A keystroke combination that serves as a shortcut for an element of the user interface.
A generic term that refers to the use of such technologies as ActiveX controls, scripting, and database access in Web pages.
A set of component technologies that enables software components to interact with one another in a networked environment, regardless of the language in which they were created. ActiveX controls are 32-bit, which means that they only function under Windows 95 and Windows NT.
An application to assist VBScript developers in inserting ActiveX controls into Web pages. The ActiveX Control Pad is downloadable free from the Microsoft Web site at http://www.microsoft.com/workshop/author/cpad/download.htm.
A location on the Microsoft Web site where you can preview and download ActiveX controls from Microsoft and a number of other developers. http://www.microsoft.com/activex/gallery
A generic term that refers to support in Microsoft Internet Explorer for Visual Basic scripting (VBScript) and Javascript (JScript).
An object provided by a control's container that suggests default properties to the control.
A set of procedures that represents the programmable elements of a software system. For example, your program can issue calls to the Windows API in order to get the Windows operating system to create windows, draw graphics, open files, and do the other things an operating system does.
A value passed to a procedure.
A set of elements storing the same type of data. Each element of an array has a unique identifying number, called an index. In Visual Basic 5.0, many computations requiring arrays are better done with collections instead.
A programming language feature that conditionally halts your code. You use assertions when testing Visual Basic applications by using the Assert method of the Debug object. If the assertion evaluates to False, your code is paused on the line that contains the Assert method.
A process that performs its work in the background, without preventing the remainder of the application from doing its work. For example, in Visual Basic 5.0, property values of controls can be downloaded asynchronously, enabling the control to continue working even though the property has not finished downloading.
A technology used by Microsoft Internet Explorer to verify that downloaded software (such as an ActiveX control) came from a reputable source. Downloaded files can be verified because they are digitally signed by their creators.
An object that is exposed to other applications or programming tools through Automation interfaces. Applications that expose an Automation interface can be programmed just like other types of software objects. Microsoft Word, Microsoft Excel, and Microsoft Internet Explorer are examples of applications that can serve as Automation objects. (They were formerly referred to as OLE Automation objects.)
An expression that evaluates to either True or False. In Visual Basic, False is equal to 0 and True is equal to -1.
A mode of code execution used for debugging. In Break mode, the developer can use the Immediate window, step through code, and use a number of other debugging features of the Visual Basic IDE. To place a running application into Break mode, you use the menu command Run, Break or the keystroke shortcut Ctrl+Break.
A procedure that encounters an unexpected condition that prevents it from carrying out its calculations. Compare with error.
A way of passing the address, rather than the value, of an argument to a procedure. This allows the procedure to access the actual variable. As a result, the variableÕs actual value can be changed by the procedure to which it is passed.
A way of passing the value, rather than the address, of an argument to a procedure. This allows the procedure to access a copy of the variable. As a result, the variable's actual value can't be changed by the procedure to which it is passed.
See cabinet file.
A compressed file that includes software components to be installed on a user's computer over the Internet. You can create cabinet files using the Setup Wizard. Also called CAB files.
A procedure referring to or executing another procedure.
The formal definition of an object. A class is used to create instances of software objects. Classes define the properties of the object and the methods used to control the object's behavior.
A Visual Basic file that can contain code. Typically, code modules end in the file extension .BAS.
An object that contains a set of related objects. In Visual Basic, you can create collections to store data as an alternative to using arrays.
Text within a piece of code that is not interpreted or executed. In Visual Basic, comments are set off with a single apostrophe (') or the Rem statement.
An operator that tests a quantitative relationship between two or more values or
expressions.
The process of taking a project's code components and making an EXE or OCX file out of them. You can distribute compiled files to users.
See Component Object Model.
A list box that drops down when clicked to expose a list of choices. Also referred to as dropdown lists.
A specification for reusable software components. ActiveX controls fall under the DCOM, or Distributed Component Object Model specification, which in turn falls under the COM specification.
A control that resides in an ActiveX control project. You can place one or more constituent controls in your ActiveX control project in order to use the functionality of those constituent controls.
An object that can house another object. For example, a Visual Basic form can be a container to an ActiveX control; a PictureBox can be a container to a CommandButton and ActiveX controls you create can act as containers to other ActiveX controls.
A programmable element (usually an element of the user interface). Examples of controls are the text box, the combo box, and the command button. In Visual Basic, "control" also can refer to certain programmable objects that are not part of the visible user interface, such as the timer control or the ActiveX preload control.
The visual design element of an ActiveX control. You use the control designer in the Visual Basic IDE to build the visual look of your control. Every ActiveX control project built in Visual Basic has a control designer-even controls that are invisible at runtime. Control designers are analogous to forms in Visual Basic EXE projects.
The software development kit used by C++ programmers to create OCX controls. Superseded by the ActiveX Development Kit.
