jQuery AJAX: Check Record Exists or Not using C# VB.Net and WebMethod

Hi RahurkarP,

Check this example. Now please take its reference and correct your code.

Database

For this example I have used of Northwind database that you can download using the link given below.

Download Northwind Database

HTML

Page1.aspx

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
    $(function () {
        $('[id*=txtFname]').on('change', function () {
            var findName = $(this).val();
            if (findName != "") {
                window.location.href = "Default.aspx?findName=" + findName;
            }
        });
    });
</script>
<table style="width: 40%;">
    <tr>
        <td>
            First Name :
        </td>
        <td>
            <input type="text" id="txtFname" />
        </td>
    </tr>
</table>

Default.aspx

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
    $(document).ready(function () {
        var name = window.location.search.split('=')[1];
        if (name != '') {
            $.ajax({
                type: "POST",
                url: "Default.aspx/IsExist",
                contentType: "application/json;charset=utf-8",
                data: '{findName:"' + name + '"}',
                dataType: "json",
                success: function (data) {
                    if (data.d == "NotExist") {
                        $('[id*=GrdEmployee]').hide();
                    }
                    else {
                        $('[id*=GrdEmployee]').show();
                    }
                },
                error: function (result) {
                    alert(result.responsetext);
                }
            });
        }
    });
</script>
<asp:GridView runat="server" ID="GrdEmployee" EmptyDataText="No record" />

Namespaces

C#

using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Web.Services;

VB.Net

Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.Services

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        if (Request.QueryString["findName"] != null)
        {
            findData(Request.QueryString["findName"].ToString());
        }
    }
}

private void findData(string findName)
{
    try
    {
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings[1].ConnectionString);
        conn.Open();
        string query = "select FirstName,LastName,City,Country from Employees WHERE FirstName LIKE  @findName + '%'";
        SqlCommand cmd = new SqlCommand(query, conn);
        cmd.Parameters.AddWithValue("@findName", findName);
        SqlDataReader reader = cmd.ExecuteReader();
        DataTable dt = new DataTable();
        dt.Load(reader);
        GrdEmployee.DataSource = dt;
        GrdEmployee.DataBind();
    }
    catch (Exception ex)
    {
    }
}

[WebMethod]
public static string IsExist(string findName)
{
    string isRecordExist = "";
    try
    {
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings[1].ConnectionString);
        conn.Open();
        string query = "select Count(*) from Employees WHERE FirstName LIKE @findName + '%'";
        SqlCommand cmd = new SqlCommand(query, conn);
        cmd.Parameters.AddWithValue("@findName", findName);
        int i = Convert.ToInt32(cmd.ExecuteScalar());
        isRecordExist = i > 0 ? "Exist" : "NotExist";
    }
    catch (Exception ex)
    {
    }
    return isRecordExist;
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not IsPostBack Then

        If Request.QueryString("findName") IsNot Nothing Then
            findData(Request.QueryString("findName").ToString())
        End If
    End If
End Sub

Private Sub findData(ByVal findName As String)
    Try
        Dim conn As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings(1).ConnectionString)
        conn.Open()
        Dim query As String = "select FirstName,LastName,City,Country from Employees WHERE FirstName LIKE  @findName + '%'"
        Dim cmd As SqlCommand = New SqlCommand(query, conn)
        cmd.Parameters.AddWithValue("@findName", findName)
        Dim reader As SqlDataReader = cmd.ExecuteReader()
        Dim dt As DataTable = New DataTable()
        dt.Load(reader)
        GrdEmployee.DataSource = dt
        GrdEmployee.DataBind()
    Catch ex As Exception
    End Try
End Sub

<WebMethod()>
Public Shared Function IsExist(ByVal findName As String) As String
    Dim isRecordExist As String = ""
    Try
        Dim conn As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings(1).ConnectionString)
        conn.Open()
        Dim query As String = "select Count(*) from Employees WHERE FirstName LIKE @findName + '%'"
        Dim cmd As SqlCommand = New SqlCommand(query, conn)
        cmd.Parameters.AddWithValue("@findName", findName)
        Dim i As Integer = Convert.ToInt32(cmd.ExecuteScalar())
        isRecordExist = If(i > 0, "Exist", "NotExist")
    Catch ex As Exception
    End Try
    Return isRecordExist
End Function

Screenshot