[WebApiUtils] Get object by primary key

WebApiUtils/BusinessManager/SqlServerManager.cs

             return Add(DboToDbStatic(obj));
         }
 
+        /// <summary>
+        /// Get an object by its primary key(s)
+        /// </summary>
+        /// <param name="pairs">The key names and values</param>
+        /// <returns>The object</returns>
+        public static OpResult<TDbObject> GetByPrimary(params KeyValuePair<string, object>[] pairs)
+        {
+            var param = Expression.Parameter(typeof(TDbObject), "x");
+            Expression totalExp = null;
+            foreach (var pair in pairs)
+            {
+                var equalExp = Expression.Equal(Expression.Property(param, pair.Key), Expression.Constant(pair.Value));
+                totalExp = totalExp == null ? equalExp : Expression.And(equalExp, totalExp);
+            }
+            var lambda = Expression.Lambda<Func<TDbObject, bool>>(totalExp, param);
+            return GetSingle(lambda);
+        }
+
         /// <summary>
         /// Get an object by its id
         /// </summary>
         /// <returns>The object</returns>
         public static OpResult<TDbObject> GetById(long id)
         {
-            var param = Expression.Parameter(typeof(TDbObject), "x");
-            var exp = Expression.Lambda<Func<TDbObject, bool>>(
-                Expression.Equal(
-                    Expression.Property(param, "id"),
-                    Expression.Constant(id)
-                ), param);
-            return GetSingle(exp);
+            return GetByPrimary(new KeyValuePair<string, object>("id", id));
         }
 
         /// <summary>