stem.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;

public partial class GridViewPaging : System.Web.UI.Page
{
//每页显示的最多记录的条数
private int pageSize = 10;
//当前页号
private int currentPageNumber;
//显示数据的总条数
private static int rowCount;
//总页数
private static int pageCount;

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
SqlConnection cn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString);

SqlCommand cmd = new SqlCommand("GetProductsCount", cn);
cmd.CommandType = CommandType.StoredProcedure;
cn.Open();
rowCount = (int)cmd.ExecuteScalar();
cn.Close();
pageCount = (rowCount - 1) / pageSize + 1;
currentPageNumber = 1;
ViewState["currentPageNumber"] = currentPageNumber;
lbtnPrevious.Enabled = false;
lbtnFirst.Enabled = false;

for (int i = 1; i <= pageCount; i++)
{
dropPage.Items.Add(new ListItem(i.ToString(), i.ToString()));
}
dropPage.SelectedValue = dropPage.Items.FindByValue(currentPageNumber.ToString()).Value;
SqlDataSource1.Select(DataSourceSelectArguments.Empty);
}
}

protected void SqlDataSource1_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
{
SqlDataSource1.SelectParameters["PageNumber"].DefaultValue = currentPageNumber.ToString();
SqlDataSource1.SelectParameters["PageSize"].DefaultValue = pageSize.ToString();
}

protected void SqlDataSource1_Selected(object sender, SqlDataSourceStatusEventArgs e)
{
lblMessage.Text = "共找到" + rowCount + "条记录, 当前第" + currentPageNumber + "/" + pageCount + "页";
}

protected void lbtnPage_Command(object sender, CommandEventArgs e)
{
switch (e.CommandName)
{
case "First":
currentPageNumber = 1;
break;
case "Previous":
currentPageNumber = (int)ViewState["currentPageNumber"] - 1 > 1 ? (int)ViewState["currentPageNumber"] - 1 : 1;
break;
case "Next":
currentPageNumber = (int)ViewState["currentPageNumber"] + 1 < pageCount ? (int)ViewState["currentPageNumber"] + 1 : pageCount;
break;
case "Last":
currentPageNumber = pageCount;
break;
}
dropPage.SelectedValue = dropPage.Items.FindByValue(currentPageNumber.ToString()).Value;
ViewState["currentPageNumber"] = currentPageNumber;
SetButton(currentPageNumber);
SqlDataSource1.Select(DataSourceSelectArguments.Empty);
}

private void SetButton(int currentPageNumber)
{
lbtnFirst.Enabled = currentPageNumber != 1;
lbtnPrevious.Enabled = currentPageNumber != 1;
lbtnNext.Enabled = currentPageNumber != pageCount;
lbtnLast.Enabled = currentPageNumber != pageCount;
}

protected void dropPage_SelectedIndexChanged(object sender, EventArgs e)
{
currentPageNumber = int.Parse(dropPage.SelectedValue);
ViewState["currentPageNumber"] = currentPageNumber;
SetButton(cur