C# - Search Database Table For Value And Put It In A Datatable?

I have a textbox and a search button i trying to search file names in a database table and display them in a datatable...

private void GetSearchResults(string machineID, string searchFileName)
{
DataTable dt = new DataTable();
SqlConnection connection = new SqlConnection();
connection.ConnectionString = ConfigurationManager.ConnectionStrings["SumooHAgentDBConnectionString"].ConnectionString;
connection.Open();
SqlCommand sqlCmd = new SqlCommand("SELECT FileID, BuFileName FROM BackedUpFiles WHERE BuFileName Like '%@searchFileName%' AND MachineID=@machineID", connection);
SqlDataAdapter sqlDa = new SqlDataAdapter(sqlCmd);
sqlCmd.Parameters.AddWithValue("@machineID", machineID);
sqlCmd.Parameters.AddWithValue("@searchFileName", searchFileName);
sqlDa.Fill(dt);
}

everything is working fine except that the searchFileName is not working in the query...

I tried putting just a value to check like

SELECT FileID, BuFileName FROM BackedUpFiles WHERE BuFileName Like '%b%' AND MachineID=@machineID