diff --git a/OpenAuth.App/OrgManagerApp.cs b/OpenAuth.App/OrgManagerApp.cs
index 337cb082..7b5562af 100644
--- a/OpenAuth.App/OrgManagerApp.cs
+++ b/OpenAuth.App/OrgManagerApp.cs
@@ -43,6 +43,8 @@ namespace OpenAuth.App
                 UnitWork.Update(a);
             }
 
+            UnitWork.Save();
+
             return org.Id;
         }
 
diff --git a/OpenAuth.Mvc/Controllers/OrgManagerController.cs b/OpenAuth.Mvc/Controllers/OrgManagerController.cs
index 14066c4f..cd69f213 100644
--- a/OpenAuth.Mvc/Controllers/OrgManagerController.cs
+++ b/OpenAuth.Mvc/Controllers/OrgManagerController.cs
@@ -18,13 +18,7 @@ namespace OpenAuth.Mvc.Controllers
         {
             return View();
         }
-        public ActionResult Assign(string firstId, string key)
-        {
-            ViewBag.FirstId = firstId;
-            ViewBag.ModuleType = key;
-            return View();
-        }
-
+       
         public string LoadForUser(string firstId)
         {
             var orgs = OrgApp.LoadForUser(firstId);
@@ -72,7 +66,6 @@ namespace OpenAuth.Mvc.Controllers
 
        /// <summary>
         /// 删除指定ID的组织
-        /// <para>Id为逗号分开的字符串</para>
         /// </summary>
         /// <returns>System.String.</returns>
         [HttpPost]
diff --git a/OpenAuth.Mvc/Controllers/UserSessionController.cs b/OpenAuth.Mvc/Controllers/UserSessionController.cs
index 1c1a2e72..c0b71eee 100644
--- a/OpenAuth.Mvc/Controllers/UserSessionController.cs
+++ b/OpenAuth.Mvc/Controllers/UserSessionController.cs
@@ -78,7 +78,13 @@ namespace OpenAuth.Mvc.Controllers
             {
                 var org = user.Orgs.SingleOrDefault(u => u.Id == orgId);
                 if (org == null)
-                    throw new Exception("未能找到指定对象信息");
+                {
+                    return JsonHelper.Instance.Serialize(new TableData
+                    {
+                        msg ="未找到指定的节点",
+                        code = 500,
+                    });
+                }
                 cascadeId = org.CascadeId;
             }
 
diff --git a/OpenAuth.Repository/BaseRepository.cs b/OpenAuth.Repository/BaseRepository.cs
index e65a493d..ba2ee536 100644
--- a/OpenAuth.Repository/BaseRepository.cs
+++ b/OpenAuth.Repository/BaseRepository.cs
@@ -145,7 +145,7 @@ namespace OpenAuth.Repository
 
         private IQueryable<T> Filter(Expression<Func<T, bool>> exp)
         {
-            var dbSet = Context.Set<T>().AsQueryable();
+            var dbSet = Context.Set<T>().AsNoTracking().AsQueryable();
             if (exp != null)
                 dbSet = dbSet.Where(exp);
             return dbSet;
diff --git a/OpenAuth.Repository/OpenAuthDBContext.cs b/OpenAuth.Repository/OpenAuthDBContext.cs
index ea89daca..b8966a61 100644
--- a/OpenAuth.Repository/OpenAuthDBContext.cs
+++ b/OpenAuth.Repository/OpenAuthDBContext.cs
@@ -8,6 +8,7 @@
 //------------------------------------------------------------------------------
 
 using System.Data.Entity;
+using System.Data.Entity.Infrastructure;
 using OpenAuth.Repository.Domain;
 using OpenAuth.Repository.Mapping;
 
@@ -25,6 +26,11 @@ namespace OpenAuth.Repository
         {
             // 关闭语义可空判断
             Configuration.UseDatabaseNullSemantics = true;
+
+            //与变量的值为null比较
+            //ef判断为null的时候，不能用变量比较：https://stackoverflow.com/questions/682429/how-can-i-query-for-null-values-in-entity-framework?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa
+            (this as IObjectContextAdapter).ObjectContext.ContextOptions.UseCSharpNullComparisonBehavior = true;
+            Database.Log = s => System.Diagnostics.Debug.WriteLine(s);
         }
 
         public OpenAuthDBContext(string nameOrConnectionString)
diff --git a/OpenAuth.Repository/UnitWork.cs b/OpenAuth.Repository/UnitWork.cs
index 1c48bef6..581841df 100644
--- a/OpenAuth.Repository/UnitWork.cs
+++ b/OpenAuth.Repository/UnitWork.cs
@@ -85,9 +85,14 @@ namespace OpenAuth.Repository
         public void Update<T>(T entity) where T:class
         {
             var entry = this.Context.Entry(entity);
-            //todo:如果状态没有任何更改，会报错
             entry.State = EntityState.Modified;
 
+            //如果数据没有发生变化
+            if (!this.Context.ChangeTracker.HasChanges())
+            {
+                entry.State = EntityState.Unchanged;
+            }
+
         }
 
         public void Delete<T>(T entity) where T:class
@@ -136,7 +141,7 @@ namespace OpenAuth.Repository
 
         private IQueryable<T> Filter<T>(Expression<Func<T, bool>> exp) where T : class
         {
-            var dbSet = Context.Set<T>().AsQueryable();
+            var dbSet = Context.Set<T>().AsNoTracking().AsQueryable();
             if (exp != null)
                 dbSet = dbSet.Where(exp);
             return dbSet;
diff --git a/OpenAuth.UnitTest/TestOrg.cs b/OpenAuth.UnitTest/TestOrg.cs
index e1f6e7f0..d9ac8cf8 100644
--- a/OpenAuth.UnitTest/TestOrg.cs
+++ b/OpenAuth.UnitTest/TestOrg.cs
@@ -23,7 +23,7 @@ namespace OpenAuth.UnitTest
         {
             try
             {
-                for (int i = 0; i < 2; i++)
+                for (int i = 0; i < 5; i++)
                 {
                     var random = new Random();
                     int val = random.Next();
@@ -43,5 +43,17 @@ namespace OpenAuth.UnitTest
                 Console.WriteLine(e.Message);
             }
         }
+
+
+        [TestMethod]
+        public void update()
+        {
+            _app.Update(new Org
+            {
+                Id = "4bcdd85d-662f-42e4-94dc-19e3e98ef4dc",
+                Name = "测试",
+                ParentId = "57239263-0176-4ef9-a4b5-3491a04e2c6a"
+            });
+        }
     }
 }