<%@ Control Language="C#" AutoEventWireup="true" CodeFile="GridViewNavigator.ascx.cs"
    Inherits="Controls_GridViewNavigator" %>
<link href="../Css/ToolBar.css" type="text/css" rel="stylesheet" />
<div id="tblNoData" runat="server" style="border-top:solid 1px #EEE;border-bottom:solid 1px #EEE; padding: 10px 0px;
    background-color: #f9f9f9; text-align: center;">
    <asp:Label ID="lblNoData" runat="server" Text="當前資料庫中沒有符合條件的資料。" ForeColor="#FF7E42"></asp:Label>
</div>
<div id="tblPage" runat="server" style="text-align: right; padding-right: 10px;">
    <table width="100%">
        <tr>
            <td style="width: 50%" align=left>
                <asp:Label ID="lblItemNumber" runat="server" Enabled="False">總條目數</asp:Label>:
                <asp:Label ID="lblRecordCount" ForeColor="Red" runat="server" Enabled="False"></asp:Label>&nbsp;
                <asp:Label ID="lblPageItemNumber" runat="server" Enabled="False">每頁條目數</asp:Label>:
                <asp:Label ID="lblPageSize" ForeColor="Red" runat="server" Enabled="False"></asp:Label>&nbsp;
            </td>
            <td style="width: 50%" align=right>
               <asp:Label ID="lblCurrentPage" runat="server" Enabled="False">頁碼</asp:Label>:
                <asp:Label ID="lblPageIndex" ForeColor="Red" runat="server" Enabled="False"></asp:Label>
                <asp:Label ID="lblSplit" runat="server" Text="Label" Enabled="false">/</asp:Label>
                <asp:Label ID="lblPageCount" ForeColor="Red" runat="server" Enabled="False"></asp:Label>&nbsp;
               
                <asp:LinkButton ID="lnkFirst" runat="server" CausesValidation="False" CommandName="First"
                    Enabled="False">首頁</asp:LinkButton>&nbsp;
                <asp:LinkButton ID="lnkPrevious" runat="server" CausesValidation="False" CommandName="Previous"
                    Enabled="False">上一頁</asp:LinkButton>&nbsp;
                <asp:LinkButton ID="lnkNext" runat="server" CausesValidation="False" CommandName="Next"
                    Enabled="False">下一頁</asp:LinkButton>&nbsp;
                <asp:LinkButton ID="lnkLast" runat="server" CausesValidation="False" CommandName="Last"
                    Enabled="False">尾頁</asp:LinkButton>&nbsp;
                <asp:TextBox ID="txtPage" runat="server" CssClass="txtPage" Width="30px" Wrap="False"
                    Enabled="False">1</asp:TextBox>&nbsp;
                <asp:Button ID="btnGo" runat="server" CssClass="btnGo" Enabled="False"></asp:Button>
            </td>
        </tr>
    </table>

  
   
   
</div>

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Threading;

public partial class Controls_GridViewNavigator : System.Web.UI.UserControl
{
    private string _gridViewId = "";
  
    private int _pageIndex = 1;
    private int _pageSize = 25;
    private string _keyField = "";
    //private string _sortField = "";
    //private SortType _sortType = SortType.ASC;

    private DataTable _dataSource;

    public enum SortType
    {
        ASC,DESC
    }

    protected void Page_Load(object sender, System.EventArgs e)
    {
        if (!this.IsPostBack)
        {
            this.Unload += new EventHandler(Controls_GridViewPage_Unload);
            txtPage.Attributes.Add("onkeypress", "if(event.keyCode == 13){document.all." + btnGo.ClientID + ".click();event.returnValue=false;}");
            txtPage.Attributes.Add("onmouseover", "if(!document.all." + txtPage.ClientID + ".style.disabled){document.all." +
                txtPage.ClientID + ".focus();document.all." + txtPage.ClientID + ".select();}");
        }
    }

    void Controls_GridViewPage_Unload(object sender, EventArgs e)
    {
        if (Session["GridViewDataSource"] != null)
        {
            Session["GridViewDataSource"] = null;
        }
    }

    #region Properties

    /// <summary>
    /// 顯示資料表的DataGrid名稱
    /// </summary>
    public string GridViewId
    {
        get
        {
            return _gridViewId;
        }
        set
        {
            this._gridViewId = value;
        }
    }

    /// <summary>
    /// 取得用於確定DataGrid每一行的字段名稱，如:RoleID
    /// </summary>
    public string KeyField
    {
        get
        {
            return _keyField;
        }
        set
        {
            _keyField = value;
        }
    }

