Find Control in Page with Master Page


Master Page
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <asp:ContentPlaceHolder ID="head" runat="server">
    </asp:ContentPlaceHolder>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Label ID="lbloutcp" runat="server" Text="Basic"></asp:Label>
        <br />
        <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
        </asp:ContentPlaceHolder>
    </div>
    </form>
</body>
</html>

Page with Master:
.aspx
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
    <br />
    <asp:TextBox ID="TextBox1" runat="server">
    </asp:TextBox><br />
    <asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
    <br />
    <div>
        <asp:Label ID="lblincp" runat="server" Text="Basic"></asp:Label>
    </div>
</asp:Content>

.aspx.cs:

protected void Button1_Click(object sender, EventArgs e)
        {
            string text = TextBox1.Text;
            Label lbl = (Label)Master.FindControl("lbloutcp");
            lbl.Visible = true;
            lbl.Text = text + " Master Page Place holder";

            ContentPlaceHolder cph = (ContentPlaceHolder)Master.FindControl("ContentPlaceHolder1");
            Label lbl2 = (Label)cph.FindControl("lblincp");
            lbl2.Visible = true;
            lbl2.Text = text + " In Content Place holder";
        }