VS 2012 - Set Text Of Master Page Label From Content Page

I have a label in the master page

<asp:Label ID="lblLogName" runat="server">Test</asp:Label>

I have created a public property in the master page

Public Property LoginName As String
Get
Return lblLogName.Text
End Get

Set(ByVal value As String)
lblLogName.Text = value
End Set
End Property

I have written a page directive in the content page

<%@ MasterType VirtualPath="~/Site.Master" %>

I am trying to set the value of the label in the master page by

Master.LoginName = LabelName.Text

But the value in the master page label is not changed.