    /// <summary>
    /// 排序字段
    /// </summary>
    //public string SortField
    //{
    //    get
    //    {
    //        return _sortField;
    //    }
    //    set
    //    {
    //        _sortField = value;
    //    }
    //}

    /// <summary>
    /// 排序方式
    /// </summary>
    //public SortType SortDirection
    //{
    //    get
    //    {
    //        return _sortType;
    //    }
    //    set
    //    {
    //        _sortType = value;
    //    }
    //}

    /// <summary>
    /// 設定或取得當前頁碼
    /// </summary>
    public int PageIndex
    {
        get
        {
            //return _pageIndex;
            return (ViewState["PageIndex"] == null) ? _pageIndex : int.Parse(this.ViewState["PageIndex"].ToString());
        }
        set
        {
            _pageIndex = value;
            if (this.ViewState["PageIndex"] == null)
            {
                this.ViewState.Add("PageIndex", value);
            }
            else
            {
                this.ViewState["PageIndex"] = value;
            }
        }
    }

    ///<summary>
    ///設置pageSize，每頁顯示的紀錄條數
    ///</summary>
    public int PageSize
    {
        get
        {
            return _pageSize;
        }
        set
        {
            _pageSize = value;
        }
    }

    /// <summary>
    /// 用于綁定數據的Table
    /// </summary>
    public DataTable DataSource
    {
        get
        {
            if (Session["GridViewDataSource"] != null)
            {
                this._dataSource = Session["GridViewDataSource"] as System.Data.DataTable;
            }
            return this._dataSource;
        }
        set
        {
            this._dataSource = value;
            if (Session["GridViewDataSource"] == null)
            {
                Session.Add("GridViewDataSource", this._dataSource);
            }
            else
            {
                Session["GridViewDataSource"] = this._dataSource;
            }
            Navigate();
        }
    }

    #endregion

    /// <summary>
    /// 導向到某一頁面
    /// </summary>
    /// <param name="pageIndex">頁碼</param>
    public void Navigate(int targetPageIndex)
    {
        // 取得總頁數
        int pageCount=GetPageCount();

        if (targetPageIndex < 1)
        {
            PageIndex = 1;
        }
        if (targetPageIndex > pageCount)
        {
            PageIndex = pageCount;
        }
        else
        {
            PageIndex = targetPageIndex;
        }

        ShowPage();
    }

    /// <summary>
    /// 初始化資料，並顯示第一頁
    /// </summary>
    private void Navigate()
    {
        PageIndex = 1;
        ShowPage();
    }

    /// <summary>
    /// 綁定數據
    /// </summary>
    private void ShowPage()
    {
        try
        {
            BindGridViewData();
            DisplayPagingStatus();
            EnablePagingControls();
        }
        catch (Exception ex)
        {
            string msg = ex.Message;
            throw ex;
        }
    }

    private void BindGridViewData()
    {
        try
        {
            System.Web.UI.Control ctrl = this.Parent;
            GridView GridViewControl = (GridView)ctrl.FindControl(_gridViewId);
            if (this._pageSize > 0)
            {
                GridViewControl.PageSize = this._pageSize;
            }

            GridViewControl.DataSource = this.DataSource;
            if (!string.IsNullOrEmpty(this._keyField))
            {
                GridViewControl.DataKeyNames = new string[] { _keyField };
            }
            GridViewControl.PageIndex = this.PageIndex - 1;
            GridViewControl.DataBind();

            if (DataSource.Rows.Count <= 0)
            {
                tblNoData.Visible = true;
                tblPage.Visible = false;
            }
            else
            {
                tblNoData.Visible = false;
                tblPage.Visible = true;
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

    private void DisplayPagingStatus()
    {
        int pageCount = this.GetPageCount();
        int recordCount = this.GetRecordCount();

        lblPageIndex.Text = PageIndex.ToString();
        lblPageCount.Text = pageCount.ToString();
        lblRecordCount.Text = recordCount.ToString();
        lblPageSize.Text = _pageSize.ToString();
        txtPage.Text = PageIndex.ToString();
    }

