- 增加 IUpdate.SetIf 方法；#309

FreeSql/Interface/Curd/IUpdate.cs

@@ -93,6 +93,15 @@ namespace FreeSql
         /// <returns></returns>
         IUpdate<T1> Set<TMember>(Expression<Func<T1, TMember>> column, TMember value);
         /// <summary>
+        /// 设置列的新值，Set(a => a.Name, "newvalue")
+        /// </summary>
+        /// <typeparam name="TMember"></typeparam>
+        /// <param name="condition">true 时生效</param>
+        /// <param name="column">lambda选择列</param>
+        /// <param name="value">新值</param>
+        /// <returns></returns>
+        IUpdate<T1> SetIf<TMember>(bool condition, Expression<Func<T1, TMember>> column, TMember value);
+        /// <summary>
         /// 设置列的的新值为基础上增加，格式：Set(a => a.Clicks + 1) 相当于 clicks=clicks+1
         /// <para></para>
         /// 指定更新，格式：Set(a => new T { Clicks = a.Clicks + 1, Time = DateTime.Now }) 相当于 set clicks=clicks+1,time='2019-06-19....'
@@ -102,6 +111,16 @@ namespace FreeSql
         /// <returns></returns>
         IUpdate<T1> Set<TMember>(Expression<Func<T1, TMember>> exp);
         /// <summary>
+        /// 设置列的的新值为基础上增加，格式：Set(a => a.Clicks + 1) 相当于 clicks=clicks+1
+        /// <para></para>
+        /// 指定更新，格式：Set(a => new T { Clicks = a.Clicks + 1, Time = DateTime.Now }) 相当于 set clicks=clicks+1,time='2019-06-19....'
+        /// </summary>
+        /// <typeparam name="TMember"></typeparam>
+        /// <param name="condition">true 时生效</param>
+        /// <param name="exp"></param>
+        /// <returns></returns>
+        IUpdate<T1> SetIf<TMember>(bool condition, Expression<Func<T1, TMember>> exp);
+        /// <summary>
         /// 设置值，自定义SQL语法，SetRaw("title = ?title", new { title = "newtitle" })
         /// </summary>
         /// <param name="sql">sql语法</param>

FreeSql/Internal/CommonProvider/UpdateProvider.cs

@@ -400,6 +400,7 @@ namespace FreeSql.Internal.CommonProvider
             SetPriv(cols.First().Column, value);
             return this;
         }
+        public IUpdate<T1> SetIf<TMember>(bool condition, Expression<Func<T1, TMember>> column, TMember value) => condition ? Set(column, value) : this;
         public IUpdate<T1> Set<TMember>(Expression<Func<T1, TMember>> exp)
         {
             var body = exp?.Body;
@@ -459,6 +460,7 @@ namespace FreeSql.Internal.CommonProvider
             _setIncr.Append(", ").Append(_commonUtils.QuoteSqlName(cols.First().Column.Attribute.Name)).Append(" = ").Append(expt);
             return this;
         }
+        public IUpdate<T1> SetIf<TMember>(bool condition, Expression<Func<T1, TMember>> exp) => condition ? Set(exp) : this;
         public IUpdate<T1> SetRaw(string sql, object parms = null)
         {
             if (string.IsNullOrEmpty(sql)) return this;