Read (Get) AppSettings Key Value in ASPX page from Web.Config file in ASP.Net

Here Mudassar Ahmed Khan has explained with an example, how to read (get) key values of AppSettings section in ASPX page from ASP.Net Web.Config file using C# and VB.Net. In ASP.Net Web Applications, one has to reference the System.Configuration Assembly in order to read AppSetting values from the Web.Config file. In ASPX Page, the AppSetting values will be read from Web.Config file using Server-Side code blocks (<% %>).