DATALIST CONTROL IN ASP.NET 3.5

Datalist Control in ASP.Net
DataList is a data bound list control that displays items using certain templates defined at the design time. The content of the DataList control is manipulated by using templates sections such as AlternatingItemTemplate, EditItemTemplate, FooterTemplate, HeaderTemplate, ItemTemplate, SelectedItemTemplate and SeparatorTemplate. Each of these sections has its own characteristics to be defined but at a very minimum, the ItemTemplate needs to be defined to display the items in the DataList control. Other sections can be used to provide additional look and feel to the DataList control.



The contents of the DataList control can be manipulated by using templates. The following table lists the supported templates.
The DataList control displays data items in a repeating list, and optionally supports selecting and editing the items. The content and layout of list items in DataList is defined using templates. At a minimum, every DataList must define an ItemTemplate; however, several optional templates can be used to customize the appearance of the list.

AlternatingItemTemplate: If defined, provides the content and layout for alternating items in the DataList. If not defined, ItemTemplate is used.

EditItemTemplate: If defined, provides the content and layout for the item currently being edited in the DataList. If not defined, ItemTemplate is used.

FooterTemplate: If defined, provides the content and layout for the footer section of the DataList. If not defined, a footer section will not be displayed.

HeaderTemplate: If defined, provides the content and layout for the header section of the DataList. If not defined, a header section will not be displayed.

ItemTemplate: Required template that provides the content and layout for items in the DataList.

SelectedItemTemplate: If defined, provides the content and layout for the currently selected item in the DataList. If not defined, ItemTemplate is used.

SeparatorTemplate: If defined, provides the content and layout for the separator between items in the DataList. If not defined, a separator will not be displayed.

At the very minimum, the ItemTemplate needs to be defined to display the items in the DataList control. Additional templates can be used to provide a custom look to the DataList control.


The appearance of the DataList control may be customized by setting the style properties for the different parts of the control. The following table lists the different style properties.

AlternatingItemStyle: Specifies the style for alternating items in the DataList control.

EditItemStyle: Specifies the style for the item being edited in the DataList control.

FooterStyle: Specifies the style for the footer in the DataList control.

HeaderStyle: Specifies the style for the header in the DataList control.

ItemStyle: Specifies the style for the items in the DataList control.

SelectedItemStyle: Specifies the style for the selected item in the DataList control.

SeparatorStyle: Specifies the style for the separator between the items in the DataList control.

You can also show or hide different parts of the control. The following table lists the properties that control which parts are shown or hidden.

ShowFooter: Shows or hides the footer section of the DataList control.

ShowHeader: Shows or hides the header section of the DataList control.

The display direction of a DataList control can be vertical or horizontal. Set the RepeatDirection property to specify the display direction.
The layout of the DataList control is controlled with the RepeatLayout property. Setting this property to RepeatLayout.Table will display the DataList in a table format, while RepeatLayout.Flow displays the DataList without a table structure.

Lets we saw in detail.
To create a datalist oriented application we have to construct the templates.
That is ItemTemplate and EditItemTemplate.
ItemTemplate has been created in the following manner.

Similarly
Lets we saw an example Program..
In Default.aspx page Do the following.
<%@ 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>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<br />
<asp:DataList runat="server"
DataKeyField="ID"
ID="DataList1"
OnEditCommand="DataList1_EditCommand"
OnCancelCommand="DataList1_CancelCommand"
OnUpdateCommand="DataList1_UpdateCommand">
<EditItemTemplate>
ID: <asp:Label ID="Label1" runat="server"
Text='<%# Eval("ID") %>'>
</asp:Label>
<br />
Name: <asp:TextBox ID="textCategoryName" runat="server"
Text='<%# Eval("name") %>'>
</asp:TextBox>
<br />
Description: <asp:TextBox ID="textDescription"
runat="server"
Text='<%# Eval("description") %>'>
</asp:TextBox>
<br />
<asp:LinkButton ID="LinkButton1" runat="server"
CommandName="update" >
Save
</asp:LinkButton>
 
