MDI (Multi Document Interface) Form is form that can hold multi forms inside it.

Examples -

MDI - Excel
SDI - Notepad

MDI Form Contain the Multiple MDICHILD form and Dialog form
But Simple for do not able to contain any form in it.

MDI forms are certainly helpful for embedding other forms. Something that a lot of people don't know, is that you can make any window that has an hWnd, the child of another form with a simple API call. So, essentially, even top level windows CAN be MDI, but in practice, this is rude.

Hi Frns

hi can somebosy tell me how to post the question which i want to ask, Cz i m new to the site

click on "Start New thread", a yellow one on top of posts.

hey, i m not able to see,,,I just see
Thread Tools Rate Thread Display Modes
on top of posts

no no ... not in this thread but in vb 6 forum. go to "Software Development" and put your cursor on there. pop menu will go down, select for vb 4/5/6. in this section you will see "Start New Thread", a yellow one on top of post. if u want to post in other section do the same think. or you can click "new thread" on this thread, see in above of post box.