DataGrid中自定分页

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.OleDb;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace fenye
{
 /// <summary>
 /// DataGridPaging 的摘要描述。
 /// </summary>
 public class DataGridPaging : System.Web.UI.Page
 {
  protected System.Web.UI.WebControls.DataGrid MyDataGrid;
  protected System.Web.UI.WebControls.Label lblPageCount;
  protected System.Web.UI.WebControls.Label lblCurrentIndex;
  protected System.Web.UI.WebControls.LinkButton btnFirst;
  protected System.Web.UI.WebControls.LinkButton btnPrev;
  protected System.Web.UI.WebControls.LinkButton btnNext;
  protected System.Web.UI.WebControls.LinkButton btnLast;
  protected System.Web.UI.WebControls.TextBox TextBox1;
  protected System.Web.UI.WebControls.Button Button1;
  protected System.Web.UI.WebControls.Label lblRecords;
  private OleDbConnection cn = new OleDbConnection();
  private void Page_Load(object sender, System.EventArgs e)
  {
   // 在這裡放置使用者程式碼以初始化網頁
   btnFirst.Text = "最首頁";
   btnPrev.Text = "前一頁";
   btnNext.Text = "下一頁";
   btnLast.Text = "最後頁";
   Button1.Text = "跳轉";
   OpenDatabase();
   BindGrid();
   if(!Page.IsPostBack)
   {
    TextBox1.Text="1";
    btnFirst.Enabled=false;
    btnPrev.Enabled=false;
    if(MyDataGrid.PageCount<=1)
    {
     btnFirst.Enabled=false;
     btnPrev.Enabled=false;
     btnNext.Enabled=false;
     btnLast.Enabled=false;
    }
   }
  }
  private void OpenDatabase()
  {
   cn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Server.MapPath("sample.mdb");
   cn.Open();
  }
  private void ShowStats()
  {
   lblRecords.Text = "總共 " + ViewState["count"].ToString() + " 筆資料";
   lblCurrentIndex.Text = "第 " + (MyDataGrid.CurrentPageIndex + 1).ToString() + " 頁";
   lblPageCount.Text = "總共 " + MyDataGrid.PageCount.ToString() + " 頁";
  }
  public void PagerButtonClick(object sender, EventArgs e)
  {
   string arg = ((LinkButton)sender).CommandArgument.ToString();
   switch(arg)
   {
    case "first":
     MyDataGrid.CurrentPageIndex = 0;
     TextBox1.Text="1";
     btnFirst.Enabled=false;
     btnPrev.Enabled=false;
     btnNext.Enabled=true;
     btnLast.Enabled=true;
     break;
    case "next":
     if (MyDataGrid.CurrentPageIndex < (MyDataGrid.PageCount - 1))
     {
      MyDataGrid.CurrentPageIndex += 1;
      TextBox1.Text=System.Convert.ToString(System.Convert.ToInt32(TextBox1.Text) + 1);
      if(TextBox1.Text==System.Convert.ToString(MyDataGrid.PageCount))
      {
       btnFirst.Enabled=true;
       btnPrev.Enabled=true;
       btnNext.Enabled=false;
       btnLast.Enabled=false;
      }
      else
      {
       btnFirst.Enabled=true;
       btnPrev.Enabled=true;
       btnNext.Enabled=true;
       btnLast.Enabled=true;
      }
     }
     break;
    case "prev":
     if (MyDataGrid.CurrentPageIndex > 0)
     {
      MyDataGrid.CurrentPageIndex -= 1;
      TextBox1.Text=System.Convert.ToString(System.Convert.ToInt32(TextBox1.Text) - 1);
      if(TextBox1.Text=="1")
      {
       btnFirst.Enabled=false;
       btnPrev.Enabled=false;
       btnNext.Enabled=true;
       btnLast.Enabled=true;
      }
      else
      {
       btnFirst.Enabled=true;
       btnPrev.Enabled=true;
       btnNext.Enabled=true;
       btnLast.Enabled=true;
      }
     }
     break;
    case "last":
     MyDataGrid.CurrentPageIndex = (MyDataGrid.PageCount - 1);
     TextBox1.Text=MyDataGrid.PageCount.ToString().Trim();
     btnFirst.Enabled=true;
     btnPrev.Enabled=true;
     btnNext.Enabled=false;
     btnLast.Enabled=false;
     break;
   // default:
   //  MyDataGrid.CurrentPageIndex = System.Convert.ToInt32(arg);
   //  break;
   }
   BindGrid();
   ShowStats();
  }
  public void BindGrid()
  {
   OleDbConnection myConnection = cn;
   DataSet ds  = new DataSet();
   OleDbDataAdapter adapter  = new OleDbDataAdapter("Select Country,Province,City,School,Class from liandong", myConnection);
   adapter.Fill(ds, "liandong");
   MyDataGrid.DataSource = ds.Tables["liandong"].DefaultView;
   ViewState.Add("count",ds.Tables["liandong"].Rows.Count);
   MyDataGrid.DataBind();
   ShowStats();
  }
  public void MyDataGrid_Page(object sender, DataGridPageChangedEventArgs e)
  {
   int startIndex ;
   startIndex = MyDataGrid.CurrentPageIndex * MyDataGrid.PageSize;
   MyDataGrid.CurrentPageIndex = e.NewPageIndex;
   BindGrid();
   ShowStats();
  }

