Question

I am trying to find an elegant way to get controls on a Windows Forms form by name. For example:

MyForm.GetControl "MyTextBox"

...

But this has to make sure it goes through all the controls recursively.

What’s the most elegant way to implement this using LINQ?

Answer 1

LINQ isn’t necessarily best-suited to unknown-depth recursion; just use regular code…

public static Control FindControl(this Control root, string name) {
    if(root == null) throw new ArgumentNullException("root");
    foreach(Control child in root.Controls) {
        if(child.Name == name) return child;
        Control found = FindControl(child, name);
        if(found != null) return found;
    }
    return null;
}

with:

Control c = myForm.GetControl("MyTextBox");

Or if you don’t like the recursion above:

public Control FindControl(Control root, string name) {
    if (root == null) throw new ArgumentNullException("root");
    var stack = new Stack<Control>();
    stack.Push(root);
    while (stack.Count > 0) {
        Control item = stack.Pop();
        if (item.Name == name) return item;
        foreach (Control child in item.Controls) {
            stack.Push(child);
        }
    }
    return null;
}