asp.net mssql multiple condition query and paging stored procedure

CREATE PROCEDURE [Dbo].searchbykey

@iskeyword varchar (100),
@iskf varchar (100),
@isdy varchar (100),
@iszj varchar (100),
@lr_begin varchar (100),
@lr_end varchar (100),
@iszt varchar (50),
@islx varchar (100),
@isly varchar (100),
@pagesize int,--page size
@pageindex INT--page number
As
Declare

@sqlsel varchar (1000),
@strsql varchar (1000)

Set @sqlsel =+ ' select * from Sickinfo where 1=1 '

if (@iskeyword!= ')
Set @sqlsel = IsNull (@sqlsel, ') + ' and askedinfo like ' + '% ' + @iskeyword + '% '

                if (@iskf!= ')
                  Set   @sqlsel =isnull (@sqlsel, ') + ' and kefu= ' + @iskf + ' "'
                 if (@isdy!= ')
                   set  @sqlsel =isnull (@sqlsel, ') + ' and admit= ' + @isdy + '
                if (@iszj!= ') )
                  Set   @sqlsel =isnull (@sqlsel, ') + ' and zhuanjia= ' + @iszj + ' "'
                 if (@lr_begin!= ' and @lr_end!= ')

Set @sqlsel = @sqlsel + ' and addtime between ' "+convert (char), CONVERT (DateTime, @lr_begin)," "+convert" ( char (+), CONVERT (DateTime, @lr_end), 21) + ' "

if (@iszt!= ')
Set @sqlsel =isnull (@sqlsel, ') + ' and state = ' + @iszt + ' "'
if (@islx!= ')
Set @sqlsel =isnull (@sqlsel, ') + ' and istype= ' + @islx + ' "'

if (@isly!= ')
Set @sqlsel =isnull (@sqlsel, ') + ' and Infofrom = ' + @isly + ' "'

--Arranged in order
--set @strsql = ' select Top ' +str (@pagesize) + ' * FROM (' + @sqlsel + ') as T1 where id> (the Select ISNULL (max (ID), 0) from (sele CT top ' + str ((@pageindex-1) * @pagesize) + ' ID to (' + @sqlsel + ') as T2 order by ID as T)
--Flashback arrangement

if (@pageindex =1)
Begin
Set @strsql = ' Select Top ' +str (@pagesize) + ' * FROM (' + @sqlsel + ') as TT ORDER BY id DESC '
--set @strsql = ' select Top ' +str (@pagesize) + ' * out #temp2 ORDER BY id DESC '

End
Else
Begin
Set @strsql = ' Select Top ' +str (@pagesize) + ' * FROM (' + @sqlsel + ') as T1 where id< (select IsNull (min (id), 0) from (select Top ' +str ((@pageindex-1) * @pagesize) + ' ID from (' + @sqlsel + ') as T2 ORDER by id desc) as T "ORDER by id DESC '
End
EXEC (@strsql)
--exec @strsql
Go

Functions that call this stored procedure

Public DataSet Searchbykey (String strSQL, String Iskeyword, String iskf, String isdy, String Iszj, String Lr_begin, String Lr_end, String Iszt, String islx, String isly,int pagesize,int pageindex)
{
Checkconnection ();
DataSet ds1 = new DataSet ();
Try
{
cmd = new SqlCommand (strSQL, con);
Cmd.commandtype = CommandType.StoredProcedure;
Sqlparameter[] para = {new SqlParameter ("@iskeyword", SqlDbType.VarChar),
New SqlParameter ("@iskf", SqlDbType.VarChar),
New SqlParameter ("@isdy", SqlDbType.VarChar),
New SqlParameter ("@iszj", SqlDbType.VarChar),
New SqlParameter ("@lr_begin", SqlDbType.VarChar),
New SqlParameter ("@lr_end", SqlDbType.VarChar),
New SqlParameter ("@iszt", SqlDbType.VarChar),
New SqlParameter ("@islx", SqlDbType.VarChar),
New SqlParameter ("@isly", SqlDbType.VarChar),
New SqlParameter ("@pagesize", SqlDbType.VarChar),
New SqlParameter ("@pageindex", SqlDbType.VarChar)};
Para[0].value = Iskeyword;
Para[1].value = ISKF;
Para[2].value = Isdy;
Para[3].value = ISZJ;
Para[4].value = Lr_begin;
Para[5].value = Lr_end;
Para[6].value = Iszt;
Para[7].value = ISLX;
Para[8].value = isly;
Para[9].value = pagesize;
Para[10].value = pageindex;
Cmd.parameters.addrange (para);
SqlDataAdapter dap = new SqlDataAdapter ();
Dap.selectcommand = cmd;
Dap.fill (DS1, "sickinfo");
}
catch (Exception e)
{
E.message.tostring ();
}
Finally
{
Con.close ();
}
return DS1;
}