MDI vs. SDI

MDI and SDI are interface designs for handling documents within a single application. MDI stands for “Multiple Document Interface” while SDI stands for “Single Document Interface”. Both are different from each other in many aspects. One document per window is enforced in SDI while child windows per document are allowed in MDI. SDI contains one window only at a time but MDI contain multiple document at a time appeared as child window. MDI is a container control while SDI is not container control. MDI supports many interfaces means we can handle many applications at a time according to user’s requirement. But SDI supports one interface means you can handle only one application at a time.

What is MDI?

MDI stands for Multiple Document Interface.  It is an interface design for handling documents within a single application. When application consists of an MDI parent form containing all other window consisted of the app, then MDI interface can be used. Switch focus to a specific document can be easily handled in MDI. For maximizing all documents, parent window is maximized by MDI.

What is SDI?

SDI stands for Single Document Interface. It is an interface design for handling documents within a single application. SDI exists independently from others and thus is a stand-alone window. SDI supports one interface means you can handle only one application at a time. For grouping, SDI uses special window managers.

Key Differences between MDI and SDI

1. MDI stands for “Multiple Document Interface” while SDI stands for “Single Document Interface”.
2. One document per window is enforced in SDI while child windows per document are allowed in MDI.
3. MDI is a container control while SDI is not container control.
4. SDI contains one window only at a time but MDI contains multiple documents at a time appeared as child window.
5. MDI supports many interfaces means we can handle many applications at a time according to user’s requirement. But SDI supports one interface means you can handle only one application at a time.
6. For switching between documents MDI uses special interface inside the parent window while SDI uses Task Manager for that.
7. In MDI grouping is implemented naturally but in SDI grouping is possible through special window managers.
8. For maximizing all documents, parent window is maximized by MDI but in case of SDI, it is implemented through special code or window manager.
9. Switch focus to the specific document can be easily handled while in MDI but it is difficult to implement in SDI.

Video Explanation