Show hide TextBox based on database records while typing in ASP.Net using PageMethod

Hi micah,

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

<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true">
</asp:ScriptManager>
<div class="container">
    <asp:TextBox ID="txtName" runat="server" CssClass="form-control" placeholder="Insert Name"
        onkeyup="ShowHidePriceTextBox()"></asp:TextBox>
    <br />
    <asp:TextBox ID="txtPrice" runat="server" CssClass="form-control" placeholder="Insert Price"
        Style="display: none;"></asp:TextBox>
</div>

<script type="text/javascript">
    function ShowHidePriceTextBox() {
        PageMethods.CheckName(document.getElementById("<%=txtName.ClientID%>").value, OnSuccess);
    }
    function OnSuccess(response) {
        document.getElementById("<%=txtPrice.ClientID%>").style.display = response;
    }
</script>

Namespaces

C#

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

VB.Net

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

Code

C#

[WebMethod]
public static string CheckName(string name)
{
    string display = "";
    string conString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    string query = "SELECT COUNT(ProductName) FROM Products WHERE ProductName = @Name";
    using (SqlConnection con = new SqlConnection(conString))
    {
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandText = query;
        cmd.Parameters.AddWithValue("@Name", name);
        con.Open();
        display = Convert.ToInt32(cmd.ExecuteScalar()) > 0 ? "block" : "none";
        con.Close();
    }

    return display;
}

VB.Net

<WebMethod>
Public Shared Function CheckName(ByVal name As String) As String
    Dim display As String = ""
    Dim conString As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Dim query As String = "SELECT COUNT(ProductName) FROM Products WHERE ProductName = @Name"
    Using con As SqlConnection = New SqlConnection(conString)
        Dim cmd As SqlCommand = New SqlCommand()
        cmd.Connection = con
        cmd.CommandText = query
        cmd.Parameters.AddWithValue("@Name", name)
        con.Open()
        display = If(Convert.ToInt32(cmd.ExecuteScalar()) > 0, "block", "none")
        con.Close()
    End Using

    Return display
End Function

Screenshot