How to use form controls in C#

using System;

using System.Windows.Forms;

namespace Controls_Of_Forms

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

private void btnclose_Click(object sender, EventArgs e)

{

DialogResult = MessageBox.Show("Do you want to close this window?", "Controls Of Forms", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);

if(DialogResult == DialogResult.No)

{

return;

}

this.Close();

}

private void btnmximize_Click(object sender, EventArgs e)

{

if (this.WindowState == FormWindowState.Maximized) this.WindowState = FormWindowState.Normal;

else if (this.WindowState == FormWindowState.Normal) this.WindowState = FormWindowState.Maximized;

}

private void btnminimize_Click(object sender, EventArgs e)

{

this.WindowState = FormWindowState.Minimized;

}

}

}