public class DataNavigator
{
private int TotalPages;
private int CurrentPage;
private int PagesOnPage;
private int RecordCount;
public int totalPages
{
get
{
return TotalPages;
}
set
{
TotalPages = totalPages;
}
}
public int currentPage
{
get
{
return CurrentPage;
}
set
{
CurrentPage = currentPage;
}
}
public int pagesOnPage
{
get
{
return PagesOnPage;
}
set
{
PagesOnPage = pagesOnPage;
}
}
public DataNavigator()
{
}
public void Init(int iNumPage, int iRecCount,int iPagesOnPage, int iPageSize)
{
int iFirstRec;
PagesOnPage = iPagesOnPage;
RecordCount = iRecCount;
if (iNumPage == 1)
{
iFirstRec = 1;
}
else
{
iFirstRec = iNumPage*iPageSize;
}
if ((iRecCount % iPageSize) != 0 )
{
TotalPages = iRecCount / iPageSize + 1;
}
else
{
TotalPages = iRecCount / iPageSize;
}
if (CurrentPage < 1)
{
CurrentPage = 1;
}
if (CurrentPage > TotalPages)
{
CurrentPage = TotalPages;
}
if ((iFirstRec % iPageSize) != 0)
{
CurrentPage = iFirstRec / iPageSize +1;
}
else
{
CurrentPage = iFirstRec / iPageSize;
}
}
public int RenderEventPageBar(ref string XML)
{
int i, j, k;
if (TotalPages < 2)
{
XML = XML + "<Pages></Pages>";
return 0;
}
i = ((CurrentPage - 1) / PagesOnPage) * PagesOnPage + 1;
j = i + PagesOnPage - 1;
if (j > TotalPages)
{
j = TotalPages;
}
XML = XML + "<Pages>";
if (CurrentPage > 1)
{
XML = XML + "<FirstPage Page='1'/>";
}
if (i > PagesOnPage)
{
XML = XML + "<PrevNPages Page='" + Convert.ToString(i - PagesOnPage) + "'/>";
}
if (CurrentPage > 1)
{
XML = XML + "<PrevPage Page='" + Convert.ToString(CurrentPage - 1) + "'/>";
}
for (k = i; k<= j; k++)
{
if (k == CurrentPage)
{
XML = XML + "<CurPage Page='" + k.ToString() + "'/>";
}
else
{
XML = XML + "<ToPage Page='" + k.ToString() + "'/>";
}
}
if (CurrentPage < TotalPages)
{
XML = XML + "<NextPage Page='" + Convert.ToString(CurrentPage + 1) + "'/>";
}
if (j < TotalPages)
{
XML = XML + "<NextNPages Page='" + Convert.ToString(j + 1) + "'/>";
}
if (CurrentPage < TotalPages)
{
XML = XML + "<LastPage Page='" + TotalPages.ToString() + "'/>";
}
XML = XML + "</Pages>";
return 0;
}
public static string CountPage()
{
HttpContext hc = HttpContext.Current;
string page = "1";
try
{
if ( hc.Request.QueryString["prevpage"] != null)
{
page = hc.Request.QueryString["prevpage"];
}
else
{
if (hc.Request.QueryString["nextpage"] != null)
{
page = hc.Request.QueryString["nextpage"];
}
else
{
if (hc.Request.QueryString["gotopage"] == null)
{
page = "1";
}
else
{
page = hc.Request.QueryString["gotopage"];
}
}
}
}
catch
{
page = "1";
}
return page;
}
}

Comments:

RenderNavigationBar(...) function returns XML description of the navigation bar, which should be translated to a HTML string with provided XSLT;
CountPage(...) is a helper function which determines which page user has requested basing on Request.QueryString collection

public class FTPactivity : System.Web.UI.Page
{
public int PagesOnPage = 20;
public int PageSize = 25;
public int RecCount;
private void Page_Load(object sender, System.EventArgs e)
{ if(!Page.IsPostBack)
{
string page = DataNavigator.CountPage();
DisplaySearchResults(Convert.ToInt32(page));
}
}
private void DisplaySearchResults(int page)
{
DataActivityGrid.DataSource = FTPReader.GetActivity((page-1)*PageSize,page*PageSize,SortExpression,out sqlCommand);
DataActivityGrid.DataBind();

if(DataActivityGrid.DataSource != null)
((SqlDataReader)DataActivityGrid.DataSource).Close();
RecCount = Convert.ToInt32(sqlCommand.Parameters["@record_count"].Value);

string xml = "";
DataNavigator dn = new DataNavigator();
if(page != PagesOnPage)
{
dn.Init(page,RecCount,PagesOnPage,PageSize);
}
else
{
dn.Init(page,PageSize*PagesOnPage,PagesOnPage,PageSize);
}

dn.RenderEventPageBar(ref xml);

XsltArgumentList xsltArgList = new XsltArgumentList();
xsltArgList.AddParam("RedirectPage","","ftpactivity.aspx");
aspPageNavigator.Text = DataTransform.TransformXmlString(xml,Server.MapPath("xsl/navbar.xslt"),xsltArgList);
}
}

Comments:

1) DataNavigator object should be initialized with following parameters:
current page number, total record count, number of pages displayed, number of records on one page
(see Init(...) method )
2) FTPReader.GetActivity(...) function is a DAL function which implements some business logic 3) and interacts with SQL stored procedures;
4) aspPageNavigator is an asp:Label control which actually displays this page navigation bar;
5) DataTransform is a class for XML/XSL transformation (refer to my article);
6) DataActivityGrid is a datagrid control which displays SQL data;