how to open a web page as a child form in mdi fom

It is not as easy as you want it to be. Look for articles in this web site; there are a few at least that are about the WebBrowser control. I suggest creating a MDI Child form using the designer and then adding a WebBrowser control to it, but if you need more details, please read the articles first.

 

Hey, Josip; note that this question is quite old.

You didin't form your question well. But if I understnad that should be like this:

this.IsMdiContainer = true;

            Form childForm = new Form();

            WebBrowser wb = new WebBrowser();
            childForm.MdiParent = this;
            childForm.Size = new Size(657, 482);
            childForm.Controls.Add(wb);
            wb.Dock = DockStyle.Fill;

            //here you enter page that you want to show
            wb.Navigate("YourPage");
           
            childForm.Show();