错误：“未将对象引用设置到对象的实例 ” 存储过程带参数输出

[opbsm]

public DataView SelectUser(int pageIndex,int pageSize,out int countNum)
{
conn=DB.DBConnection();
conn.Open();
SqlDataAdapter sdr=new SqlDataAdapter();
sdr.SelectCommand=new SqlCommand("page_user",conn);
sdr.SelectCommand.CommandType=CommandType.StoredProcedure;


sdr.SelectCommand.Parameters.Add("@pageIndex",SqlDbType.Int,4);
sdr.SelectCommand.Parameters.Add("@pageSize",SqlDbType.Int,4);
sdr.SelectCommand.Parameters.Add("@intUserCount",SqlDbType.Int,4);

sdr.SelectCommand.Parameters["@pageIndex"].Value=pageIndex;
sdr.SelectCommand.Parameters["@pageSize"].Value=pageSize;
sdr.SelectCommand.Parameters["@intUserCount"].Direction=ParameterDirection.Output;

countNum=Int32.Parse(sdr.SelectCommand.Parameters["@intUserCount"].Value.ToString());//这里报错

conn.Close();
DataSet ds=new DataSet();
sdr.Fill(ds,"userlist");
return ds.Tables["userlist"].DefaultView;



未将对象引用设置到对象的实例。
----------

一个分页的存储过程，求首尾ID的
CREATE PROCEDURE page_user

@pageIndex int ,/*当前页数*/
@pagesize int,/*每页多少页*/
@intUserCount int output/*求总数*/
as
set nocount on

declare @BeginId int
declare @PageNum int
declare @lastid int

select @intUserCount=count(*) from clubuser

set @PageNum=@pagesize*(@pageIndex-1)+1
set rowcount @PageNum
select @BeginId=id from clubuser order by id

set @PageNum=@pagesize*@pageIndex
set rowcount @PageNum
select @lastid=id from clubuser order by id

set rowcount 0
set nocount off
select * from clubuser where id between @BeginId and @lastid order by id desc

GO

[brightheroes]

countNum=Int32.Parse(sdr.SelectCommand.Parameters["@intUserCount"].Value.ToString());//这里报错

conn.Close();
DataSet ds=new DataSet();
sdr.Fill(ds,"userlist");

--->



conn.Close();
DataSet ds=new DataSet();
sdr.Fill(ds,"userlist");

countNum=Int32.Parse(sdr.SelectCommand.Parameters["@intUserCount"].Value.ToString());//换换顺序

[opbsm]

谢谢！！高顶了，马上给分