Golang modifying the value of a structure slice

//  Complete product information ,  Product name , product price 
	var mallGoods []mall.MallGoods
	err = global.GVA_DB.Model(&mall.MallGoods{}).Where("id in ?", Ids).Find(&mallGoods).Error

	for _, val := range mallGoods {
		for k, valuein := range dataRes {
			if valuein.Pid == int(val.ID) {
				dataRes[k].Title = val.Title
				dataRes[k].Price = *val.Price

				//  Error code 
				//valuein.Title = val.Title
				//valuein.Price = *val.Price
				//fmt.Println(valuein.Price)
			}
		}
	}

Step on the pit , use Structure of the key To modify the value , Use value You can't change the value