How to call javascript and jquery function from code behind in ASP.net and c#

Introduction: Here I will tell you how you can call javascript and jquery function 

from codebehind.

Descirption:
Here I will tell you how you can call javascript and jquery function from codebehind.

If you are using scriptmanager on page then you can call

ScriptManager instance.

If you are not using script manager then you can call 

Page.ClientScript instance

Implementation:

In Code Behind 

protected void MyButton_Click(object sender, EventArgs e)
{
    Page.ClientScript.RegisterStartupScript(this.GetType(), "myScript", 

 "MyFunction();", true);
} 

protected void MyButton_Click(object sender, EventArgs e)
{
    ScriptManager.RegisterStartupScript(this.GetType(), "myScript", 

  "MyFunction();", true);
} 

Abstract classes in C#.NET, VB.NET

Introduction: Abstract classes are those classes that can not be instantiated, but they can be inherited by 
other classes.
Description: Abstract classes are those classes that can not be instantiated, but they can be inherited by 
other classes. Abstract classes are base classes and inherited classes are called derived classes.
Abstract class can have both abstract and non abstract method in it. 
When to use: It is use to give common functionality to all inherited classes. it works like a base class.
Implementation:
abstract class MyShapes
{ 
abstract public int MyArea();
}
class Square : MyShapes
{
int side = 0;
 public Square(int n)
{ 
side = n; 
}
// Override Area method
public override int MyArea()
{ 
return side * side; 
}
}
class Rectangle : MyShapes
{
int length = 0, width=0;
public Rectangle (int length, int width)
{
this.length = length;
this.width = width;
// Override Area method 
public override int MyArea()
{ 
return length * width; 
}
}

Call web method from page using jquery and ajax without postback

Introduction: In this article I will show you how to call webmethod from aspx page using jquery
and ajax without postback.

Description:  Call webmethod from aspx page using jquery and ajax without postback.

In Aspx Page:

<head runat="server">
    <title></title>
<script src="scripts/jquery-1.3.2.min.js" type="text/javascript"></script>
<script type = "text/javascript">
function ShowTime() {
    $.ajax({
        type: "POST",
        url: "CS.aspx/GetTime",
        data: '{name: "' + $("#<%=txtName.ClientID%>")[0].value + '" }',
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: OnSuccess,
        failure: function(response) {
            alert(response.d);
        }
    });
}
function OnSuccess(response) {
    alert(response.d);
}
</script>
</head>
<body style = "font-family:Arial; font-size:10pt">
<form id="form1" runat="server">
<div>
Your Name :
<asp:TextBox ID="txtName" runat="server"></asp:TextBox>
<input id="btnGetTime" type="button" value="Show Current Time"
    onclick = "ShowCurrentTime()" />
</div>
</form>
</body>

In Code Behind:

[System.Web.Services.WebMethod]
public static string GetCurrentTime(string name)
{
    return "Hello " + name + Environment.NewLine + "The Current Time is: "
        + DateTime.Now.ToString();
}

How to change SQL server database mode from single user to multiuser and multi user to single user

Introduction: In this example you can set database mode to single user or multiuser

Description: Here you will see how to change database mode to single and multiuser.

Implementation:

Set Multi User Mode  to Single User Mode

USE MASTER;
GO
ALTER DATABASE [databasename] SET SINGLE_USER

Set Single User Mode to Multi User Mode 

USE MASTER;
GO
ALTER DATABASE [databasename] SET MULTI_USER

Bind Asp.net Dropdownlist from database in C#, VB.net

Introduction: Here I will explain how to bind dropdownlist from database.
Description: Today I will show you how to bind dropdownlist static and from database also I will
explain you how to find data in dropdownlist by text and by value.
Before implement this example we need database

Column Name	DataType	AllowNulls
UserId	Int(set identity true)	No
UserName	VarChar(50)	Yes
Location	VarChar(50)	Yes

Once table is designed write below code to your aspx page

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

<title>how to show data in dropdownlist from database in asp.net</title>

</head>

<body>

<form id="form1" runat="server">

<div>

<b>Selected UserName:</b>

<asp:DropDownList ID="ddlUser" runat="server" />

</div>

</form>

</body>

</html


Now add the following namespace to code behind

C# code

using System;

using System.Data;

using System.Data.SqlClient;

using System.Web.UI.WebControls;

After add namespace write the following code to code behind

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

BindUserdropdown();

}

}

/// <summary>

/// Bind Userdropdown

/// </summary>

protected voidBindUserdropdown ()

{

//conenction path for database

using (SqlConnection con = new SqlConnection("Data Source=Manoj;Integrated Security=true;Initial Catalog=MySchool"))

{

con.Open();

SqlCommand cmd = new SqlCommand("Select UserId,UserName FROM UserInformation", con);

SqlDataAdapter da = new SqlDataAdapter(cmd);

DataSet ds = new DataSet();

da.Fill(ds);

ddlUser.DataSource = ds;

ddlUser.DataTextField = "UserName";

ddlUser.DataValueField = "UserId";

ddlUser.DataBind();

ddlUser.Items.Insert(0, new ListItem("--Select--", "0"));

con.Close();

}

}
VB.Net Code 
 

Imports System.Data

Imports System.Data.SqlClient

Imports System.Web.UI.WebControls

Partial Class VBSample

Inherits System.Web.UI.Page

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load

If Not IsPostBack Then

BindUserdropdown()

End If

End Sub

''' <summary>

''' Bind UserDropdownlist

''' </summary>

Protected SubBindUserdropdown ()

'conenction path for database

Using con As New SqlConnection("Data Source=Manoj;Integrated Security=true;Initial Catalog=MySchool")

con.Open()

Dim cmd As New SqlCommand("Select UserId,UserName FROM UserInformation", con)

Dim da As New SqlDataAdapter(cmd)

Dim ds As New DataSet()

da.Fill(ds)

ddlUser.DataSource = ds

ddlUser.DataTextField = "UserName"

ddlUser.DataValueField = "UserId"

ddlUser.DataBind()

ddlUser.Items.Insert(0, New ListItem("--Select--", "0"))

con.Close()

End Using

End Sub

End Class
 

Compress and Extract files to zip in Asp.net C#

using System;
using System.IO;
using System.IO.Compression;

namespace ConsoleApplicationZip
{
    class Program
    {
        static void Main(string[] args)
        {
            string startPath = @"c:\example\source";
            string zipPath = @"c:\example\source\result.zip";
            string extractPath = @"c:\example\destination";

            ZipFile.CreateFromDirectory(startPath, zipPath);

            ZipFile.ExtractToDirectory(zipPath, extractPath);
        }
    }
}

Dialog Boxes in JavaScript(Alert, Prompt, Confirm)

Alert Dialog Box:
Alert dialog box is used to give alert on validation or other condition.

<head>
<script type="text/javascript">
<!--
   alert("Please enter value");
//-->
</script>
</head>

Confirm Dialog box:

This box is used to confirm for any condition 

<head>
<script type="text/javascript">
<!--
   var result= confirm("Are you sure to delete?");
   if( result== true ){
      alert("User wants to delete!");
   return true;
   }else{
      alert("User does not want to delete!");
   return false;
   }
//-->
</script>
</head>

Prompt Dialog Box:

This prompt dialog box is used to get user input on text box.

<head>
<script type="text/javascript">
<!--
   var result= prompt("please enter your name : ", "enter your name here");
   alert("You have entered : " +  result);
//-->
</script>
</head>