Visual: Refers to the development of a graphical user interface (GUI) - no need to write a large number of code to describe the appearance and location of the interface element, and simply add a predetermined object to the screen.
Basic: Refers to the Basic (Beginners All-Purpose Symbolic Instruction Code), a language that is widely used in computing technology development history. Visual Basic has further developed on the basis of the original Basic language, and has included hundreds of statements, functions, and keywords, many of which have direct relationships with Windows GUI.
Visual Basic Scripting Edition (VBScript): is a widely used scripting language, which is a subset of the Visual Basic language, which can be embedded in the HTML language, used for web design, such as the ACTIVE Server Page file.
VB's development: VB4.0 is introduced in 1995 in 1995, which can also be used to write a 16-bit application of Win3.x platforms or 32-bit applications for Win95 platforms; VB5.0 is mainly used to write The 32-bit application of the Win95 platform, compared with the VB4.0 mainly expands the functions of database, ActiveX, and Internet; VB6.0 is launched with Win98 in 1998, further strengthens database, internet, and creation control functions. .
ActiveX: is a trademark name of the visual control structure based on Component Object Model (COM). It is a method of encapsulation technology that provides a method of encapsulating COM components and placing it into an application (such as a web browser).
Components Object Model (COM): It is a way to communicate with each other software components. It is a binary and network standard that allows any two components to communicate with each other, regardless of whether they are running on what computer (as long as the computer is connected), no matter what the computer is running (as long as the operating system supports COM No matter what language is written in any language.
The relationship between attributes, methods, and events
VB's forms and controls are objects with their own properties, methods, and events. The properties can be regarded as the nature of an object, regarding the method as an object, regarding the event as an object response.
Objects in daily life, with balloons playing with children also have attributes, methods, and events. The properties of the balloon include some properties that can be seen, such as its diameter and color. Other properties describe the state (inflated or unfire) or unacceptable nature, such as its life. By definition, all balloons have these attributes; these attributes will vary depending on the balloon.
Balloons also have methods and actions inherent. Such as: Inflating method (with helium full of balloons), deflation method (gas in the balloon) and the rise method (let go of the balloon away). All balloons have these capabilities.
Balloons also have predefined responses to certain external events. For example, the balloon is alerting the incident in which it is quenched, and the response to the letters is boosted.
In VB programming, basic design mechanisms are: changing the properties of the object, using object methods, and write event processes for object events. The job to do when programming is to decide which attributes should be changed, what methods are called, and which events are responding to getting hopeful appearance and behavior.
Event drive model
In a traditional or "procedure" application, the application itself controls which part of the code and what order executes code. Execute the program from the first row code and execute it in the application in the application, the process is called if necessary.
In an event-driven application, the code is not performed in a predetermined path, but performs different code snippets when responding to different events. The event can be triggered by the user, or the message from the operating system or other application, even triggered by the application itself. The order in which these events determine the order of code execution, so the path to the code passed at each runtime is different. Since the order in which the event is unpredictable, the "various status" must be performed in the code. When some assumptions are made (for example, before running the process of running a certain input field), the input field must contain a certain value), should organize the structure of the application to ensure that the hypothesis is always valid (for example, in input The command button that is prohibited using the startup process before value values.
Event can also be triggered in the execution code. For example, changing the text in the text box in the program will trigger the Change event of the text box. If you contain a code in the Change event, the execution of the code will result. If it is assumed that the event can only be triggered by the user's interaction, it may generate unexpected results. For this reason, it is very important to understand the event-driven model when designing an application and keep in mind.
Interactive development
Traditional application development processes can be divided into three obvious steps: encoding, compiling and testing code. However, Visual Basic is different from traditional language, which uses interactive ways to develop applications, so that there is no significant limit between three steps.
The VB explains when the programmer inputs the code, instantly capture and highlights most syntax or spelling errors. It looks like an expert in the monitor code.
In addition to instant capture errors, VB also compiles the code in part when entering the code. When you are ready to run and test your application, you can complete compilation only for a short time. If the compiler discovers an error, the error highlights the code in the code. At this time, you can correct the error and continue to compile without starting from the beginning.
Due to the interaction characteristics of VB, the effect of code run can be tested at the time of development without having to wait until the compilation is completed.
