An array is a set of values, which are termed elements, that are logically related to each other. For example, an array may consist of the number of students in each grade in a grammar school; each element of the array is the number of students in a single grade.
Types of Arrays
- One dimensional array.
- Multi-dimensional array.
The basis rules for naming arrays are as follows:
- The data type can be any valid data type such as int, float, char structure or union.
- The name of an array must follow naming rules of variables .
- the size of the array must be zero or a constant positive integer..
Obtaining an array is a two-step process. First, you must declare a variable of the desired array type. Second, you must allocate the memory that will hold the array, using new, and assign it to the array variable. Thus, in Java all arrays are dynamically allocated.
An array is a linear data structure that is a collection of data elements of the same type stored on a contiguous memory location. Each data item is called an element of the array.
In computer science, an array data structure, or simply an array, is a data structure consisting of a collection of elements (values or variables), each identified by at least one array index or key. They are also used to implement many other data structures, such as lists and strings.
Clearing a Element Ranges from a Visual Basic ArrayThe contents of array elements may be cleared using the Array. Clear() function. This function takes three parameters, the array, the start index and the number of elements from the index to clear.
A command button performs a task when the user clicks the button. You use a CommandButton control to begin, interrupt, or end a process. When clicked, a command button appears to be pushed in and so is sometimes called a push button. The most common event for a CommandButton control is the Click event.
The Visual Basic development environment contains these programming tools and windows, with which you construct your Visual Basic programs:
- Menu bar.
- Toolbars.
- Visual Basic toolbox.
- Form window.
- Properties window.
- Project Explorer.
- Immediate window.
- Form Layout window.
Creating Visual Basic Custom Controls
- Start a new project.
- Choose ActiveX control from the New Project dialog box.
- Add a picture box to the usercontrol - it looks like a form without a border.
- Add a timer with the interval property set to 50.
- Rename the picture box 'ScrollBox' and resize it to about 4000 wide and 700 in height.
Visual Basic was derived from BASIC and enables the rapid application development (RAD) of graphical user interface (GUI) applications, access to databases using Data Access Objects, Remote Data Objects, or ActiveX Data Objects, and creation of ActiveX controls and objects.
Visual basic programming language allows programmers to create software interface and codes in an easy to use graphical environment. VB is the combination of different components that are used on forms having specific attributes and actions with the help of those components.
- The Visual Basic IDE is made up of a number of components.
- Menu Bar.
- Tool Bar.
- Project Explorer.
- Properties window.
- Form Layout Window.
- Toolbox.
- Form Designer.
Binding Data to the Control. For the DataGrid control to work, it should be bound to a data source using the DataSource and DataMember properties at design time or the SetDataBinding method at run time. This binding points the DataGrid to an instantiated data-source object, such as a DataSet or DataTable).
In terms of Visual Studio Windows Form Applications, A Label is a control which is used to display some text onto the form whereas, A TextBox control is used to input data from the user.
Tool Box. Toolbox in Visual Basic.net 2008 consist of Controls, Containers, Menu Options, Crystal Report Controls, Data Controls, Dialogs, Components, Printing controls, that are used in a form to design the interfaces of an application.
In Visual Basic, a control array is a group of related controls in a Visual Basic form that share the same event handlers. One application of control arrays is to hold menu items, as the shared event handler can be used for code common to all of the menu items in the control array.
The Visual Basic Power Packs Line and Shape controls are a set of three graphical controls that enable you to draw lines and shapes on forms and containers. LineShape control -is used to draw horizontal, vertical, and diagonal lines. OvalShape control is used to draw circles and ovals.
Data Validation with VB.Net
- Permitted character check - useful for determining whether an input string contains valid characters.
- Type check - the data entered must be of the correct datatype.
- Format check - this sort of check is often applied to things like dates.
The MSFlexGrid control is an extremely useful tool for displaying information in a tabular form. You can place it on your Forms to present nicely organized data to the user. It is meant to display information in tabular form, but not for data entry.
Timer is a control in Visual Basic 2019 that that can be used to create applications that are time-related. For example, you can use the timer to create a clock, a stopwatch, a dice, animation and more. The timer is a hidden control at runtime, just like the engine of a car.
String functions are mainly used to manipulate the string in Visual basic. String functions are mainly used to manipulate the string in Visual basic. GetChar. Gets the character from the string of particular index number.
A procedure is a block of Visual Basic statements enclosed by a declaration statement ( Function , Sub , Operator , Get , Set ) and a matching End declaration. All executable statements in Visual Basic must be within some procedure.
An example of a basic loop is as follows:
- Do Debug. Print "hello" x = x + 1 Loop Until x = 10.
- Do While X <= 5 X = X + 5 Loop.
- Do X = 5+2 Loop Until X > 5.
- Do X = Calculate_Something If X > 10 then Exit Do End If Do_Something (X) Loop.
The List class is used to store generic types of collections objects. By using a generic class on the list, we can store one type of object. The List size can be dynamically different depending on the need of the application, such as adding, searching or inserting elements into a list.
