Pass Additional Parameter to ASP.Net AJAX AutoCompleteExtender WebMethod using ContextKey in C# and VB.Net

Hi alhakimyyes,

Check the below sample and modify your code accordingly.

Database

For this sample I am making use 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>
<asp:TextBox ID="txtContactsSearch" runat="server" Height="30px" Style="font-size: large;
    font-weight: 700" Width="235px" autocomplete="off"></asp:TextBox>
<cc1:AutoCompleteExtender ServiceMethod="SearchCustomers" MinimumPrefixLength="2"
    CompletionInterval="100" EnableCaching="false" CompletionSetCount="10" TargetControlID="txtContactsSearch"
    UseContextKey="true" ID="AutoCompleteExtender1" runat="server" FirstRowSelected="false">
</cc1:AutoCompleteExtender>
<asp:DropDownList ID="ddlCountries" runat="server" AutoPostBack="true" OnSelectedIndexChanged="OnSelectedIndexChanged">
    <asp:ListItem Text="All Countries" Value="0"></asp:ListItem>
    <asp:ListItem Text="Argentina" Value="Argentina"></asp:ListItem>
    <asp:ListItem Text="Austria" Value="Austria"></asp:ListItem>
    <asp:ListItem Text="Belgium" Value="Belgium"></asp:ListItem>
    <asp:ListItem Text="Brazil" Value="Brazil"></asp:ListItem>
    <asp:ListItem Text="Canada" Value="Canada"></asp:ListItem>
    <asp:ListItem Text="Denmark" Value="Denmark"></asp:ListItem>
    <asp:ListItem Text="Finland" Value="Finland"></asp:ListItem>
    <asp:ListItem Text="France" Value="France"></asp:ListItem>
    <asp:ListItem Text="Germany" Value="Germany"></asp:ListItem>
    <asp:ListItem Text="Ireland" Value="Ireland"></asp:ListItem>
    <asp:ListItem Text="Italy" Value="Italy"></asp:ListItem>
    <asp:ListItem Text="Mexico" Value="Mexico"></asp:ListItem>
    <asp:ListItem Text="Norway" Value="Norway"></asp:ListItem>
    <asp:ListItem Text="Poland" Value="Poland"></asp:ListItem>
    <asp:ListItem Text="Portugal" Value="Portugal"></asp:ListItem>
    <asp:ListItem Text="Spain" Value="Spain"></asp:ListItem>
    <asp:ListItem Text="Sweden" Value="Sweden"></asp:ListItem>
    <asp:ListItem Text="Switzerland" Value="Switzerland"></asp:ListItem>
    <asp:ListItem Text="UK" Value="UK"></asp:ListItem>
    <asp:ListItem Text="USA" Value="USA"></asp:ListItem>
    <asp:ListItem Text="Venezuela" Value="Venezuela"></asp:ListItem>
</asp:DropDownList>

Namespaces

C#

using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Web.Script.Services;
using System.Web.Services;

VB.Net

Imports System.Collections.Generic
Imports System.Configuration
Imports System.Data.SqlClient
Imports System.Web.Script.Services
Imports System.Web.Services

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        AutoCompleteExtender1.ContextKey = ddlCountries.SelectedValue;
    }
}

[ScriptMethod()]
[WebMethod]
public static List<string> SearchCustomers(string prefixText, int count, string contextKey)
{
    using (SqlConnection conn = new SqlConnection())
    {
        conn.ConnectionString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlCommand cmd = new SqlCommand())
        {
            string cmdText = "select CustomerID,ContactName from Customers where ContactName like '%'+ @SearchText + '%'";
            cmd.Parameters.AddWithValue("@SearchText", prefixText);
            if (contextKey != "0")
            {
                cmdText += " and Country = @Country";
                cmd.Parameters.AddWithValue("@Country", contextKey);
            }
            cmd.CommandText = cmdText;
            cmd.Connection = conn;
            conn.Open();
            List<string> customers = new List<string>();
            using (SqlDataReader sdr = cmd.ExecuteReader())
            {
                while (sdr.Read())
                {
                    customers.Add(string.Format("{0}-{1}", sdr["ContactName"], sdr["CustomerID"]));
                }
            }
            conn.Close();
            return customers;
        }
    }
}

protected void OnSelectedIndexChanged(object sender, EventArgs e)
{
    AutoCompleteExtender1.ContextKey = ddlCountries.SelectedValue;
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not IsPostBack Then
        AutoCompleteExtender1.ContextKey = ddlCountries.SelectedValue
    End If
End Sub

<ScriptMethod(), _
WebMethod()> _
Public Shared Function SearchCustomers(ByVal prefixText As String, ByVal count As Integer, ByVal contextKey As String) As List(Of String)
    Using conn As SqlConnection = New SqlConnection()
        conn.ConnectionString = ConfigurationManager.ConnectionStrings("constr").ConnectionString
        Using cmd As SqlCommand = New SqlCommand()
            Dim cmdText As String = "select CustomerID,ContactName from Customers where ContactName like '%'+ @SearchText + '%'"
            cmd.Parameters.AddWithValue("@SearchText", prefixText)
            If contextKey <> "0" Then
                cmdText += " and Country = @Country"
                cmd.Parameters.AddWithValue("@Country", contextKey)
            End If

            cmd.CommandText = cmdText
            cmd.Connection = conn
            conn.Open()
            Dim customers As List(Of String) = New List(Of String)()
            Using sdr As SqlDataReader = cmd.ExecuteReader()
                While sdr.Read()
                    customers.Add(String.Format("{0}-{1}", sdr("ContactName"), sdr("CustomerID")))
                End While
            End Using
            conn.Close()

            Return customers
        End Using
    End Using
End Function

Protected Sub OnSelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
    AutoCompleteExtender1.ContextKey = ddlCountries.SelectedValue
End Sub

Screenshot