存入数据库的数据产生空格

char(20):存放20位，不够的将用空格补齐

nvarchar(2):最多存放20位

同时，向数据库跟新或者插入数据时，如果不想产生空格，最好设置字段varchar或者nvarchar类型：

        public bool Add(Model.Model_Companey model)        {            StringBuilder strSql = new StringBuilder();            strSql.Append("insert into Companey (");            strSql.Append("C_OraName,C_Town,C_Trding,C_Postcode,C_Phone)");            strSql.Append(" values(");                           strSql.Append("@C_OraName,@C_Town,@C_Trding,lrtrim(@C_Postcode),lrtrim(@C_Phone))");            SqlParameter[] parameters = {                                        new SqlParameter("@C_OraName",SqlDbType.NVarChar,50),                                        new SqlParameter("@C_Town",SqlDbType.NVarChar,50),                                        new SqlParameter("@C_Trding",SqlDbType.NVarChar,50),                                        new SqlParameter("@C_Postcode",SqlDbType.NVarChar,10),                                        new SqlParameter("@C_Phone",SqlDbType.NVarChar,20)};            parameters[0].Value = model.C_OraName;            parameters[1].Value = model.C_Town;            parameters[2].Value = model.C_Trding;            parameters[3].Value = model.C_Postcode;            parameters[4].Value = model.C_Phone;            int rows = Helper.SQLHelper.ExcuteSQL(strSql.ToString(), parameters);            if (rows > 0)            {                return true;            }            else            {                return false;            }        }