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How to carry on the comprehensive parsing of Visual Basic object, aiming at this problem, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

Visual Basic is still quite commonly used, so I have studied the use of Visual Basic objects, and I hope it will be useful to share it with you here.

When you create an application in Visual Basic, it's time to deal with objects. You can use objects provided by Visual Basic, such as controls, forms, and data access objects. You can also control another application object within one Visual Basic application. You can even create your own objects and define their properties and methods.

What is the object?

An object is a combination of code and data that can be handled as a unit. An object can be part of an application, such as a control or form. The entire application is also an object. The following table lists several types of objects that may be used in Visual Basic:

Where do objects come from? every object in Visual Basic is defined by a class. Using the relationship between the biscuit mold and the biscuit as an analogy, you will understand the relationship between the object and its class. The cookie mold is a class. It determines the characteristics of each cookie, such as size and shape. Create objects with classes. The object is cookies.

Here are two more examples to further illustrate the relationship between classes and objects in Visual Basic.

1. On the toolbox of Visual Basic, controls represent classes. Until these objects, called controls, are drawn on the form, they do not actually exist. When you create a control, you are copying the control class, or creating an instance of the control class. This class instance is the object referenced in the application.

two。 The forms that operate at design time are classes. At run time, Visual Basic establishes a class instance of the form. The Properties window displays the class and Name properties of objects in the Visual Basic application.

Treat objects as copies of the original class, thus creating all objects. Once they exist as a single object, the properties can be changed. For example, if you draw three command buttons on a form, each command button object is an instance of the command button class. Each object has a set of common features and functions (properties, methods, and events) defined by the class. However, each object has its own name, can be set to valid or invalid, can be placed in a different location on the form, and so on.

For simplicity, most of the content outside this chapter will not refer too much to the object's classes. For example, just remember that the term "ListBox control" means "an instance of a listbox class."

What can you do with an object?

Object can provide ready-made code, saving the trouble of writing. For example, you can create your own dialog boxes to open and save files, but you don't have to. Instead, it uses the CommonDialog control (an object) provided by Visual Basic. Although users can also write programs for schedule management and resource management, they don't have to. You can also use the Calendar, Resources, and Task objects provided by Microsoft Project here.

Visual Basic can combine objects from other sources

Visual Basic provides tools for combining objects from different resources. You can now combine the powerful features of Visual Basic with applications that support automation (formerly known as OLE automation) to create custom solutions. Automation is a feature of the component object pattern (COM), an industry standard used by applications to display objects to develop tools and other applications.

You can combine controls within Visual Basic, or you can use objects provided by other applications. Consider putting the following objects into a Visual Basic form:

1.Microsoft Excel Chart object

2.Microsoft Excel Worksheet object

3.Microsoft Word Document object

A checkbook application that can be created with these objects. Because you don't have to write code, you save a lot of time by rebuilding the functionality already provided by objects such as Microsoft Excel and Word.

Preliminary use of objects for Visual Basic objects

The Visual Basic object supports properties, methods, and events. In Visual Basic, the data (settings and properties) of an object are called properties, and the various processes that can be manipulated on an object are called methods. Events are actions that can be recognized by an object, such as clicking a mouse and pressing a keyboard key, and you can write code to respond to the event.

Changing the properties of an object can change the properties of an object. In the case of the radio, one of the properties of the radio is volume. In Visual Basic jargon, the radio has a "Volume" attribute, and the volume can be adjusted by changing its value. Suppose the volume value of the radio can be set between 0 and 10. If you can control the radio through Visual Basic, you can write code in one process to increase the value of the "Volume" property from 3 to 5 to make the sound louder:

Radio.Volume = 5

In addition to properties, objects have methods. Methods and properties are part of the object. Generally speaking, a method is an action to be performed, and a property is a property to be set or retrieved. Take dial-up calls as an example. It can be said that the phone has a "dialing" method, and the syntax for dialing a 7-digit phone number is:

Phone.Dial 5551111

Objects and events. The event is triggered when some aspect of the object changes. For example, there may be a "VolumeChange" event on the radio. There may be "Ring" events on the phone, and so on.

Control objects with attributes

Individual properties vary depending on when their values can be set and obtained. Some properties can be set at design time. You can set the values of these properties in the Properties window without writing any code. Some properties are not available at design time; therefore, these properties can only be set at run time through the code.

Properties that can be set and obtained at run time are called read-write properties. Properties that can only be read at run time are called read-only properties.

Set property value

Set the value of the property when you want to change the appearance or properties of the object. For example, you can change the contents of a text box by changing the Text property of the TextBox control.

Set the property value with the following syntax:

Object.property = expression

The following is the statement to set the property:

Text1.Top = 200' set the Top property to 200TWIPS (twips). Text1.Visible = True' displays the text box. Text1.Text = "hello" 'displays "hello" in the text box.

Read attribute valu

If you want to know the state of an object before the code performs an additional action, such as assigning a value to another object, read the property value. For example, you can return the value of the Text property of the TextBox control before running the code to determine the contents of the text box, where the code may change the value.

In most cases, attribute values can be obtained using the following syntax:

Variable = object.property

Property values can be part of a more complex expression without having to assign attributes to variables. The following code calculates the Top property of a new member in the control array, which is equal to the Top property of the previous member plus 400.

Private Sub cmdAdd_Click ()'[statement] optButton (n). Top = optButton (n Mel 1). Top + 400' [statement] End Sub

Hint if you use not only one property value at a time, but also store that value in a variable, the code executes faster.

Communication between objects

In addition to using creation in Visual Basic objects, you can also communicate with other applications and manipulate objects of other applications in your own applications. The ability to share data between applications is one of the key features of the Microsoft Windows operating system. With Visual Basic, communicating with other applications becomes extremely flexible.

This is the answer to the question on how to fully parse Visual Basic objects. I hope the above content can be of some help to you. If you still have a lot of doubts to be solved, you can follow the industry information channel to learn more about it.

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