diff --git a/Src/Asp.NetCore2/SqlSugar/Abstract/ExecuteNavProvider/InsertNavProviderHelper.cs b/Src/Asp.NetCore2/SqlSugar/Abstract/ExecuteNavProvider/InsertNavProviderHelper.cs
index eb5fb207f..d8d038dfb 100644
--- a/Src/Asp.NetCore2/SqlSugar/Abstract/ExecuteNavProvider/InsertNavProviderHelper.cs
+++ b/Src/Asp.NetCore2/SqlSugar/Abstract/ExecuteNavProvider/InsertNavProviderHelper.cs
@@ -94,6 +94,10 @@ namespace SqlSugar
         private void InsertDatas<TChild>(List<TChild> children, EntityColumnInfo pkColumn, EntityColumnInfo NavColumn=null) where TChild : class, new()
         {
             children = children.Distinct().ToList();
+            if (pkColumn == null) 
+            {
+                Check.ExceptionEasy($"{typeof(TChild).Name} need primary key ", $"{typeof(TChild).Name}需要主键");
+            }
             var x = this._Context.Storageable(children).WhereColumns(new string[] { pkColumn.PropertyName }).ToStorage();
             var insertData = children = x.InsertList.Select(it => it.Item).ToList();
             var IsNoExistsNoInsert = _navOptions != null && _navOptions.OneToManyIfExistsNoInsert == true;
diff --git a/Src/Asp.NetCore2/SqlSugar/Utilities/UtilMethods.cs b/Src/Asp.NetCore2/SqlSugar/Utilities/UtilMethods.cs
index a642d3d7c..bd5f60415 100644
--- a/Src/Asp.NetCore2/SqlSugar/Utilities/UtilMethods.cs
+++ b/Src/Asp.NetCore2/SqlSugar/Utilities/UtilMethods.cs
@@ -370,6 +370,7 @@ namespace SqlSugar
                 else
                     return Enum.ToObject(type, value);
             }
+            if (value is string && type == typeof(Guid?)) return value.IsNullOrEmpty() ? null : (Guid?)new Guid(value as string);
             if (!type.IsInterface && type.IsGenericType)
             {
                 Type innerType = type.GetGenericArguments()[0];