The visual component library)

Form-based programming (Form-based) This concept was first promoted by Microsoft Visual Basic. But unlike Visual Basic, Delphi is derived from Pascal.Programming LanguageThis new language is called Object Pascal, which introduces OOP to Pascal. Delphi and Object Pascal indicate the combination of object-oriented programming and form-based programming. In addition, Delphi can generate separate executable files. For actualProgramIt is a program that does not need to run a stage DLL. It is a program that is compiled rather than interpreted. It runs dozens of times faster than the Visual BASIC program, this is very influential in the field of programming.

Delphi introduces not only Object Pascal, but also visual component library. As mentioned earlier, VCL is an application architecture for Object Pascal windows programming, the most notable feature of VCL is that it is designed as a visual component mode with properties, methods, and events.

Attribute,MethodAndEventConstitute the public interface of Components in VCL (some component users can see ).

In the subsequent sections, we will explain the three elements of attributes, methods, and events.