Loop through all controls of a Form, even those in GroupBoxes

Question

I\'d like to add an event to all TextBoxes on my Form:

foreach (Control C in this.Controls)
{
    if (C.GetType() == typeof(System.Windows.Forms         


        

Answer 1

A few simple, general purpose tools make this problem very straightforward. We can create a simple method that will traverse an entire control's tree, returning a sequence of all of it's children, all of their children, and so on, covering all controls, not just to a fixed depth. We could use recursion, but by avoiding recursion it will perform better.

public static IEnumerable GetAllChildren(this Control root)
{
    var stack = new Stack();
    stack.Push(root);

    while (stack.Any())
    {
        var next = stack.Pop();
        foreach (Control child in next.Controls)
            stack.Push(child);
        yield return next;
    }
}

Using this we can get all of the children, filter out those of the type we need, and then attach the handler very easily:

foreach(var textbox in GetAllChildren().OfType())
    textbox.TextChanged += C_TextChanged;