Captcha Control In Asp.net

Captcha Control In Asp.net


Hi Friends,
Here i will explain you how to implement captcha control in asp.net.


ON ASPX  PAGE :-
Paste below Script in your form tag.

<div>
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <table>
                    <tr>
                        <td style="height: 50px; width: 100px;">
                            <asp:Image ID="imgCaptcha" runat="server" />
                        </td>
                        <td valign="middle">
                            <asp:Button ID="btnRefresh" runat="server" Text="Refresh" OnClick="btnRefresh_Click" />
                        </td>
                    </tr>
                </table>
            </ContentTemplate>
        </asp:UpdatePanel>
        Enter Captcha:
        <asp:TextBox ID="txtCaptcha" runat="server"></asp:TextBox><br />
        <asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="btnSubmit_Click" />
        <asp:Label ID="lblmsg" runat="server"></asp:Label>
    </div>

ON CODE BEHIND ASPX.CS :-

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Text;
using System.Drawing.Imaging;  


protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                FillCaptcha();
            }
        }

        public void FillCaptcha()
        {
            try
            {
                Random random = new Random();
                string combination = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
                StringBuilder captcha = new StringBuilder();
                for (int i = 0; i < 6; i++)
                    captcha.Append(combination[random.Next(combination.Length)]);
                Session["captcha"] = captcha.ToString();
                imgCaptcha.ImageUrl = "GenerateCaptcha.aspx";
            }
            catch
            {

                throw;
            }
        }

        protected void btnRefresh_Click(object sender, EventArgs e)
        {
            FillCaptcha();
        }

        protected void btnSubmit_Click(object sender, EventArgs e)
        {
            if (Session["captcha"].ToString() != txtCaptcha.Text)
            {
                lblmsg.ForeColor = System.Drawing.Color.Red;
                lblmsg.Text = "Enter Valid Captcha Code";
            }
            else
            {
                lblmsg.ForeColor = System.Drawing.Color.Green;
                lblmsg.Text = "Enter code is correct";
            }
            FillCaptcha();
        }


Add one new aspx page GenerateCaptcha.aspx 

On code behind


using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging; 

 protected void Page_Load(object sender, EventArgs e)
        {
            Response.Clear();
            int height = 40;
            int width = 110;
            Bitmap bmp = new Bitmap(width, height);
            RectangleF rectf = new RectangleF(12, 6, 0, 0);
            Graphics g = Graphics.FromImage(bmp);
            g.Clear(Color.White);
            g.SmoothingMode = SmoothingMode.AntiAlias;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.PixelOffsetMode = PixelOffsetMode.HighQuality;
            g.DrawString(Session["captcha"].ToString(), new Font("Cambria", 13, FontStyle.Bold), Brushes.Red, rectf);
            g.DrawRectangle(new Pen(Color.Green), 1, 1, width - 15, height - 10);
            g.Flush();
            Response.ContentType = "image/jpeg";
            bmp.Save(Response.OutputStream, ImageFormat.Jpeg);
            g.Dispose();
            bmp.Dispose();
        }

 

Grid View Progress Bar Using Jquery

Grid View Progress Bar Using Jquery.

Hi Friends,
Here i will explain you how to implement Grid View Progress Bar Using Jquery.

ON ASPX  PAGE :-
Paste below Script in your head tag.

<script type="text/javascript" src="http://code.jquery.com/jquery-1.8.2.js"></script>  
    <script type="text/javascript">
        $(function () {
            $('#btnClick').click(function () {
                $('#Div').fadeTo('slow', .2);
                $('#Div').append('<img src="../Images/animated.gif" style="background-color:Aqua;position:fixed; top:20%; left:16%;"/></div>');
                setTimeout(function () { GetData() }, 800)
            })
        });
        function GetData() {
            $.ajax({
                type: "POST",
                contentType: "application/json; charset=utf-8",
                url: "JqueryProgressBar.aspx/filldatagrid",
                data: "{}",
                dataType: "json",
                success: function (data) {
                    var theHtml = data.d;
                    $('#Griddiv').html(theHtml)
                    $('#Div').html("");
                },
                error: function (result) {
                    alert("Error");
                }
            });
        }
    </script>

Paste below code in  form tag.

