How to get control(s) from TabPage in C#?

Question

I have few TabPages and each contains rich text box. How can I access richtechbox on a selected tab?

TabPage selectedTab = tabControl.SelectedTab;
RichTextBox selectedRtb = selectedTab.Controls.Find("rtb", true).First() as RichTextBox;

This is what I have tried but no luck.

Added:

This is how tabpage is added with richtextbox control

TabPage newTab = new TabPage(name);
RichTextBox rtb = new RichTextBox();
rtb.Dock = DockStyle.Fill;
rtb.BorderStyle = BorderStyle.None;
rtb.Text = file.Data;
newTab.Controls.Add(rtb);
tabControl.TabPages.Add(newTab);
tabControl.SelectedTab = newTab;

Answer 1

If this is WinForms, it would just be:

if (selectedTab.Controls.ContainsKey("rtb"))
  RichTextBox selectedRtb = (RichTextBox)selectedTab.Controls["rtb"];

if rtb is the name of the RichTextBox control.

When creating your control, add the name to it:

RichTextBox rtb = new RichTextBox();
rtb.Name = "rtb";