Interview Question: How to custom paging in datalist?

UI:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Custom Paging of DataList - Asp.NET(C#)</title>

<style>
.btnlink{color: #FFF;font-weight: bold;background-color: red;height: 40px;width: 40px;padding: 2px 10px 2px 10px;text-align: center;border: 2px solid yellow;}
.btnlP{color: #FFF;font-weight: bold;text-decoration: none;}
.shopage{color: #FFF;font-weight: bold;background-color: gray;text-decoration: none;
height: 40px;width: 100px;padding: 2px 10px 2px 10px;text-align: center;border: 2px solid yellow;}

</style>
</head>
<body>
<form id="form1" runat="server">
<table width="100%">
<tr>
<td align="center">
<strong>Data List Custom Paging</strong></td>
</tr>
<tr>
<td align="left">
<asp:DataList runat="server" ID="dListItems" RepeatColumns="2" CellPadding="2">
<ItemTemplate>
<%#Eval("title") %>
</ItemTemplate>
<AlternatingItemStyle BackColor="Silver" />
<ItemStyle BackColor="White" />
</asp:DataList>
</td>
</tr>
<tr>
<td>
 
</td>
</tr>
<tr>
<td>
<table style="background-color:green;" cellpadding="0" border="0">
<tr>
<td width="50px" align="right">
<asp:LinkButton ID="lbtnFirst" CssClass="btnlP" runat="server" CausesValidation="false" OnClick="lbtnFirst_Click">First</asp:LinkButton>
 </td>
<td width="50px" align="right">
<asp:LinkButton ID="lbtnPrevious" CssClass="btnlP" runat="server" CausesValidation="false" OnClick="lbtnPrevious_Click">Previous</asp:LinkButton>  </td>
<td width="200px" align="center" valign="middle">
<asp:DataList ID="dlPaging" runat="server" RepeatDirection="Horizontal" OnItemCommand="dlPaging_ItemCommand"
OnItemDataBound="dlPaging_ItemDataBound">
<ItemTemplate>
<asp:LinkButton CssClass="btnlink" ID="lnkbtnPaging" runat="server" CommandArgument='<%# Eval("PageIndex") %>'
CommandName="Paging" Text='<%# Eval("PageText") %>'></asp:LinkButton> 
</ItemTemplate>
</asp:DataList>
</td>
<td width="50px" align="left">
  <asp:LinkButton CssClass="btnlP" ID="lbtnNext" runat="server" CausesValidation="false"
OnClick="lbtnNext_Click">Next</asp:LinkButton></td>
<td width="50px" align="left">
 
<asp:LinkButton ID="lbtnLast" CssClass="btnlP" runat="server" CausesValidation="false" OnClick="lbtnLast_Click">Last</asp:LinkButton></td>
<td Class="shopage" width="100px" align="center" style="height: 30px" valign="middle">
<asp:Label ID="lblPageInfo" runat="server"></asp:Label></td>
</tr>

</table>
</td>
</tr>
</table>
</form>
</body>
</html>

=================

Code behind

==============

using System;

using System.Data;

using System.Configuration;

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;

public partial class _Default : System.Web.UI.Page

{

#region Private Properties

private int CurrentPage

{

get

{

object objPage = ViewState["_CurrentPage"];

int _CurrentPage = 0;

if (objPage == null)

{

_CurrentPage = 0;

}

else

{

_CurrentPage = (int)objPage;

}

return _CurrentPage;

}

set { ViewState["_CurrentPage"] = value; }

}

private int fistIndex

{

get

{

int _FirstIndex = 0;

if (ViewState["_FirstIndex"] == null)

{

_FirstIndex = 0;

}

else

{

_FirstIndex = Convert.ToInt32(ViewState["_FirstIndex"]);

}

return _FirstIndex;

}

set { ViewState["_FirstIndex"] = value; }

}

private int lastIndex

{

get

{

int _LastIndex = 0;

if (ViewState["_LastIndex"] == null)

{

_LastIndex = 0;

}

else

{

_LastIndex = Convert.ToInt32(ViewState["_LastIndex"]);

}

return _LastIndex;