<div id="Div">
    </div>
    <input type="button" id="btnClick" value="GridView" />
    <div id="Griddiv">
    </div>

ON CODE BEHIND ASPX.CS :-

[WebMethod]
        public static string filldatagrid()
        {
            GridView gv = new GridView();
            System.IO.StringWriter stringWriter = new System.IO.StringWriter();
            HtmlTextWriter htmlWriter = new HtmlTextWriter(stringWriter);
            DataSet ds = manager.GetRecords();//Function for getting records
            DataTable dt = ds.Tables[0];
            gv.DataSource = dt;
            gv.DataBind();
            gv.RenderControl(htmlWriter);
            return stringWriter.ToString();
        }

CREATE A STORED PROCEDURE :-
CREATE PROCEDURE [dbo].[usp_SelectRegistration]
   
AS
BEGIN
    SELECT Pid ,FullName,CONVERT(varchar(30),DOB,101) AS DOB,Gender
    FROM form Order by Pid
END
ON BUSINESS LAYER MANAGER CLASS :- On your bussiness layer paste code below
 public static DataSet GetRecords()
        {

            return BusinessLayer.Dataaccess.DataAccess.GetData("usp_SelectRegistration", null);
        } //usp_SelectRegistration is stored procedure name //DataAccess is class in dataaccess layer //GetData is function for getting data using connection string
ON DATAACCESS LAYER :-
public static DataSet GetData(string SPName, List<SqlParameter> Parameters)
        {
            using (SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    cmd.CommandText = SPName;
                    cmd.CommandType = System.Data.CommandType.StoredProcedure;
                    cmd.Connection = con;

                    if (Parameters != null)
                    {
                        foreach (SqlParameter parameter in Parameters)
                        {
                            cmd.Parameters.Add(parameter);
                        }
                    }
                    con.Open();
                    DataSet ds = new DataSet();
                    SqlDataAdapter da = new SqlDataAdapter();
                    da.SelectCommand = cmd;
                    da.Fill(ds);
                    con.Close();
                    return ds;
                }
            }
        }
ON WEB.CONFIG :- Now add connection string in your webconfig,add code below..
<connectionStrings>
    <add name="ApplicationServices" connectionString="Data Source=10.1.1.1;Initial Catalog=DailyTaskoskar;Persist Security Info=True;User ID=Username;Password=Password" providerName="System.Data.SqlClient"/>
   
  </connectionStrings>

GridView Paging And Sorting And Showing Ascending And Descending Sorting Arrow Image with Header text In ASP.NET

Grid View Paging And Sorting And Showing Ascending And Descending Sorting Arrow Image with Header text  In ASP.NET  

Hi Friends,

Here i will explain you how to implement Grid View Paging And Sorting And Showing Ascending And Descending Sorting Arrow Image with Header text  In ASP.NET .

First of all create a table name it form 

Add some entries in form table

ON ASPX PAGE :-
In between header paste

<style type="text/css">
        th a
        {
            text-decoration: none;
        }
        .PagerControl
        {
            text-decoration: none;
        }
    </style>

In between form tage paste code below

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false"
        AllowPaging="true" PageSize="5" OnSorting="GridView1_Sorting" OnRowDataBound="GridView1_RowDataBound"
        AllowSorting="true" OnPageIndexChanging="GridView1_PageIndexChanging" HeaderStyle-Font-Names="Verdana"
        Font-Size="Small" HeaderStyle-HorizontalAlign="Left" HeaderStyle-Font-Underline="false"
        HeaderStyle-BackColor="BurlyWood" HeaderStyle-ForeColor="Navy">
        <AlternatingRowStyle BackColor="Aquamarine" />
        <PagerStyle CssClass="PagerControl"/>
        <Columns>
            <asp:BoundField DataField="fullname" HeaderText="fullname" SortExpression="fullname" />
            <asp:BoundField DataField="DOB" HeaderText="DOB" SortExpression="DOB" />
            <asp:BoundField DataField="Gender" HeaderText="Gender" SortExpression="Gender" />
                    </Columns>
    </asp:GridView>

ON CODE BEHIND ASPX.CS :-

Add namespaces

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using BusinessLayer.Entity;
using BusinessLayer.Manager;
using BusinessLayer.Dataaccess;
using System.Drawing;
using System.Text;
using System.IO;
using System.Drawing.Imaging;

# region Sorting

         public string sortingOrder
        {
            get
            {
                if (ViewState["sortingOrder"] == null)
                {
                    ViewState["sortingOrder"] = "desc";
                }
                return ViewState["sortingOrder"].ToString();
            }
            set
            {
                ViewState["sortingOrder"] = value;
            }

