custom paging with searching

//Pass FirstRec ,CurrentPage ,PageSize ,LastRec,OrderBy,OrderByType   parameter through .Net

declare @total int  //count total row
Declare @FirstRec int
 declare @CurrentPage int
declare  @PageSize int
Declare @LastRec int

Set @FirstRec = (@CurrentPage - 1) * @PageSize
Set @LastRec = (@CurrentPage * @PageSize + 1)


IF(@OrderBy = '' or @OrderBy = 'Default')  
BEGIN  
 set @OrderBy = 'mpv.VisitDate '  
 set @OrderByType='desc'
 END

exec ( '
SELECT * FROM
(


SELECT  ROW_NUMBER() OVER (ORDER BY ' +  @OrderBy + ' ' + @OrderByType + ') AS RowNum,
               mp.PatientID,mp.FirstName+'' '' +mp.LastName + case when mp.MobileNumber <>''''  then  ''/ '' + mp.mobilenumber else ''''  END Name , convert(varchar(10),mpv.VisitDate,103)VisitDate,mpv.PatientVisitID,(select count(*) from     MDTM_Patient mp left JOIN MDTM_Patient_VisitDetail mpv on mp.PatientID=mpv.PatientID
                where  mp.IsDeleted=0 and mp.CreatedBy='+@LoginUserId +')as totalpatient,mc.ConsultationType,convert(varchar(10),mc.SentForReviewOn,103)SentForReviewOn,mu.FirstName +'' ''+ mu.LastName as Referto,mc.CaseStatus
             
            FROM MDTM_Patient mp left JOIN MDTM_Patient_VisitDetail mpv on mp.PatientID=mpv.PatientID left join MDTM_Patient_Consultation mc  on mpv.PatientID=mc.PatientID and mc.isdeleted=0 left join MDTM_Users mu on mc.ReferredToDoctor=mu.UserID and mu.IsDeleted=0
                where  mp.IsDeleted=0 and mp.CreatedBy='+@LoginUserId +'   and
(
             mp.FirstName like  '''+ @search+ '%'' or mp.LastName like  '''+ @search+ '%'' or
             mp.FirstName+'' ''+mp.LastName LIKE '''+ @search+ '%'' OR
             mu.FirstName like  '''+ @search+ '%'' or mu.LastName like  '''+ @search+ '%'' OR
             mu.FirstName+'' ''+mu.LastName LIKE '''+ @search+ '%'' OR
             mc.CaseStatus LIKE  '''+ @search+ '%'' OR
             CONVERT(varchar,mpv.VisitDate,105)= '''+ @search+ ''' OR
             CONVERT(varchar,mc.SentForReviewOn,105)= '''+ @search+ '''
             )
) records
where records.RowNum>' + @FirstRec  + ' and records.RowNum<  '+@LastRec )