DOTNET

Sunday, August 26, 2012

ICALL BACK EVENT HANDLER

We have to play with 4 functions,

Two client side functions i.e. java script function,
JavaScript Functions
RaiseCallbackEvent function gets call automatically whenever there is a CallbackEvent. And after this function 2nd function i.e. GetCallbackResult get called automatically.
DataBase Design
<html xmlns="http://www.w3.org/1999/xhtml">
function ReceiveServerData(retValue) {
using System.Data.SqlClient;
public partial class AddPage : System.Web.UI.Page,ICallbackEventHandler
}
public void RaiseCallbackEvent(String eventArgument)
Output

Two server side function i.e. c# (in this case).

1 function ReceiveServerData(retValue)
2 function Checkusername

.cs functions

1 public void RaiseCallbackEvent(String eventArgument)

2 public String GetCallbackResult()

AddPage.aspx

<head runat="server">
<title></title>
<script type="text/javascript" language="javascript">
function Checkusername ()
{
var values = document.getElementById("txtEname").value;
CallServer(values, "");
}

if (retValue == "N") {
alert("Please select another name; empname already exists");
document.getElementById("txtEname").value = "";
document.getElementById("txtEname").focus();
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<table>
<tr>
<td>
<asp:Label ID="Label1" runat="server" Text="Eno"></asp:Label>
</td>
<td>
<asp:TextBox ID="txtEno" runat="server" ></asp:TextBox>
</td>
</tr>
<tr>
<td>
<asp:Label ID="Label2" runat="server" Text="Ename"></asp:Label>
</td>
<td>
<asp:TextBox ID="txtEname" runat="server" onblur="javascript:Checkusername()"></asp:TextBox>
</td>
</tr>
<tr>
<td>
<asp:Label ID="Label3" runat="server" Text="Designation"></asp:Label>
</td>
<td>
<asp:TextBox ID="txtDesignation" runat="server"></asp:TextBox>
</td>
</tr>
<tr>
<td colspan="2" align="center">
<asp:Button ID="btnSave" runat="server" Text="Save" onclick="btnSave_Click" />
</td>
</tr>
</table>
</div>
</form>
</body>
</html>

AddPage.aspx.cs

using System.Configuration;

{
protected String returnValue;
protected void Page_Load(object sender, EventArgs e)
{
String cbReference = Page.ClientScript.GetCallbackEventReference(this, "arg","ReceiveServerData", "context");
string callbackScript = "function CallServer(arg,context)" + "{" + cbReference + ";}";
Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "CallServer", callbackScript,true);
}
protected void btnSave_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection("user id=sa;password=uday;database=uday;data source=localhost");
con.Open();
SqlCommand cmd = new SqlCommand("insert into employee values(" + txtEno.Text + ",'" + txtEname.Text + "','" + txtDesignation.Text + "')", con);
int i=cmd.ExecuteNonQuery();
if(i>0)
{
Response.Redirect("Default.aspx");
}
con.Close();

{
SqlConnection con = new SqlConnection("user id=sa;password=uday;database=uday;data source=localhost");
SqlCommand com = new SqlCommand("select *from employee where ename='" +eventArgument + "'", con);
con.Open();
SqlDataReader dr;
dr = com.ExecuteReader();
if (dr.HasRows == true)
{
returnValue = "N";
}
else
{
returnValue = "Y";
}
con.Close();
}
public String GetCallbackResult()
{
return returnValue;
}
}

Monday, August 20, 2012

Working with JSON

JSON (JavaScript Object Notation) is one lightweight data exchange format.

You don’t need to download an additional library to serialize/deserialize your objects to/from JSON. Since .NET 3.5, .NET can do it natively.

Add a reference to your project to “System.Web.Extensions.dll”

File->New->Website

Add a Class(Static.cs)

Now write the Following Code in Static.cs
using System;
/// <summary>
public String Technologies()
public ArrayList EmpDetails()
public string JsonString()
Now Add New Item
Default.aspx
<html xmlns="http://www.w3.org/1999/xhtml">
Default.aspx.cs
using System.Web.UI;
public partial class Default3 : System.Web.UI.Page
Now Run
Paste the following output and Click on Viewer
using System.Web.UI;
public partial class Default3 : System.Web.UI.Page

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Script.Serialization;

using System.Collections;

/// Summary description for Static

/// </summary>

public class Static

{

JavaScriptSerializer jss = new JavaScriptSerializer();

{

string jsonString = string.Empty;

string[] courses = { "asp.net", "sqlserver", "silverlight", "sharepoint", "iPhone", "vb.net", "java", "php" };