        }

        public string SortColumn
        {
            get
            {
                return (ViewState["SortColumn"] == null ? "fullname" : ViewState["SortColumn"].ToString());
            }
            set
            {
                ViewState["SortColumn"] = value;
            }
        }

         public SortDirection sortDirection
        {
            get
            {
                if (ViewState["sortDirection"] == null)
                {
                    ViewState["sortDirection"] = SortDirection.Ascending;
                }
                return (SortDirection)ViewState["sortDirection"];//.Descending;
            }
            set
            {
                ViewState["sortDirection"] = value;
            }
        }

        #endregion

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                fillDataGrid();
            }
        }
        public void fillDataGrid()
        {     
            DataSet ds = manager.GetRecords();//function for getting records from database written on bussiness layer manager.
            DataTable dt = ds.Tables[0];
            if (ds.Tables[0].Rows.Count == 0)
            {
                GridView1.DataSource = null;
                GridView1.DataBind();
            }
            else
            {
                DataView dv1 = new DataView(dt);
                dv1.Sort = SortColumn + " " + sortingOrder;
                GridView1.DataSource = dv1;
                GridView1.DataBind();
                GridView1.HeaderRow.Font.Underline = false;
            }
        }       

        protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
        {

            if (sortDirection == SortDirection.Descending)
            {
                sortDirection = SortDirection.Ascending;
            }
            else
            {
                sortDirection = SortDirection.Descending;
            }
            sortingOrder = (sortDirection == SortDirection.Descending) ? "asc" : "desc";
            SortColumn = e.SortExpression;
            fillDataGrid();
        }

        protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            string AscGvDeleteRecdords = @" <img src='../Images/white-triangle-up.png' Width='11px' Height='11px'  title='Ascending' />";
            string DesGvDeleteRecdords = @" <img src='../Images/white-triangle-down.png'Width='11px' Height='11px' title='Descendng' />";
            if (e.Row.RowType == DataControlRowType.Header)
            {
                foreach (TableCell cell in e.Row.Cells)
                {
                    if (cell.HasControls())
                    {
                        LinkButton lbl = (LinkButton)cell.Controls[0];
                        if (lbl.Text == SortColumn)
                        {
                            if (sortingOrder == "asc")
                            {
                                lbl.Text += AscGvDeleteRecdords;
                            }
                            else
                            {
                                lbl.Text += DesGvDeleteRecdords;
                            }
                        }
                    }
                }
            }
        }

        protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            GridView1.PageIndex = e.NewPageIndex;
            fillDataGrid();
        }

CREATE A STORED PROCEDURE :-

CREATE PROCEDURE [dbo].[usp_SelectRegistration]
   
AS
BEGIN
    SELECT Pid ,FullName,CONVERT(varchar(30),DOB,101) AS DOB,Gender
    FROM form Order by Pid
END

ON BUSINESS LAYER MANAGER CLASS :-
On your bussiness layer paste code below

 public static DataSet GetRecords()
        {

            return BusinessLayer.Dataaccess.DataAccess.GetData("usp_SelectRegistration", null);
        }
//usp_SelectRegistration is stored procedure name
//DataAccess is class in dataaccess layer
//GetData is function for getting data using connection string

ON DATAACCESS LAYER :-

public static DataSet GetData(string SPName, List<SqlParameter> Parameters)
        {
            using (SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    cmd.CommandText = SPName;
                    cmd.CommandType = System.Data.CommandType.StoredProcedure;
                    cmd.Connection = con;

                    if (Parameters != null)
                    {
                        foreach (SqlParameter parameter in Parameters)
                        {
                            cmd.Parameters.Add(parameter);
                        }
                    }
                    con.Open();
                    DataSet ds = new DataSet();
                    SqlDataAdapter da = new SqlDataAdapter();
                    da.SelectCommand = cmd;
                    da.Fill(ds);
                    con.Close();
                    return ds;
                }
            }
        }

ON WEB.CONFIG :-
Now add connection string in your webconfig,add code below..

<connectionStrings>
    <add name="ApplicationServices" connectionString="Data Source=10.1.1.1;Initial Catalog=DailyTaskoskar;Persist Security Info=True;User ID=Username;Password=Password" providerName="System.Data.SqlClient"/>
   
  </connectionStrings>

Simple Cryptography encryption and decryption in ASP.Net using C#

Hi Friends,

Here i will explane you encryption and decryption cryptography in asp.net using C#.

