<p>I am having a number of panels in my page in which I am collecting user information and saving the page details. The page panel has textbox, dropdown list, listbox.</p>

<p>When I need to come to this page. I need to show the Page if these controls have any values. How to do this?</p>

It boils down to enumerating all the controls in the control hierarchy:
```
```
IEnumerable<Control> EnumerateControlsRecursive(Control parent)
    {
        foreach (Control child in parent.Controls)
        {
            yield return child;
            foreach (Control descendant in EnumerateControlsRecursive(child))
                yield return descendant;
        }
    }
```
```
You can use it like this:
```
```
foreach (Control c in EnumerateControlsRecursive(Page))
        {
            if(c is TextBox)
            {
                // do something useful
            }
        }
```
```