多项选择题

A.Add the following line of code to the TestUserControl.ascx.cs code-behind file. public string CityName { get { return "New York"; } } 
B.Add the following line of code to the TestUserControl.ascx.cs code-behind file. protected readonly string CityName = "New York"; 
C.Add the following code segment to the TestPage.aspx.cs code-behind file. protected void Page_Load(object sender, EventArgs e) { string s = testControl.CityName; } 
D.Add the following code segment to the TestPage.aspx.cs code-behind file. protected void Page_Load(object sender, EventArgs e) { string s = testControl.Attributes["CityName"]; }