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 way to clear all the controls on a form back to their defaults (e.g., clear textboxes, uncheck checkboxes).

How would you go about this?

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

I know its an old question but just my 2 cents in. This is a helper class I use for form clearing.

using System;
using System.Windows.Forms;

namespace FormClearing
{
    class Helper
    {
        public static void ClearFormControls(Form form)
        {
            foreach (Control control in form.Controls)
            {
                if (control is TextBox)
                {
                    TextBox txtbox = (TextBox)control;
                    txtbox.Text = string.Empty;
                }
                else if(control is CheckBox)
                {
                    CheckBox chkbox = (CheckBox)control;
                    chkbox.Checked = false;
                }
                else if (control is RadioButton)
                {
                    RadioButton rdbtn = (RadioButton)control;
                    rdbtn.Checked = false;
                }
                else if (control is DateTimePicker)
                {
                    DateTimePicker dtp = (DateTimePicker)control;
                    dtp.Value = DateTime.Now;
                }
            }
        }
    }
}

And I call the method from any form like this passing a form object as a parameter.

Helper.ClearFormControls(this);

You can extend it for other types of controls. You just have to cast it.