C# MDI Form

A Multiple Document Interface (MDI) programs can display multiple child windows inside them. This is in contrast to single document interface (SDI) applications, which can manipulate only one document at a time. Visual Studio Environment is an example of Multiple Document Interface (MDI) and notepad is an example of an SDI application. MDI applications often have a Window menu item with submenus for switching between windows or documents.

Any windows can become an MDI parent, if you set the IsMdiContainer property to True.

  IsMdiContainer = true;

The following C# program shows a MDI form with two child forms. Create a new C# project, then you will get a default form Form1 . Then add two mnore forms in the project (Form2 , Form 3) . Create a Menu on your form and call these two forms on menu click event. Click here to see how to create a Menu on your form How to Menu Control C#.

using System;
using System.Drawing;
using System.Windows.Forms;

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

        private void Form1_Load(object sender, EventArgs e)
        {
            IsMdiContainer = true;
        }

        private void menu1ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Form2 frm2 = new Form2();
            frm2.Show();
            frm2.MdiParent = this;
        }

        private void menu2ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Form3 frm3 = new Form3();
            frm3.Show();
            frm3.MdiParent = this;
        }
    }
}