A Visual Basic project that can be used to make an ActiveX control. Control projects are comprised of a control designer and, optionally, other components such as forms, code modules, and resource files.
A generic term referring to ActiveX, OCX, or VBX controls.
A specific range of allowed values for each Variant subtype.
The different types of variables that can be processed by a programming language. VBScript has only one data type, the Variant, which has many subtypes; variants can contain textual, numeric, or other information. Also see data ranges.
Any expression that can be interpreted as a date. This includes any combination of date literals, numbers that look like dates, strings that look like dates, and dates returned from functions. A date expression is limited to numbers or strings, in any combination, that can represent a date from January 1, 100 through December 31, 9999.
See Distributed Component Object Model.
In code, the process of identifying variables or function calls before using them. In Visual Basic, only API calls, arrays, and object variables must be explicitly declared (unless you use Option Explicit, in which case all variables must be explicitly declared).
The process of locating and removing bugs from code.
The act of assigning a property of your UserControl to one of its constituent controls. Delegating properties keeps you from having to write code to handle property changes. Instead, the inherent functionality of the constituent control is used.
The interface of a control used by a developer at control design time. A control designer is the control creation equivalent of a form.
An on-screen message box that conveys or requests information.
A form or object that has been changed and needs to be saved.
A protocol that permits software objects to interact over networks (including the Internet). Previously called Network OLE.
Dynamic Link Library, a type of Windows file that can be called from an application. DLLs can hypothetically be shared between applications.
The process of transferring information from a remote computer to your computer. On the Internet, you can use a file transfer utility (such as FTP) to download or upload files. You also download files using a Web browser.
See DLL.
An object that resides in another object. ActiveX controls and Java applets, for example, are said to be embedded in HTML pages through the use of the <OBJECT> tag.
A special value that indicates that a variable has never been initialized. In Visual Basic expressions, Empty can be equivalent of either zero or a zero-length string ("").
A control that is capable of receiving user input. You enable or disable controls to reflect the state of the user interface.
A method of declaring a related group of constants. You declare an enumeration in Visual Basic using the Enum statement.
A procedure that arrives at an incorrect result. Compare with bug.
A whole number in the range 0 to 65,535, inclusive, that corresponds to the Number property of the Err object. When combined with the Name property of the Err object, this number represents a particular error message.
A procedure that deals with an error condition in a procedure. In Visual Basic, error-handlers are declared with some form of the On Error statement.
The process of determining the value of an expression.
An occurrence that takes place while an application runs. Events are usually user-initiated. Button clicks, windows opening, and menu commands are examples of events. Code triggered to run when events take place are called event procedures.
Code that is run as the result of an event, such as a click on a command button. See event.
A Visual Basic project that can be made into a stand-alone, executable application. The Visual Basic Control Creation Edition can't create executables; however, you can use EXE projects to test ActiveX components. Compare to control project, a Visual Basic project that can be used to make an ActiveX control.
A combination of keywords, operators, variables, and constants that yield a string, number, or object. An expression can perform a calculation, manipulate characters, or test data.
An object that enables your ActiveX control to communicate with and manipulate properties of its container.
A list of computer files contained on a disk or drive. May be nested to facilitate organization of data on the disk or drive. Called directories or subdirectories on DOS and Unix systems.
One complete collection of letters, punctuation marks, numbers, and special characters with a consistent and identifiable typeface, weight, posture, and font size. Sometimes used to refer to typefaces or font families.
A user interface, usually comprised of input controls such as text boxes and buttons. In HTML, form refers to a page that takes information inputted into a Web browser and submits it to a Web server. In Visual Basic, a form is the basis of the user interface.
A procedure that can access private data of procedures declared in the same module as the friend procedure.
A procedure that returns a value. Compare with subroutine.
The unique identifier of OLE objects or servers, including ActiveX controls. Your control's GUID is assigned to it by Visual Basic at the time it is compiled.
A variable that is accessible from any procedure in the application.
A compressed format for storing graphics.
A list of uniform resource locators stored by a Web browser. The history list stores a list of all the Web pages the user has previously visited.
HyperText Markup Language, the language that dictates the basic layout of World Wide Web pages. HTML can be extended by various means, including scripting (such as VBScript and JScript) and embedded objects (such as Netscape plug-ins and ActiveX controls).
A Microsoft ActiveX control designed to extend the functionality of style sheets within Microsoft Internet Explorer.
A word or series of words that are clickable. Clicking on a hyperlink enables a user to jump from one document to the next, or from one area of a document to another area in the same document. Also called hypertext.
See hyperlink.
See integrated development environment.
A window in the Visual Basic development environment that enables the developer to issue commands to an application running in Break mode.
A number that uniquely identifies an element of an array.
A principle dictating that an ActiveX control must not be able to harm a user's computer no matter what its initial properties are set to. Compare with safety, script safety.