}

set { ViewState["_LastIndex"] = value; }

}

#endregion

#region PagedDataSource

PagedDataSource _PageDataSource = new PagedDataSource();

#endregion

#region Private Methods

/// <summary>

/// Build DataTable to bind Main Items List

/// </summary>

/// <returns>DataTable</returns>

private DataTable GetDataTable()

{

DataTable dtItems = new DataTable();

DataColumn dcName = new DataColumn();

dcName.ColumnName = "title";

dcName.DataType = System.Type.GetType("System.String");

dtItems.Columns.Add(dcName);

DataRow row;

for (int i = 1; i <= 100; i++)

{

row = dtItems.NewRow();

row["title"] = "Sample Row: I am putting here sample text for row " + i;

dtItems.Rows.Add(row);

}

return dtItems;

}

/// <summary>

/// Binding Main Items List

/// </summary>

private void BindItemsList()

{

DataTable dataTable = this.GetDataTable();

_PageDataSource.DataSource = dataTable.DefaultView;

_PageDataSource.AllowPaging = true;

_PageDataSource.PageSize = 10;

_PageDataSource.CurrentPageIndex = CurrentPage;

ViewState["TotalPages"] = _PageDataSource.PageCount;

this.lblPageInfo.Text = "Page " + (CurrentPage + 1) + " of " + _PageDataSource.PageCount;

this.lbtnPrevious.Visible = !_PageDataSource.IsFirstPage;

this.lbtnNext.Visible = !_PageDataSource.IsLastPage;

this.lbtnFirst.Visible = !_PageDataSource.IsFirstPage;

this.lbtnLast.Visible = !_PageDataSource.IsLastPage;

this.dListItems.DataSource = _PageDataSource;

this.dListItems.DataBind();

this.doPaging();

}

/// <summary>

/// Binding Paging List

/// </summary>

private void doPaging()

{

DataTable dt = new DataTable();

dt.Columns.Add("PageIndex");

dt.Columns.Add("PageText");

fistIndex = CurrentPage -3;

if (CurrentPage > 3)

{

lastIndex = CurrentPage +3;

}

else

{

lastIndex = 5;

}

if (lastIndex > Convert.ToInt32(ViewState["TotalPages"]))

{

lastIndex = Convert.ToInt32(ViewState["TotalPages"]);

fistIndex = lastIndex - 5;

}

if (fistIndex < 0)

{

fistIndex = 0;

}

for (int i = fistIndex; i < lastIndex; i++)

{

DataRow dr = dt.NewRow();

dr[0] = i;

dr[1] = i + 1;

dt.Rows.Add(dr);

}

this.dlPaging.DataSource = dt;

this.dlPaging.DataBind();

}

#endregion

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

this.BindItemsList();

}

protected void lbtnNext_Click(object sender, EventArgs e)

{

CurrentPage += 1;

this.BindItemsList();

}

protected void lbtnPrevious_Click(object sender, EventArgs e)

{

CurrentPage -= 1;

this.BindItemsList();

}

protected void dlPaging_ItemCommand(object source, DataListCommandEventArgs e)

{

if (e.CommandName.Equals("Paging"))

{

CurrentPage = Convert.ToInt16(e.CommandArgument.ToString());

this.BindItemsList();

}

protected void dlPaging_ItemDataBound(object sender, DataListItemEventArgs e)

{

LinkButton lnkbtnPage = (LinkButton)e.Item.FindControl("lnkbtnPaging");

if (lnkbtnPage.CommandArgument.ToString() == CurrentPage.ToString())

{

lnkbtnPage.Enabled = false;

lnkbtnPage.Style.Add("fone-size", "14px");

lnkbtnPage.Font.Bold = true;

}

protected void lbtnLast_Click(object sender, EventArgs e)

{

CurrentPage = (Convert.ToInt32(ViewState["TotalPages"]) - 1);

this.BindItemsList();

}

protected void lbtnFirst_Click(object sender, EventArgs e)

{

CurrentPage = 0;

this.BindItemsList();

}

Interview Question

Thursday, May 22, 2014

How to custom paging in datalist?

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