sqldependency in asp.net

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C#

ASP.NET

SQL

Hello
I got stuck in some code. I'm working now on the return of the SQL database (note that - no SQL SERVER MANAGEMENT STUDIO) built into the MDF file VISUAL STUDIO The code looks like this:

using (SqlCommand cmd = new SqlCommand(query, MyConnection))
{
cmd.Notification = null;
DataTable dt = new DataTable();

SqlDependency dependency = new SqlDependency(cmd);
if (MyConnection.State == ConnectionState.Closed)
MyConnection.Open();


var rdr = cmd.ExecuteReader();
dt.Load(rdr);
if (dt.Rows.Count > 0)
{
name = dt.Rows[0]["ProdName"].ToString();
price = int.Parse(dt.Rows[0]["Price"].ToString());
image = dt.Rows[0]["Images"].ToString();

}

dependency.OnChange += new OnChangeEventHandler

(dependency_OnChange);

..........
But for some reason it does not work and appears to me an error that says:
"A database with the same name exists, or specified file cannot be opened, or it is located on UNC share"

I also updated the file WEB.CONFIG

caching
sqlCacheDependency pollTime="500" enabled="true"

add name="Dataprod" connectionStringName="ConnectionString"
databases
sqlCacheDependency
caching


........

And it does not work

Thanks