An object reference is required for the non-static field, method, or property System.Web.UI.Page.Master.get

Hi,

I'm using jQuery and setInterval method in my asp.net web application.

I call the webservice every 5 seconds in order to check for DB changes. When i see a change, i want to change the photo of the linkButton that located on the master page, but i can to that due to static constrains.

An object reference is required for the non-static field, method, or property 'System.Web.UI.Page.Master.get'

my c# code is:

[WebMethod()]
public static bool checkDBChange(string userId)
{
    DBConnection dbConnection = new DBConnection();
    if (dbConnection.isChanged(userId))
    {
        ((Site1)Master).SetImageUrl = "~/Icons/a.ico";
    }
    return false;
}

The SetImageUrl is a setter in my master page that sets the new url to the linkButton.

Any idea how i can implement it?