Hi RichardSa,

Referring the below articles i have created the sample.

Simple Blog Tutorial with example in ASP.Net using C# and VB.Net

Fetch multiple values as Key Value pair in ASP.Net AJAX AutoCompleteExtender

Global.asax

static void RegisterRoutes(RouteCollection routes)
{
    routes.MapPageRoute("Default", "Default", "~/Default.aspx");
    routes.MapPageRoute("DisplayBlog", "Blogs/{BlogId}/{Slug}", "~/DisplayBlog.aspx");
}

HTML

Default

<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true"></asp:ScriptManager>
<asp:TextBox ID="txtBlog" runat="server"></asp:TextBox>
<cc1:AutoCompleteExtender ID="ae1" runat="server" ServiceMethod="SearchBlogs" ServicePath="Default.aspx"
    MinimumPrefixLength="2" CompletionInterval="100" EnableCaching="false" CompletionSetCount="10"
    TargetControlID="txtBlog" FirstRowSelected="false" OnClientItemSelected="OnClientItemSelected">
</cc1:AutoCompleteExtender>
<script type="text/javascript">
    function OnClientItemSelected(sender, args) {
        var title = args.get_text().replace(".", "");
        var blogId = args.get_value();
        window.location.href = "/Blogs/" + blogId + "/" + encodeURI(title);
    }
</script>

DisplayBlog

<h2><asp:Label ID="lblTitle" runat="server" /></h2>
<hr />
<asp:Label ID="lblBody" runat="server" />

Namespaces

using System.Data;
using System.Configuration;
using System.Data.SqlClient;

Code

Default

[WebMethod]
public static List<string> SearchBlogs(string prefixText, int count)
{
    List<string> blogs = new List<string>();
    using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand())
        {
            cmd.CommandText = "SELECT [BlogId], [Title], REPLACE([Title], ' ', '-') [SLUG], [Body] FROM [Blogs] WHERE [Title] LIKE @SearchText + '%'";
            cmd.Parameters.AddWithValue("@SearchText", prefixText);
            cmd.Connection = conn;
            conn.Open();
            using (SqlDataReader sdr = cmd.ExecuteReader())
            {
                while (sdr.Read())
                {
                    blogs.Add(AjaxControlToolkit.AutoCompleteExtender.CreateAutoCompleteItem(
                        sdr["Title"].ToString(),
                        sdr["BlogId"].ToString()));
                }
            }
            conn.Close();

            return blogs;
        }
    }
}

DisplayBlog

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        if (this.Page.RouteData.Values.Count > 0)
        {
            string articleId = this.Page.RouteData.Values["BlogId"].ToString();
            string articleTitle = this.Page.RouteData.Values["Slug"].ToString();
            this.PopulateBlog(articleId);
        }
    }
}

private void PopulateBlog(string blogId)
{
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT [Title], [Body] FROM [Blogs] WHERE [BlogId] = @BlogId", con))
        {
            cmd.Parameters.AddWithValue("@BlogId", blogId);
            using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
            {
                using (DataTable dt = new DataTable())
                {
                    sda.Fill(dt);
                    lblTitle.Text = dt.Rows[0]["Title"].ToString();
                    lblBody.Text = dt.Rows[0]["Body"].ToString();
                }
            }
        }
    }
}

Screenshot