Firstly you have to know about cryptography.

The transformation of data in order to hide its information content, prevent its undetected modification, or prevent its unauthorized use.

The conversion of data into a secret code for protection of privacy using a specific algorithm and a secret key. The original text, or "plaintext", is converted into a coded equivalent called "ciphertext" via an encryption algorithm. The ciphertext can only be decoded (decrypted) using a predefined secret key.

ON ASPX PAGE :- paste the code

<table style=" padding:20px; line-height:40px;">
        <tr>
            <td colspan="2" align="center">
                <asp:Label ID="Label1" runat="server" Text="Encryption" Font-Size="Larger" ForeColor="Red"></asp:Label>
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label ID="Label2" runat="server" Text="Original Text:"></asp:Label>
            </td>
            <td>
                <asp:TextBox ID="txtOriginalText" runat="server" Text="" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label ID="Label3" runat="server" Text="Encrypted Text:"></asp:Label>
            </td>
            <td>
                <asp:Label ID="lblEncryptedText" runat="server" Text="" Font-Bold="true" />
            </td>
        </tr>
        <tr>
            <td colspan="2">
                <asp:Button ID="btnEncryption" Text="Encryption" runat="server" OnClick="btnEncryption_Click" />
            </td>
        </tr>
        <tr>
            <td>
            </td>
            <td>
            </td>
        </tr>
         <tr>
            <td>
            </td>
            <td>
            </td>
        </tr>
        <tr>
            <td colspan="2" align="center">
                <asp:Label ID="Label4" runat="server" Text="Decryption" Font-Size="Larger" ForeColor="Red"></asp:Label>
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label ID="Label5" runat="server" Text="Encrypted Text:"></asp:Label>
            </td>
            <td>
                <asp:TextBox ID="txtEncryptedText" runat="server" Text="" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label ID="Label6" runat="server" Text="Decrypted Text:"></asp:Label>
            </td>
            <td>
                <asp:Label ID="lblDecryptedText" runat="server" Text="" Font-Bold="true" />
            </td>
        </tr>
        <tr>
            <td colspan="2">
                <asp:Button ID="btnDecryption" Text="Decryption" runat="server" OnClick="btnDecryption_Click" />
            </td>
        </tr>
    </table>

ON CODE BEHIND ASPX.CS :- 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Text;
using System.Security.Cryptography;

protected void btnEncryption_Click(object sender, EventArgs e)
        {
            lblEncryptedText.Text = this.btnEncryption_Click(txtOriginalText.Text.Trim());
        }

        private string btnEncryption_Click(string clearText)
        {
            string EncryptionKey = "MAKV2SPBNI99212";
            byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);
            using (Aes encryptor = Aes.Create())
            {
                Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
                encryptor.Key = pdb.GetBytes(32);
                encryptor.IV = pdb.GetBytes(16);
                using (MemoryStream ms = new MemoryStream())
                {
                    using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(clearBytes, 0, clearBytes.Length);
                        cs.Close();
                    }
                    clearText = Convert.ToBase64String(ms.ToArray());
                }
            }
            return clearText;
        }



        protected void btnDecryption_Click(object sender, EventArgs e)
        {
            lblDecryptedText.Text = this.btnDecryption_Click(txtEncryptedText.Text.Trim());
        }

        private string btnDecryption_Click(string cipherText)
        {
            string EncryptionKey = "MAKV2SPBNI99212";
            byte[] cipherBytes = Convert.FromBase64String(cipherText);
            using (Aes encryptor = Aes.Create())
            {
                Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
                encryptor.Key = pdb.GetBytes(32);
                encryptor.IV = pdb.GetBytes(16);
                using (MemoryStream ms = new MemoryStream())
                {
                    using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateDecryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(cipherBytes, 0, cipherBytes.Length);
                        cs.Close();
                    }
                    cipherText = Encoding.Unicode.GetString(ms.ToArray());
                }
            }
            return cipherText;
        }

 

How to stop auto-fill in browsers for textbox using asp.net

Hi Friends,

Here I will explain how to stop auto-fill in browsers for textbox using asp.net.

