Reset Code in C#

Example : How to Clean/Clear/Reset/Cancel the C# Elements or Controls data.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

            CmbNationality.Items.Add("Select One");
            CmbNationality.Items.Add("India");
            CmbNationality.Items.Add("USA");
            CmbNationality.Items.Add("SriLanka");
            CmbNationality.Items.Add("Bhutan");
            CmbNationality.Items.Add("Nepal");
            CmbNationality.Items.Add("Other");
            
            // No item selected initially
            //CmbNationality.SelectedIndex = -1;

            // First item selected initially
            CmbNationality.SelectedIndex = 0;

            Clear();
        }

        private void UrBtnExit_Click(object sender, EventArgs e)
        {
            this.Close(); 
        }

        private void Clear()
        {
            TxtSlno.Text = "";

            TxtUserId.Clear();      //TxtUserId.Text = "";

            TxtAddress.Clear();

            TxtPass.Clear();

            TxtCPass.Clear();

            TxtMob.Text = "";

            DtpDob.Value = DateTime.Today;

            RdbMale.Checked = false;
            RdbFemale.Checked = false;
            RdbOther.Checked = false;

            ChkNonMatric.Checked = false;
            ChkMatric.Checked = false;
            ChkItermediate.Checked = false;
            ChkGradPostG.Checked = false;

            // First item selected initially
            CmbNationality.SelectedIndex = 0;

            // No item selected initially
            //CmbNationality.SelectedIndex = -1;

            // to remove typed text
            //CmbNationality.Text = "";

            RtbRemarks.Text = "N/A";
            //RtbRemarks.Text = ""; //Rich text box
            //RtbRemarks.Clear();

            //listBox1.ClearSelected();            
            //listBox1.Items.Clear(); 

            //pictureBox1.Image = null;

            //label1.Text = ""; 

            TxtSlno.Focus();
        }
        
        private void UrBtnClear_Click(object sender, EventArgs e)
        {

            Clear();
        }       
        
    }
}