To insert a control into a container, either at design time (by drawing the control using the mouse) or in code.
The user interface of a software development environment. When you are developing applications with Visual Basic, you are said to be in Visual Basic's IDE. Other development environments have different IDEs.
The set of functions and data exposed by a programmable software component. For example, the interface of an ActiveX object is comprised of the objectÕs properties, methods, and events.
Microsoft's Web browser, available for free download at http://www.microsoft.com/ie/default.asp.
A file format that stores images in a compressed format. Support for JPEG files (in the PictureBox control) is a new feature of Visual Basic 5.0.
A scripting language based on the Java programming language. JScript is comparable to VBScript in its functionality, but uses Java-like syntax.
The legal right to use a piece of software. ActiveX controls can support licensing. The license for a control is embedded in the user's system registry when the user installs the control. For licensed controls designed to be distributed over the Web, you must use a special tool to create a temporary license for the control.
The period of time a variable exists, depending on the level at which it was declared. Global and static variables persist until the application is done running, while variables declared at the procedural level are only valid while the procedure they were declared in is still running. See also procedure level, scope.
The location and language of a user; used for localization purposes. For example, U.S. English, Swiss, German, and Albanian are examples of locales. In Windows, you set your locale through the Regional Settings control panel.
The process of translating software for international use. This entails, among other things, translating the textual elements of the user interface into the local language. In Windows, the operating system is responsible for some elements of localization, such as the format of date and time values. Resource files containing string resources are often used in the process of localization.
A set of program instructions that execute repeatedly until a condition is satisfied. In Visual Basic, the Do...While and For...Next statements are looping structures.
See multiple document interface.
A procedure that causes a programmable object to perform an action. Compare with property, a characteristic of an object.
A Visual Basic file that contains code.
A Windows interface style in which all of an applications' windows are housed in a large window known as the parent window. Compare with single document interface.
A code structure that occurs within another identical code structure; for example, an If...Then statement contained inside another If...Then statement.
See Distributed Component Object Model.
In Visual Basic, a special value that indicates that an object variable is not associated with an object. Evaluates to zero or an empty string ("") in an expression.
A value indicating that a variable contains no valid data. A variable will typically be set to Null in a database context, in situations where a field contains no data or a recordset contains no records.
Any expression that can be evaluated as a number. Elements of the expression can include any combination of keywords, variables, constants, and operators that result in a number.
Generally, a self-contained piece of code embedded in another application. Objects provide various interfaces (such as properties, methods, and collections) to permit programmers to access them. VBScript objects are either ActiveX controls or Java applets. Objects are inserted into an HTML page through the use of the <OBJECT> tag.
A facility that displays the interface of the programmable objects available to your project.
The interfaces made available by an object. The Microsoft Internet Explorer Scripting Object Model, for example, lists the properties and methods of the Web browser accessible from VBScript. You can create objects in your projects that have object models of their own through the use of classes.
OLE Custom Control, a type of software object designed to be embedded in applications. This term has been supplanted by the term ActiveX, but the underlying technology is nearly identical; you can often use most OLE controls in the same contexts you'd use ActiveX controls.
Originally an acronym for Object Linking and Embedding, it now refers to a broad range of interoperability protocols and standards.
A logical or mathematical symbol that serves as part of an expression in code. Plus and minus signs are examples of math operators; the greater-than symbol (>) is an example of a logical operator.
A control event that is triggered when the control needs to redraw itself. Controls need to redraw themselves when they are temporarily obscured by other windows, for example.
An element of the Visual Basic interface that can use Visual Basic's graphics methods (such as Line and PSet). Examples of painting objects are Forms and PictureBoxes.
An element of the user interface that can store and display a graphic file.
A collection of statements in a programming language. Examples of procedures are functions, which can return a value, and subroutines, which do not.
Elements of a program that determine whether a piece of code is executed and, if it is executed, how many times it is executed. The If...Then...Else statement is an example of conditional program flow. The Do While...Loop statement is an example of looping program flow.
The collection of all files that comprise a software application's code. A Visual Basic project file contains references to all the forms, code modules, controls, class files, resources used by the application.
The window in the Visual Basic IDE that enables you to see the components of your project in outline form.
A file that contains references to all the files used in a project. Project files save you time because you don't have to load the individual components of a project separately. Visual Basic 5.0 gives you the new ability to open multiple projects simultaneously.
A file that contains references to one or more Visual Basic projects. Project group files enable you to easily open more than one Visual Basic project at a time; they are new in Visual Basic 5.0.
An attribute of a programmable object. Properties define characteristics such as size and color. Compare with method, a way to tell a programmable object to perform an action.
An object that represents the place where design-time properties of an ActiveX control are stored. You write code in the ReadProperties and WriteProperties events of the UserControl so a control can store its design-time properties.