• You can turn off auto-fill for a particular TextBox by setting autocomplete attribute value to off as shown below:

     <asp:TextBox Runat="server" ID="txtfname" autocomplete="off">

     </asp:TextBox> 

• You can turn off auto-fill for our complete form by setting autocomplete attribute value to off as shown below: 

         <form id="Form1" method="post" runat="server" autocomplete="off"> 
         .
         .
         </form>

• You can also do this from code behind like below: 

    txtfname.Attributes.Add("autocomplete", "off"); 

 

Simple WCF service example for beginners.

Hi Friends,

Here I will explain what WCF (windows communication foundation) is,and how to implement simple example to understand,How to use WCf Service.

What WCF is ?

Windows Communication Foundation (WCF) is a technology for developing applications based on service-oriented architecture (SOA). WCF is implemented using a set of classes placed on top of the .NET Common Language Runtime (CLR). It addresses the problem of interoperability using .NET for distributed applications.

WCF is entirely based on the .NET framework. It is primarily implemented as a set of classes that correspond to the CLR in the .NET framework. However, WCF allows .NET application developers to build service-oriented applications. The WCF client uses Simple Object Access Protocol (SOAP) to communicate with the server. The client and server are independent of the operating system, hardware and programming platform, and communication takes place at a high level of abstraction.

Creating a simple WCF Service :-

Once you create application you got in solution explorer like below 

Now double click on Iservice1.cs and paste code below

 [ServiceContract]
    public interface IService1
    {
        [OperationContract]
        string SampleMethod(string Name);
    } 

 Now double click on service1.svc and paste code below

public class Service1 : IService1
    {
        public string SampleMethod(string Name)
        {
            return "Hello " + Name + " Welcome to your first WCF program";
        }
    } 

Know Press F5 and build solution

 Know right click on service1.svc and view in browser and copy url.

Now for calling your first WCF service take another new project.
To call WCF service there are many ways like using console app, windows app and web app but here I am going for console application.

Name it FirstWCFServiceConsole

 
After it in Solution explorer Right-Click on Add References and Click on Add Service refrences.

Window apperes like below paste url which you copies early in service view in browser.

Now paste code in Program.cs like below

ServiceReference1.Service1Client objService = new ServiceReference1.Service1Client();
            Console.WriteLine("Please Enter your Name");
            string Message = objService.SampleMethod(Console.ReadLine());
            Console.WriteLine(Message);
            Console.ReadLine();

 Now open app.config paste copied url in endpoint address="" like below

 
Now the console application

Ajax Cascading Dependent Dropdown list Bind from Database.

Hi Friends,

Here I will explain how to use Cascading dropdownlist with database using asp.net

First of all add three tables like below..

Country

State

City

After this add reference of AjaxControlToolKit.dll and AjaxMin.dll in you solution References like below,remeber both dll file must be added to references.

ON ASPX PAGE :-

Add Code code like below

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>

<asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
    </asp:ToolkitScriptManager>
    <div>
        <table>
            <tr>
                <td>
                    Select Country:
                </td>
                <td>
                    <asp:DropDownList ID="ddlcountry" runat="server">
                    </asp:DropDownList>
                    <asp:CascadingDropDown ID="ccdCountry" runat="server" Category="Country" TargetControlID="ddlcountry"
                        PromptText="Select Country" LoadingText="Loading Countries.." ServiceMethod="BindCountryDetails"
                        ServicePath="~/AjaxCascadingDropDown.asmx">
                    </asp:CascadingDropDown>
                </td>
            </tr>
            <tr>
                <td>
                    Select State:
                </td>
                <td>
                    <asp:DropDownList ID="ddlState" runat="server">
                    </asp:DropDownList>
                    <asp:CascadingDropDown ID="ccdState" runat="server" Category="State" ParentControlID="ddlcountry"
                        TargetControlID="ddlState" PromptText="Select State" LoadingText="Loading States.."
                        ServiceMethod="BindStateDetails" ServicePath="~/AjaxCascadingDropDown.asmx">
                    </asp:CascadingDropDown>
                </td>
            </tr>
            <tr>
                <td>
                    Select Region:
                </td>
                <td>
                   <asp:DropDownList ID="ddlCity" runat="server">
                    </asp:DropDownList>
                     <asp:CascadingDropDown ID="ccdCity" runat="server" Category="City" ParentControlID="ddlState"
                        TargetControlID="ddlCity" PromptText="Select City" LoadingText="Loading City.."
                        ServiceMethod="BindCityDetails" ServicePath="~/AjaxCascadingDropDown.asmx">
                    </asp:CascadingDropDown>
                </td>
            </tr>
        </table>
    </div>
    