  #region Web Form 設計工具產生的程式碼
  override protected void OnInit(EventArgs e)
  {
   //
   // CODEGEN: 此為 ASP.NET Web Form 設計工具所需的呼叫。
   //
   InitializeComponent();
   base.OnInit(e);
  }
  
  /// <summary>
  /// 此為設計工具支援所必須的方法 - 請勿使用程式碼編輯器修改
  /// 這個方法的內容。
  /// </summary>
  private void InitializeComponent()
  {   
   this.Button1.Click += new System.EventHandler(this.Button1_Click);
   this.Load += new System.EventHandler(this.Page_Load);

  }
  #endregion

  private void Button1_Click(object sender, System.EventArgs e)
  {
   if(TextBox1.Text.Trim()=="")
   {
    MyDataGrid.CurrentPageIndex = 0;
    TextBox1.Text="1";
   }
   for(int i=0;i<TextBox1.Text.Length;i++)
   {
     if(TextBox1.Text[i].ToString().CompareTo("0")<0 ||TextBox1.Text[i].ToString().CompareTo("9")>0)
     {
      MyDataGrid.CurrentPageIndex = 0;
      TextBox1.Text="1";
     }
   }
   
   if(System.Convert.ToInt32(TextBox1.Text.Trim())<=0)
   {
    MyDataGrid.CurrentPageIndex = 0;
    TextBox1.Text="1";
   }
   else if(System.Convert.ToInt32(TextBox1.Text.Trim())>=MyDataGrid.PageCount)
   {
    MyDataGrid.CurrentPageIndex = (MyDataGrid.PageCount - 1);
    TextBox1.Text=MyDataGrid.PageCount.ToString().Trim();
   }
   else
    MyDataGrid.CurrentPageIndex = System.Convert.ToInt32(TextBox1.Text.Trim())-1;
   BindGrid();
   ShowStats();
   if(TextBox1.Text=="1")
   {
    btnFirst.Enabled=false;
    btnPrev.Enabled=false;
    btnNext.Enabled=true;
    btnLast.Enabled=true;
   }
   else if(TextBox1.Text==System.Convert.ToString(MyDataGrid.PageCount))
   {
    btnFirst.Enabled=true;
    btnPrev.Enabled=true;
    btnNext.Enabled=false;
    btnLast.Enabled=false;
   }
   else
   {
    btnFirst.Enabled=true;
    btnPrev.Enabled=true;
    btnNext.Enabled=true;
    btnLast.Enabled=true;
   }

  }

  
 }
}