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;
            }
        }