Now add a webservice in your project and name it  AjaxCascadingDropDown.asmx

Now open web service and paste namespaces like below

using System;
using System.Collections;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Data.SqlClient;
using System.Collections.Generic;
using System.Collections.Specialized;
using AjaxControlToolkit;
using System.Configuration;
using System.Data; 

namespace DailyTask
{
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.Web.Script.Services.ScriptService()]
    public class AjaxCascadingDropDown : System.Web.Services.WebService
    {
        private static string strconnection = ConfigurationManager.ConnectionStrings["ApplicationServices"].ToString();
       
        SqlConnection concountry = new SqlConnection(strconnection);
        public AjaxCascadingDropDown()
        {

        }
        [WebMethod]
        public CascadingDropDownNameValue[] BindCountryDetails(string knownCategoryValues, string category)
        {
            concountry.Open();
            SqlCommand cmdcountry = new SqlCommand("select * from task6CountryTable", concountry);
            cmdcountry.ExecuteNonQuery();
            SqlDataAdapter dacountry = new SqlDataAdapter(cmdcountry);
            DataSet dscountry = new DataSet();
            dacountry.Fill(dscountry);
            concountry.Close();
            List<CascadingDropDownNameValue> countrydetails = new List<CascadingDropDownNameValue>();
            foreach (DataRow dtrow in dscountry.Tables[0].Rows)
            {
                string CountryID = dtrow["CountryId"].ToString();
                string CountryName = dtrow["CountryName"].ToString();
                countrydetails.Add(new CascadingDropDownNameValue(CountryName, CountryID));
            }

            return countrydetails.ToArray();
        }


        [WebMethod]
        public CascadingDropDownNameValue[] BindStateDetails(string knownCategoryValues, string category)
        {
            int countryID;
            StringDictionary countrydetails = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);
            countryID = Convert.ToInt32(countrydetails["Country"]);
            concountry.Open();
            SqlCommand cmdstate = new SqlCommand("select * from task6StateTable where CountryID=@CountryID", concountry);
            cmdstate.Parameters.AddWithValue("@CountryID", countryID);
            cmdstate.ExecuteNonQuery();
            SqlDataAdapter dastate = new SqlDataAdapter(cmdstate);
            DataSet dsstate = new DataSet();
            dastate.Fill(dsstate);
            concountry.Close();
            List<CascadingDropDownNameValue> statedetails = new List<CascadingDropDownNameValue>();
            foreach (DataRow dtrow in dsstate.Tables[0].Rows)
            {
                string StateID = dtrow["StateID"].ToString();
                string StateName = dtrow["StateName"].ToString();
                statedetails.Add(new CascadingDropDownNameValue(StateName, StateID));
            }
            return statedetails.ToArray();
        }

        [WebMethod]
        public CascadingDropDownNameValue[] BindCityDetails(string knownCategoryValues, string category)
        {
            int stateID;
            StringDictionary statedetails = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);
            stateID = Convert.ToInt32(statedetails["State"]);
            concountry.Open();
            SqlCommand cmdcity = new SqlCommand("select * from task6CityTable where StateID=@StateID", concountry);
            cmdcity.Parameters.AddWithValue("@StateID", stateID);
            cmdcity.ExecuteNonQuery();
            SqlDataAdapter dacity = new SqlDataAdapter(cmdcity);
            DataSet dscity = new DataSet();
            dacity.Fill(dscity);
            concountry.Close();
            List<CascadingDropDownNameValue> citydetails= new List<CascadingDropDownNameValue>();
            foreach (DataRow dtrow in dscity.Tables[0].Rows)
            {
                string CityID = dtrow["CityID"].ToString();
                string CityName = dtrow["CityName"].ToString();
                citydetails.Add(new CascadingDropDownNameValue(CityName, CityID));
            }
            return citydetails.ToArray();
        }
    }
} 

In Your Web.Config paste code like below :-

<connectionStrings>
    <add name="ApplicationServices" connectionString="Data Source=10.1.1.1;Initial Catalog=DailyTaskoskar;Persist Security Info=True;User ID=Username;Password=password" providerName="System.Data.SqlClient"/>
   
  </connectionStrings>