6 +2270,13 @@
             <param name="database"></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
+            </summary>
+            <param name="type"></param>
+            <returns>Dict：key=属性名，value=注释</returns>
+        </member>
         <member name="P:FreeSql.Internal.Model.TableRef.RefMiddleEntityType">
             <summary>
             中间表，多对多

FreeSql/Internal/CommonUtils.cs

@@ -8,11 +8,14 @@ using System.Collections;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Data.Common;
+using System.IO;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Text;
 using System.Threading.Tasks;
+using System.Xml;
+using System.Xml.XPath;
 
 namespace FreeSql.Internal {
 	public abstract class CommonUtils {
@@ -239,6 +242,36 @@ namespace FreeSql.Internal {
 			return iidx == 1 ? sb.Remove(0, 5).Remove(sb.Length - 1, 1).ToString() : sb.Remove(0, 4).ToString();
 		}
 
+		/// <summary>
+		/// 通过属性的注释文本，通过 xml 读取
+		/// </summary>
+		/// <param name="type"></param>
+		/// <returns>Dict：key=属性名，value=注释</returns>
+		public static Dictionary<string, string> GetProperyCommentBySummary(Type type) {
+			var xmlPath = type.Assembly.Location.Replace(".dll", ".xml");
+			if (File.Exists(xmlPath) == false) return null;
+
+			var dic = new Dictionary<string, string>();
+			var className = type.IsNested ? $"{type.Namespace}.{type.DeclaringType.Name}.{type.Name}" : $"{type.Namespace}.{type.Name}";
+			var sReader = new StringReader(File.ReadAllText(xmlPath));
+			using (var xmlReader = XmlReader.Create(sReader)) {
+				var xpath = new XPathDocument(xmlReader);
+				var xmlNav = xpath.CreateNavigator();
+
+				var props = type.GetProperties();
+				foreach (var prop in props) {
+					var node = xmlNav.SelectSingleNode($"/doc/members/member[@name='P:{className}.{prop.Name}']/summary");
+					if (node == null) continue;
+					var comment = node.InnerXml.Trim(' ', '\r', '\n', '\t');
+					if (string.IsNullOrEmpty(comment)) continue;
+
+					dic.Add(prop.Name, comment);
+				}
+			}
+
+			return dic;
+		}
+
 		public static void PrevReheatConnectionPool(ObjectPool<DbConnection> pool, int minPoolSize) {
 			if (minPoolSize <= 0) minPoolSize = Math.Min(5, pool.Policy.PoolSize);
 			if (minPoolSize > pool.Policy.PoolSize) minPoolSize = pool.Policy.PoolSize;

FreeSql/Internal/Model/ColumnInfo.cs

@@ -10,6 +10,7 @@ namespace FreeSql.Internal.Model {
 		public string CsName { get; set; }
 		public Type CsType { get; set; }
 		public ColumnAttribute Attribute { get; set; }
+		public string Comment { get; internal set; }
 
 		static ConcurrentDictionary<ColumnInfo, Func<object, object>> _dicGetMapValue = new ConcurrentDictionary<ColumnInfo, Func<object, object>>();
 		public object GetMapValue(object obj) {

FreeSql/Internal/UtilsExpressionTree.cs

@@ -56,6 +56,7 @@ namespace FreeSql.Internal {
 			if (tbattr != null) trytb.DisableSyncStructure = tbattr.DisableSyncStructure;
 			var propsLazy = new List<(PropertyInfo, bool, bool)>();
 			var propsNavObjs = new List<PropertyInfo>();
+			var propsComment = CommonUtils.GetProperyCommentBySummary(entity);
 			foreach (var p in trytb.Properties.Values) {
 				var setMethod = trytb.Type.GetMethod($"set_{p.Name}");
 				var colattr = common.GetEntityColumnAttribute(entity, p);
@@ -124,6 +125,8 @@ namespace FreeSql.Internal {
 					CsType = p.PropertyType,
 					Attribute = colattr
 				};
+				if (propsComment != null && propsComment.TryGetValue(p.Name, out var trycomment))
+					col.Comment = trycomment;
 				if (colattr.IsIgnore) {
 					trytb.ColumnsByCsIgnore.Add(p.Name, col);
 					continue;