UserControl Docking in VisualStudio

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C#

VS2013

Hi everyone I here this is a my assignment, I want to know how can dock an User Control let me explain what I want,

I designed From1 and UserControl1 and this the Form1, its panel1 and toolStripButton1. button set to call UserControl1 its ok, but i don't know how can I set it to automatically resize with Form1's panel1 width and height. so can anyone help me please

UserControl1

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

namespace XyZ
{
    public partial class UserControl1 : UserControl
    {
        public UserControl1()
        {
            InitializeComponent();
        }

        private void UserControl1_Load(object sender, EventArgs e)
        {

        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }
    }
}

Form1--

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

namespace XyZ
{
    public partial class CustomerInvoice : Form
    {
        public CustomerInvoice()
        {
            InitializeComponent();
        }

        private void toolStripButton1_Click(object sender, EventArgs e)
        {
            panel1.Controls.Clear();
            UserControl1 ust2 = new UserControl1();
            panel1.Controls.Add(ust2);

        }

        private void menuStrip1_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
        {

        }

        private void panel1_Paint(object sender, PaintEventArgs e)
        {

        }
    }
}