If you only want the immediate children, use
...
var children = control.Controls.OfType<Control>();
...
If you want all controls from the hierarchy (ie, everything in the tree under a certain control), use a pretty simple data-recursive method:
private IEnumerable<Control> GetControlHierarchy(Control root)
{
var queue = new Queue<Control>();
queue.Enqueue(root);
do
{
var control = queue.Dequeue();
yield return control;
foreach (var child in control.Controls.OfType<Control>())
queue.Enqueue(child);
} while (queue.Count > 0);
}
Then, you might use something like this in a form:
private void button1_Click(object sender, EventArgs e)
{
/// get all of the controls in the form's hierarchy in an IEnumerable<>
foreach (var control in GetControlHierarchy(this))
{
/// do something with this control
}
}