Delphi stores forms and their components in form (.dfm in VCL applications ) files. A form file stores the properties of a form and its components. When Delphi developers add the components you write to their forms, your components must have the ability to write their properties to the form file when saved. Similarly, when loaded into Delphi or executed as part of an application, the components must restore themselves from the form file. 

Most of the time you will not need to do anything to make your components work with form files because the ability to store a representation and load from it are part of the inherited behavior of components. Sometimes, however, you might want to alter the way a component stores itself or the way it initializes when loaded; so you should understand the underlying mechanism. 

These are the aspects of property storage you need to understand:

• Using the store-and-load mechanism
• Specifying default values
• Determining what to store
• Initializing after loading
• Storing and loading unpublished properties