<asp:LinkButton ID="LinkButton2" runat="server" CommandName="cancel" >
Cancel
</asp:LinkButton>
</EditItemTemplate>
<ItemTemplate>
ID:
<asp:Label ID="IDLabel" runat="server"
Text='<%# Eval("ID") %>'></asp:Label>
<br />
name:
<asp:Label ID="nameLabel" runat="server"
Text='<%# Eval("name") %>'></asp:Label>
<br />
description:
<asp:Label ID="descriptionLabel" runat="server"
Text='<%# Eval("description") %>'></asp:Label>
<br />
<asp:LinkButton runat="server" ID="LinkButton1"
CommandName="edit" >
Edit
</asp:LinkButton><br />
<br />
</ItemTemplate>

</asp:DataList>
</div>
</form>
</body>
</html>

Now Go to Default.aspx.cs:

using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;

public partial class _Default : System.Web.UI.Page
{
SqlConnection sqlcon = new SqlConnection();
SqlCommand sqlcmd = new SqlCommand();
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
//Bind data to the Data List control when page load first time
bindList();
}
}
void bindList()
{
SqlConnection sqlcon = new SqlConnection();
SqlCommand sqlcmd = new SqlCommand();
sqlcon.ConnectionString = "data source=.;Initial Catalog=datagrid;uid=sa;password=hi";
//Open Sql server Connection
sqlcon.Open();
sqlcmd = new SqlCommand("select * from employ", sqlcon);
//Execute query and fill value in data table
SqlDataAdapter da;
da = new SqlDataAdapter(sqlcmd);
DataTable dt = new DataTable();
da.Fill(dt);
if (dt.Rows.Count > 0)
{
//Bind data into the DataList control
DataList1.DataSource = dt;
DataList1.DataBind();
}
//Close SQl Server Connection
sqlcon.Close();
}
protected void DataList1_EditCommand(object source, DataListCommandEventArgs e)
{
//Get Edit Item index when user click edit button
DataList1.EditItemIndex = e.Item.ItemIndex;
bindList();

}
protected void DataList1_CancelCommand(object source, DataListCommandEventArgs e)
{

//Leave it Item in default for reload DataList
DataList1.EditItemIndex = -1;
bindList();

}
protected void DataList1_UpdateCommand(object source, DataListCommandEventArgs e)
{
//Get User entered value in the Edit mode text boxes
string name = ((TextBox)e.Item.FindControl("textCategoryName")).Text;
string description = ((TextBox)e.Item.FindControl("textDescription")).Text;

//Get the Identity Primary DataKey value when user click update button
int eno = Convert.ToInt32(DataList1.DataKeys[e.Item.ItemIndex]);
sqlcmd = new SqlCommand("update employ set name='" + name + "',description='" + description + "' where ID='" + eno + "'", sqlcon);
sqlcon.ConnectionString = "data source=.;Initial Catalog=datagrid;uid=sa;password=1soft";
sqlcon.Open();
//Execute query to perform update operation on SQL Server
sqlcmd.ExecuteNonQuery();
sqlcon.Close();
//Set datalist default index -1 for display record
DataList1.EditItemIndex = -1;
//Bind new updated data on DataList control
bindList();

}
}

Dont Forgot to create the Database Table Design..
Happy Coding..

Data Caching in ASP.NET3.5 in DataList View..

Hai My readers,
In this post i will Give a sample program for data caching in asp.net3.5.
Finally i filled all the databound values into the Datalist.
Lets we see in details.

If you are using static data with your ASP.NET applications, such
as that from a database server like Microsoft SQL Server, you should take a
look at caching your data. Previously, this was not an easy thing to do, but the
caching in .NET makes caching your data and objects a trivial task.