The Visual Basic procedure that is executed when a user reads a property of an object. You use Property Get procedures in classes and ActiveX controls.
The Visual Basic procedure that assigns a variable to an object. You use Property Let procedures in classes and ActiveX controls.
A dialog box that enables a user to view and set an ActiveX controlÕs properties. Also referred to as a property sheet.
The Visual Basic procedure that assigns an object variable to an object. You use Property Set procedures in classes and ActiveX controls.
A component of a database that retrieves data from one of more tables.
A system file containing software and hardware information. ActiveX controls must be registered before they can be used on a particular computer. Installing a control that has been packaged with a Setup application registers the control; you can also register a control manually using a utility called Regsvr32.
A utility that takes a resource script and compiles it into a resource file.
A resource is a piece of data-a string, a bitmap, a sound file-that is compiled along with your control or VB application.You use resources to avoid having to refer to files on disk; instead, the file resides in the compiled EXE (or OCX) you distribute to users. You create resource files using a resource compiler.
A text file that gives the resource compiler information on what files to compile into a resource file and how to identify them.
The time when code is running-as opposed to design time, when you are writing the code. Some object properties can be changed only at runtime, while some can be changed either at design time or runtime.
An error that occurs when code is running. A run-time error results when a statement attempts an invalid operation.
The principle that an ActiveX control distributed over the Web must not be capable of harming a user's computer. Safety is divided into script safety and initialization safety.
The Visual Basic property that determines the height of an object in the current measurement system (as determined by the ScaleMode property). For example, the Width of a form might be 4800 twips, but its ScaleWidth might be much smaller if its ScaleMode property is set to pixels. Because the number of twips per pixel is system-dependent, it makes sense to use the ScaleWidth and ScaleHeight properties, rather than absolute Width and Height properties, when computing dimensions of your control.
The Visual Basic property that determines the width of an object in the current measurement system. See ScaleHeight.
Defines the visibility of a variable, procedure, or object. For example, a variable declared as Public is visible to all procedures in all modules in a project. Variables declared in procedures are visible only within the procedure and lose their value between calls.
A principle that dictates that an ActiveX control must not be allowed to harm a user's computer no matter how it is used in a scripting language. Compare with safety, initialization safety.
See single document interface.
Software Development Kit. Often, software companies (most notably Microsoft) will distribute SDKs that permit developers to write to application programming interfaces (see API). The ActiveX SDK permits Visual C++ developers to create ActiveX controls.
A utility used to package software for distribution. The Setup Wizard creates a Setup application. Users run Setup applications to install software on their computers.
A file that has been digitally marked with information about its creator. Authenticode is a method of signing a file.
A Windows interface style in which the application's interface is comprised of a single window with no background parent window. Compare to multiple document interface.
A language for issuing requests to database servers. The RecordSource property of a Data control can be an SQL query.
A series of text characters.
A procedure that does not return a value. Compare with function.
A place in a database where data is stored. Tables are comprised of fields, or columns, and records, or rows.
The default unit of measurement in Visual Basic painting objects. There are 1,440 twips to the inch.
Server and path information that locates a document or other file on the Internet; for example, http://www.domain_name.com.
The person who uses the software created by a software developer. To an application programmer, a user uses their executable application; to an ActiveX control developer, a user is another programmer.
A self-contained ActiveX control whose appearance is entirely generated by graphics methods in code, as opposed to a control whose appearance is generated by constituent controls. The appearance of a user-drawn control is generated by graphics methods placed in the UserControl's Paint event.
A control you create in Visual Basic. The UserControl object is analogous to the Visual Basic Form object.
The elements of a software application with which a user can interact. Forms, command buttons, and list boxes are all examples of parts of a user interface; most, but not all, ActiveX controls are designed to serve as part of a user interface.
The process of ensuring that a piece of data is valid before processing that data.
A named storage location that can contain data that can be modified during program execution. Each variable has a name that uniquely identifies it within its level of scope. Variables also have a specific lifetime depending on where and how they were declared (see lifetime, scope). Variable names must begin with an alphabetic character, can't contain an embedded period or type-declaration character, must be unique within the same scope, and must be no longer than 255 characters.
A data type unique to Visual Basic. Variants can store nearly any type of data: text, numbers, or object references.
Visual Basic Script, a subset of Visual Basic. One of the Web programming languages understood by Microsoft Internet Explorer. You can use VBScript to manipulate ActiveX controls in a Web page.
Visual Basic Extension, a 16-bit component technology that predates OCXs and ActiveX controls. VBXs are usable in the 16-bit versions of Visual Basic only, unlike ActiveX controls, which can be used in a number of development environments.
A set of functions and subroutines that enable you to place calls to the Windows operating system. In Visual Basic, you place Windows API calls to perform tasks that are not possible to do using Visual Basic.
A Windows application programming interface to the TCP/IP networking protocol.