Delphi procedures to make the main points

One, why Choose Delphi

Before you start any project, you will always encounter the problem of choosing a development tool. All kinds of tools have their own characteristics, each has its own pros and cons. Choose Delphi, each person has the reason, some people are heard good, run to see, some people are forced. When will people be forced to use Delphi? For me,

1 I do not want to use ODBC in a small project, I found BDE efficiency is very good, so very happy.

2 I hate OCX, VBX, a lot of other people's things into the user's machine, so I have no sense of achievement.

3 I have very little opportunity to do cview/cdocument form of the program, and MFC for other support is surprisingly poor.

4 I like Pascal very much, I knock begin....end not necessarily than knock {...} How much slower.

(5) C and C + + online resources are too few, can only occasionally find some snippet

Ii. some basic concepts

A. Object-oriented concept simply put, Pascal's original record type, plus procedure and function, became class. So, a class is essentially a variable, Implementation defines the details of the variable, interface is the definition of the variable, telling the compiler where to find specific code when someone else references me. One form refers to a variable in another form, which is actually a reference to the element of a two form variable. B. Delphi class Three elements the three elements are property, method, Event this is the most important information you need to use a control. Property readable to write, method to raise a procedure or function, event allows the user to define a callback function. property is set in Object inspector in design time, and method is called in the program to understand this concept, helping you not to be disoriented when you look at help. C. Note on the property the change in the property is not necessarily just reading and writing a variable, it can trigger a lot of code. In the definition of property, this is generally written in the property Lookup:boolean read Getlookup write setlookup; Here, Getlookup and setlookup are function, so it is possible to change the property, in fact doing a lot of work. D. The location of the code is sometimes important when it is important to call specific code, the window is all message-driven and the code that is never triggered is not compiled into the program at all. You'll see in Delphi 3 that it's not going to be hit with a blue dot at all. And the code can be reentrant!!!! This issue will be discussed in detail later.