In ASP.NET, every page you write extends the
System.Web.UI.Page class, which contains a member called Cache. You use the
Cache property as you would any other IEnumerable, which gives you methods and
properties to get, set, and enumerate through members. We will be looking at
getting and setting items in the cache. In the simplest example, you can
retrieve any object from the cache like so:

Object obj = (Object)Cache["key"];

What this does is look in the Cache for an item with the key "key".
If such an item exists, the object is returned. While we don't need to cast the
returned object to Object, this is just an example of how you must cast the
return to the class type you want returned. If the item is not found, null is
returned, so you will need to do some checking:

Object obj = (Object)Cache["key"];
if (obj == null) {
// Generate a new object and insert it into the cache
}
// Use your object

You can also assign object to the cache like the following code example, but
using Cache.Inset() is a much better means as you'll see later:

Cache["key"] = obj;

Lets We see in details..
Create a Page named Default.aspx and type the coding below..
<%@ 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>
<title>Cache Dependency Tester</title>
<meta content="Microsoft Visual Studio 7.0" name="GENERATOR" />
<meta content="C#" name="CODE_LANGUAGE" />
<meta content="JavaScript" name="vs_defaultClientScript" />
<meta content="http://schemas.microsoft.com/intellisense/ie5" name="vs_targetSchema" />
</head>
<body ms_positioning="GridLayout">
<form id="Form1" method="post" runat="server">
<asp:DataList id="dlUsers" style="Z-INDEX: 101; LEFT: 44px; POSITION: absolute; TOP: 104px" runat="server" Height="148px" Width="343px" BorderWidth="1px" GridLines="Horizontal" CellPadding="4" BackColor="White" ForeColor="Black" BorderStyle="None" BorderColor="#CCCCCC">
<SelectedItemStyle font-bold="True" forecolor="White" backcolor="#CC3333"></SelectedItemStyle>
<FooterStyle forecolor="Black" backcolor="#CCCC99"></FooterStyle>
<HeaderStyle font-bold="True" forecolor="White" backcolor="#333333"></HeaderStyle>
<ItemTemplate>
<table bgcolor="#CCCCFF" border="Black" cellspacing="20">
<tr>
<td><b>User_ID:</b><%#DataBinder.Eval(Container.DataItem,"UserId")%><br />
<b>First_Name:</b><%#DataBinder.Eval(Container.DataItem,"FirstName")%><br />
<b>Last_Name:</b><%#DataBinder.Eval(Container.DataItem,"LastName")%><br /></td>
<td>
</td>
<td>
</td>
</tr>
</table>
</ItemTemplate>
</asp:DataList>
<asp:Label id="lblChange" style="Z-INDEX: 102; LEFT: 46px; POSITION: absolute; TOP: 63px" runat="server" Height="28px" Width="295px"></asp:Label>
</form>
</body>
</html>

In that design page i drag and drop one datalist control and added the necessary template.

Goto Default.aspx.cs and type the following Code.
protected void Page_Load(object sender, EventArgs e)
{
DataSet dsUsers;
try
{
if(Cache["Users"]==null)
{
SqlConnection cn;
dsUsers = new DataSet("new");
cn = new SqlConnection("data source=.;Initial Catalog=restaurent;uid=sa;password=1soft;");
// cn = new SqlConnection(ConfigurationSettings.AppSettings.Get("conn"));
SqlDataAdapter daUsers;
daUsers = new SqlDataAdapter("Select * from tblUsers",cn);
cn.Open();
daUsers.Fill(dsUsers,"tblUsers");
//Update the cache object
Cache.Insert("Users",dsUsers, new System.Web.Caching.CacheDependency(
Server.MapPath("Master.xml")), DateTime.Now.AddSeconds(45),TimeSpan.Zero);
HttpContext.Current.Trace.Write(DateTime.Now.AddSeconds(45).ToString() + "is expiry time..");
cn.Close();
cn.Dispose();
HttpContext.Current.Trace.Write("from Database..");
lblChange.Text ="From the database....";
}
else
{
HttpContext.Current.Trace.Write("From cache..");
lblChange.Text ="From the cache....";
dsUsers= (DataSet) Cache["Users"];
}
dlUsers.DataSource =dsUsers;
dlUsers.DataMember = dsUsers.Tables[0].TableName ;
//lblChange.Text += Server.MapPath("Master.xml");
this.DataBind();
}
catch(Exception ex)
{
lblChange.Text = ex.Message;
}
}
Now run the prgram..and u get the desired output.
Happy Coding....