What is the best way to clear all controls on a form C#?

Question

I do remember seeing someone ask something along these lines a while ago but I did a search and couldn\'t find anything.

I\'m trying to come up with the cleanest wa

Answer 1

What I have come up with so far is something like this:

public static class extenstions
{
    private static Dictionary<Type, Action<Control>> controldefaults = new Dictionary<Type, Action<Control>>() { 
            {typeof(TextBox), c => ((TextBox)c).Clear()},
            {typeof(CheckBox), c => ((CheckBox)c).Checked = false},
            {typeof(ListBox), c => ((ListBox)c).Items.Clear()},
            {typeof(RadioButton), c => ((RadioButton)c).Checked = false},
            {typeof(GroupBox), c => ((GroupBox)c).Controls.ClearControls()},
            {typeof(Panel), c => ((Panel)c).Controls.ClearControls()}
    };

    private static void FindAndInvoke(Type type, Control control) 
    {
        if (controldefaults.ContainsKey(type)) {
            controldefaults[type].Invoke(control);
        }
    }

    public static void ClearControls(this Control.ControlCollection controls)
    {
        foreach (Control control in controls)
        {
             FindAndInvoke(control.GetType(), control);
        }
    }

    public static void ClearControls<T>(this Control.ControlCollection controls) where T : class 
    {
        if (!controldefaults.ContainsKey(typeof(T))) return;

        foreach (Control control in controls)
        {
           if (control.GetType().Equals(typeof(T)))
           {
               FindAndInvoke(typeof(T), control);
           }
        }    

    }

}

Now you can just call the extension method ClearControls like this:

 private void button1_Click(object sender, EventArgs e)
    {
        this.Controls.ClearControls();
    }

EDIT: I have just added a generic ClearControls method that will clear all the controls of that type, which can be called like this:

this.Controls.ClearControls<TextBox>();

At the moment it will only handle top level controls and won't dig down through groupboxes and panels.

Answer 2

Below are methods I use to clear text from a type of control that implements ITextBox.

I noticed in the example default boolean values are set. I'm sure you can modify it to set default values of boolean components.

Pass the Clear method a control type (TextBox, Label... etc) and a control collection, and it will clear all text from controls that implement ITextBox.

Something like this:

//Clears the textboxes
WebControlUtilities.ClearControls<TextBox>(myPanel.Controls);

The Clear method is meant for a Page or Masterpage. The control collection type may vary. ie. Form, ContentPlaceHolder.. etc

        /// <summary>
    /// Clears Text from Controls...ie TextBox, Label, anything that implements ITextBox
    /// </summary>
    /// <typeparam name="T">Collection Type, ie. ContentPlaceHolder..</typeparam>
    /// <typeparam name="C">ie TextBox, Label, anything that implements ITextBox</typeparam>
    /// <param name="controls"></param>
    public static void Clear<T, C>(ControlCollection controls)
        where C : ITextControl
        where T : Control
    {
        IEnumerable<T> placeHolders = controls.OfType<T>();
        List<T> holders = placeHolders.ToList();

        foreach (T holder in holders)
        {
            IEnumerable<C> enumBoxes = holder.Controls.OfType<C>();
            List<C> boxes = enumBoxes.ToList();

            foreach (C box in boxes)
            {
                box.Text = string.Empty;
            }
        }
    }

    /// <summary>
    /// Clears the text from control.
    /// </summary>
    /// <typeparam name="C"></typeparam>
    /// <param name="controls">The controls.</param>
    public static void ClearControls<C>(ControlCollection controls) where C : ITextControl
    {
        IEnumerable<C> enumBoxes = controls.OfType<C>();
        List<C> boxes = enumBoxes.ToList();

        foreach (C box in boxes)
        {
            box.Text = string.Empty;
        }
    }