 
    /// <summary>
    /// 設置翻頁按鈕的狀態
    /// </summary>
    public void EnablePagingControls()
    {
        int pageCount = this.GetPageCount();

        if (pageCount == 0)
        {
            lblCurrentPage.Enabled = false;
            lblPageIndex.Enabled = false;
            lblSplit.Enabled = false;
            lblPageCount.Enabled = false;
            lblItemNumber.Enabled = false;
            lblRecordCount.Enabled = false;
            lblPageItemNumber.Enabled = false;
            lblPageSize.Enabled = false;
        }
        else
        {
            lblCurrentPage.Enabled = true;
            lblPageIndex.Enabled = true;
            lblSplit.Enabled = true;
            lblPageCount.Enabled = true;
            lblItemNumber.Enabled = true;
            lblRecordCount.Enabled = true;
            lblPageItemNumber.Enabled = true;
            lblPageSize.Enabled = true;

        if (pageCount <= 1)
        {   //小於等於一頁
            this.lnkFirst.Enabled = false;
            this.lnkPrevious.Enabled = false;
            this.lnkNext.Enabled = false;
            this.lnkLast.Enabled = false;
            this.txtPage.Enabled = false;
            this.btnGo.Enabled = false;
        }
        else
        {
            //有多頁
            if (PageIndex == 1)
            {
                //當前為第一頁
                this.lnkFirst.Enabled = false;
                this.lnkPrevious.Enabled = false;
                this.lnkNext.Enabled = true;
                this.lnkLast.Enabled = true;
            }
            else if (PageIndex == pageCount)
            {
                //當前為最後頁
                this.lnkFirst.Enabled = true;
                this.lnkPrevious.Enabled = true;
                this.lnkNext.Enabled = false;
                this.lnkLast.Enabled = false;
            }
            else
            {  //中間頁
                this.lnkFirst.Enabled = true;
                this.lnkPrevious.Enabled = true;
                this.lnkNext.Enabled = true;
                this.lnkLast.Enabled = true;
            }
            this.txtPage.Enabled = true;
            this.btnGo.Enabled = true;
        }
        }
    }

    /// <summary>
    /// 取得總頁數
    /// </summary>
    private int GetPageCount()
    {
        int recordCount = GetRecordCount();
        int pageCount = (recordCount % _pageSize == 0) ? Convert.ToInt32(recordCount / _pageSize) : Convert.ToInt32(recordCount / _pageSize) + 1;
        return pageCount;
    }

    /// <summary>
    /// 取得總條目數
    /// </summary>
    /// <returns></returns>
    private int GetRecordCount()
    {
        return this.DataSource.Rows.Count;
    }

    #region EventHandler

    /// <summary>
    /// 頁碼變換:上頁、下頁、前頁、后頁
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void OnNavigate(object sender, System.Web.UI.WebControls.CommandEventArgs e)
    {
        LinkButton lnkPage = (LinkButton)sender;
    
        this.PageIndex=CalculateTargetPageIndex(lnkPage.CommandName);
        ShowPage();
    }

    /// <summary>
    /// 直接跳轉到某一頁
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void btnGo_Click(object sender, System.EventArgs e)
    {
        try
        {
            int inputPageIndex = 0;
            int.TryParse(txtPage.Text.Trim(), out inputPageIndex);
            this.PageIndex = CalculateTargetPageIndex(inputPageIndex);
            ShowPage();
        }
        catch (Exception ex)
        {
            string msg = ex.Message;
            throw ex;
        }
    }

    private int CalculateTargetPageIndex(string commandName)
    {
        int targetPageIndex = 0;
        int pageCount = this.GetPageCount();

        switch (commandName)
        {
            case "First": // 第1頁
                {
                    targetPageIndex = 1;
                }
                break;

            case "Previous": // 前頁
                if (PageIndex > 1)
                {
                    targetPageIndex = PageIndex - 1;
                }
                break;
            case "Next": // 后頁
                if (PageIndex < pageCount)
                {
                    targetPageIndex = PageIndex + 1;
                }
                break;
            case "Last": // 尾頁
                {
                    targetPageIndex = pageCount;
                }
                break;
        }

        return targetPageIndex;

    }

    private int CalculateTargetPageIndex(int intputPageIndex)
    {
        int targetPageIndex = 0;
        int pageCount = this.GetPageCount();

        if (intputPageIndex > pageCount)
        {
            targetPageIndex = pageCount;
        }
        else if (intputPageIndex <= 1)
        {
            targetPageIndex = 1;
        }
        else
        {
            targetPageIndex = intputPageIndex;
        }

        return targetPageIndex;
    }

    #endregion

    #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.lnkFirst.Command += new System.Web.UI.WebControls.CommandEventHandler(OnNavigate);
        this.lnkPrevious.Command += new System.Web.UI.WebControls.CommandEventHandler(OnNavigate);
        this.lnkNext.Command += new System.Web.UI.WebControls.CommandEventHandler(OnNavigate);
        this.lnkLast.Command += new System.Web.UI.WebControls.CommandEventHandler(OnNavigate);
        this.btnGo.Click += new System.EventHandler(this.btnGo_Click);
        this.Load += new System.EventHandler(this.Page_Load);

    }

    #endregion
}