Dictionary<string, string[]> dicEmpInfo = new Dictionary<string, string[]>();

dicEmpInfo.Add("Technologies", courses);

jsonString = jss.Serialize(dicEmpInfo);

return jsonString;

}

{

Dictionary<string, string> dicpersonalinfo = new Dictionary<string, string>();

dicpersonalinfo.Add("First Name", "Uday");

dicpersonalinfo.Add("LastName", "Kumar");

Dictionary<string, string> dicpersonalInfo2 = new Dictionary<string, string>();

dicpersonalInfo2.Add("FirstName", "Anvesh");

dicpersonalInfo2.Add("LastName", "G");

Dictionary<string, string> dicpersonalInfo3 = new Dictionary<string, string>();

dicpersonalInfo3.Add("FirstName", "Sunitha");

dicpersonalInfo3.Add("LastName", "Kumari");

Dictionary<string, string> dicpersonalInfo4 = new Dictionary<string, string>();

dicpersonalInfo4.Add("FirstName", "Badri");

dicpersonalInfo4.Add("LastName", "Nath");

ArrayList empDetails = new ArrayList();

empDetails.Add(dicpersonalinfo);

empDetails.Add(dicpersonalInfo2);

empDetails.Add(dicpersonalInfo3);

empDetails.Add(dicpersonalInfo4);

//string strJson = jss.Serialize(empDetails);

return empDetails;

}

{

string jsonString1 = string.Empty;

ArrayList arr = EmpDetails();

jsonString1 = jss.Serialize(arr);

return jsonString1;

}

</head>

<body>

<div>

</div>

</form>

</body>

</html>

using System.Web.UI.WebControls;

{

protected void Page_Load(object sender, EventArgs e)

{

Static obj = new Static();

string str = obj.Technologies();

Response.Write(str);

}

Now Go to

http://jsonviewer.stack.hu/

For Second Method in static.cs

Default.aspx.cs

using System.Web.UI.WebControls;

{

protected void Page_Load(object sender, EventArgs e)

{

Static obj = new Static();

string str = obj.Technologies();

// Response.Write(str);

string str1 = obj.JsonString();

Response.Write(str1);

}

copy the output and

Now Go to

http://jsonviewer.stack.hu/

Sunday, August 19, 2012

Encrypt and Decrypt Connection Strings in Web.Config

Encryption and Decryption using Web.Config

File->New->WebSite

Go to web.config file and write the following code.

<connectionStrings>
<add name="dbemployee" connectionString="Data Source=localhost; user id=sa;password=uday; database=uday"
providerName="System.Data.SqlClient" />
</connectionStrings>

Now go to Visual Stdio CommandPrompt and type the following to encypt the web.config file.

aspnet_regiis.exe -pef "connectionStrings" path of the file

Eg: aspnet_regiis.exe -pef "connectionStrings" C:\Users\uday\Documents\WebSite3

here pef indicates file system website.

Now go to web.config and see the web.config file with the encrypted code

Web.config

Decrypt the Connection String

Now go to Visual Stdio CommandPrompt and type the following to decrypt the web.config file

aspnet_regiis.exe -pdf "connectionStrings" path of the file

Eg: aspnet_regiis.exe -pdf "connectionStrings" C:\Users\uday\Documents\WebSite3

Web.config

Working with Cookies

Working with Cookies

Cookies : The information which is stored in Client Machine.

Syntax for creating the cookie
To create or retrieve information from cookie we have a class called as
1) HttpCookie object=new HttpCookie(cookiename, cookievalue);

Now to store the above cookie we have to write the next line asResponse.Cookies.Add(object);

2) HttpCookie object=new HttpCookie(cookiename);object.Value=cookie.value;Response.Cookies.Add(object);

Retrieving the information from a Cookie
Syntax1) HttpCookie object=Request.Cookies["Cookiename"];variable=object.Value;
2) variable=Request.Cookies["Cookiename"].value;

Cookies are classified into Two Types
1 In Memory Cookies2 Out Memory Cookies

In Memory Cookies: Are again classified into two types1 Single Value Cookie2 Multi Value Cookie
Out Memory Cookies:

Are again classified into two types1 Single Value Cookie2 Multi Value Cookie
InMemory Cookie:The cookies which are stored in the browser process memory are called as inmemory cookie.
These cookies will automatically destroy themselves when the browser is closed.so the default life span of the inmemory cookie is till the browser is on.

SingleValueCookie
Which stores only the single cookie is called as single value cookie.

Example
Default.aspx

Default.aspx.cs

Multi Value Cookie
A cookie which holds multiple values in a single name.

