Access Div tag in Page from Masterpage codebehind - webforms

Question

I need access div in a page.
page.aspx
<asp:Content ID="Content" ContentPlaceHolderID="ContentPlaceHolderBody1" runat="server">
<div class="table-responsive">
<div class="card card-authentication1 mx-auto my-5" id="div_Payment" runat="server"></div>
</div
</asp:Content>
masterpage
protected void Admin_Load(object sender, EventArgs e)
{
HtmlControl control = (HtmlControl)Page.FindControl("ContentPlaceHolderBody1").FindControl("div_Payment");
HtmlControl control = (HtmlControl)Master.FindControl("ContentPlaceHolderBody1").FindControl("div_Payment");
control.Style.Add("display", "none");
}
no luck.

Answer 1

This should work:
Markup:
<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
<asp:Label ID="Label1" runat="server" Text="This is fun"></asp:Label>
<div class="table-responsive">
<div class="card card-authentication1 mx-auto my-5" id="div_Payment" runat="server">xxxx</div>
</div>
</asp:Content>
code behind on master page:
System.Web.UI.WebControls.Label MyLabel1 =
(System.Web.UI.WebControls.Label)MainContent.FindControl("Label1");
Debug.Print("Value of Lable 1 on child page = " + MyLabel1.Text);
HtmlGenericControl MyDiv = (HtmlGenericControl)MainContent.FindControl("div_Payment");
Debug.Print("Inner text = " + MyDiv.InnerText);
so, you don't have to "find" the first "content" control - that will exist.
(you could, but it not required).

Answer 2

I found it
HtmlControl MyDiv = (HtmlControl)Page
.Master
.FindControl("ContentPlaceHolderBody1")
.FindControl("Panel1");