如何在存储过程中判断ID=某个值的数据是否存在，在.net程序中获取存储过程返回的值

存储过程
create proc UP_CheckUser
(
@col_id int,
@Result int output
)
as
begin
begin try
select * from 表名 where col_id=@col_id
if(@@rowcount=0)
begin
select @Result=1
end
else
begin
select @Result=0
end
end try
begin catch
select @Result=0
end catch
end
go

后台文件：
SqlParameter[] sp = new SqlParameter[2];
sp[0] = new SqlParameter("@col_id", col_id);
sp[1] = new SqlParameter("@Result", SqlDbType.Int);
sp[1].Direction = ParameterDirection.Output;
cmd.ExecuteNonQuery(CommandType.StoredProcedure, "CheckUser", sp);
int nResult = Convert.ToInt32(sp[1].Value);

if (nResult == 0)
{
return 0;
}
else
{