How to Create MultiValue Cookie

HttpCookie object=new HttpCookie(cookiename);
object.Values["key"]="value";
or
object.Values.Add("key","value1");
object.Values.Add("key","value2");

To Store the Cookie
Response.Cookies.Add(object);

To Retrieve information

HttpCookie object =Request.Cookies["CookieName"];

To get Count
Object.Values.Count

To get Keys
Object.Values.GetKey(index);

To get KeyValues
Object.Values[index];
Object.Values.Get(index);

Example
Default.aspx

Default.aspx.cs

Output

When Click on Create Cookie
It displays a Message as Cookie Created.

When Click on Display Cookie

Out Memory Cookie

A cookie which is stored permanently on the hard disc of a client machine .

Syntax for Creating Single Value Cookie

HttpCookie obj=new HttpCookie("cookiename");

obj.Value=someValue;

obj.Expires=DateTime.Now.AddMinutes();

Supported Methods

AddSeconds();

AddHours();

AddMonths();

AddYears();

AddDays();

DateTime.MaxValue

To Store Cookie in the Hard Disc

Response.Cookies.Add(object);

Default.aspx

<table>
<tr>
<td>
<asp:Label ID="Label1" runat="server" Text="UserName"></asp:Label>
</td>
<td>
<asp:TextBox ID="txtUserName" runat="server"></asp:TextBox>
</td>
</tr>
<tr>
<td>
<asp:Label ID="Label2" runat="server" Text="Password"></asp:Label>
</td>
<td>
<asp:TextBox ID="txtPassword" runat="server"></asp:TextBox>
</td>
</tr>
<tr>
<td colspan="2">
<asp:CheckBox ID="CheckBox1" runat="server" Text="Remember UserName & Password"/>
</td>
</tr>
<tr>
<td colspan="2">
<asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" />
</td>
</tr>
</table>

Default.aspx.cs

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (Request.Cookies["username"] != null && Request.Cookies["password"] != null)
{
if (Request.Cookies["username"].Value.ToString() == "uday" && Request.Cookies["password"].Value.ToString() == "uday")
{

Response.Redirect("Default2.aspx");
}
}
}

protected void Button1_Click(object sender, EventArgs e)
{
if (txtUserName.Text == "uday" && txtPassword.Text == "uday")
{
if (CheckBox1.Checked == true)
{
HttpCookie cookie = new HttpCookie("username", txtUserName.Text);
cookie.Expires = DateTime.MaxValue;
HttpCookie p = new HttpCookie("password", txtPassword.Text);
p.Expires = DateTime.MaxValue;
Response.Cookies.Add(cookie);
Response.Cookies.Add(p);
}
}
}
}

Output

________________________________________________________________

Example for writing the cookies

Response.Cookies["uday"].Value = "abc";
Response.Cookies["uday"].Expires = DateTime.Now.AddDays(1);
_________________________________________________________________________________

HttpCookie anvesh= new HttpCookie("goud");
anvesh.Value = DateTime.Now.ToString();
anvesh.Expires = DateTime.Now.AddDays(1);Response.Cookies.Add(anvesh);
__________________________________________________________

Reading Cookies

if(Request.Cookies["uday"] != null)
lblCookie.Text = Server.HtmlEncode(Request.Cookies["uday"].Value);
__________________________________________________________

Deleting Cookies
HttpCookie demoCookie = new HttpCookie("uday");demoCookie.Value = DateTime.Now.ToString();demoCookie.Expires = DateTime.Now.AddDays(-1);Response.Cookies.Add(uday);
________________________________________________________________

Advantages

1 Cookies are stored on client.
2 Easy to Implement
3. You can configure cookies to expire when the browser session ends (session cookies) or they can exist for a specified length of time on the client computer (persistent cookies).

Disadvantages

1 User can delete cookie

2 No Security

Wednesday, August 15, 2012

GridView using ArrayList

ArrayList

It is the set of Dissimilar data types.

It is under System.Collections NameSpace

Default.aspx

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:GridView ID="GridView1" runat="server">
</asp:GridView>
</div>
</form>
</body>
</html>

Default.aspx.cs

using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
Data();
}
}
private void Data()
{
string[] arrlist = { "uday","raju","anvesh","kittu","sandhya" };
DataTable dt = new DataTable();
dt.Columns.Add("Name");
for (int i = 0; i < arrlist.Count(); i++)
{
dt.Rows.Add();
dt.Rows[i]["Name"] = arrlist[i].ToString();
}
GridView1.DataSource = dt;
GridView1.DataBind();
}
}

Output