Visual basic programming

Text box:
In order to display or accept user input in the form of text like
name, customer ID, ETC., Visual basic provides you with this
controls. It is used to display text and allows the user to edit the data
in the box. A text box control is also called an edit field or edit
control. It displays the information entered at design time, entered by
the user, or assigned to the control in code at run time.
Command button:
Creates a button that the user can choose to carry out a
command. The user will click on this button and the computer will
perform the task associated with the button.
Activity does not stop with the invoice that you have generated.
A copy may have to be sent to the commercial tax department, the
credit card company, the head office, and so on.

Label box:
It allows you to display text that you don’t want the user to
change, such as a caption under a graphic. When you want to print
the voices, you need to know if the customer is going to pay by
cash or toque, or credit card. This means that the billing clerk has
to select one from the various options available. For this Visual
basic has the option button control.
Check box:
Creates a box that the user can easily choose to indicate if
something is true or false, or to display multiple choices when the
user can choose more than one. There are many more controls that
Visual basic provides that may not be used in the immediate
context. Let us take a look at the other controls that are part of the
standard set of controls available on the toolbox.

Combo box:
The user can either choose an item from the list or
enter a value in the text box. The new value entered can
be added to the existing data. The list box and the combo
box display data usually from a database. In order to
access data and to manipulate data in a database like
access, SQL server, etc. Visual basic provides a control
called the data control.
Image control:
This is very similar to the pictures box control. Images
displayed in an image control can only be decorative and
use fewer resources than a pictures box.

 Moving from one drive to another : The DriveListBox
 Moving from one directory to another : DirListBox
 List file(s) in a dictionary : FileListBox

 The DriveListBox control:
This is a drop-down list box that will display the list
of drives on your computer. It gets all information from the
operating system and allows the user to select a drive of the
choice. Selecting a particular drive records a change in the
Drive property of the DriveListBox.
 The DirListBox control:
A drop-down list box that displays a hierarchical list of
directories in the current drive.
 The FileListBox:
Displays all files in the current Directory or Folder.
Allows users to set up search criteria for files.
These three controls used together can create an
elegant interface that will allow the user to locate a file on
his computer without any sweat.

Add the Common Dialog control to your toolbox by
Right clicking on the toolbox and selecting ‘Components’
from the pop-up menu. Next select ‘Microsoft common
dialog control 6.0 from the list of components. You will see
this as a control on your toolbox.
Draw it on your form. Please note that this control does
not have an interface that the user will see and work on.
During runtime it is not visible. However

The common dialog box control made our life easier
by giving us a simple and easy way to provide the
necessary interface to the user. We were able to create a
small application that would allow the user to create a
new file or open an existing file, add text to it, save the
changes and print the contents of the file as well.

The tree view control is a very interesting control to work
with. With this control you can display the data as a hierarchy.
The windows explorer is built around a tree view control. It
displays the drives, directories, subdirectories and files in the form
of a hierarchy. You can use the same control to display the data
from a database. For example, you can display the list of
customers, the invoice no and date for each customer, and for each
invoice the items therein and so forth.

Working with the tree view control:
Draw a Tree View control on your form. Add the following code to the
form load event.
Private Sub Form_Load()
Dim NewNode As Node
Set NewNode = TreeView1.Nodes.Add(, , ”c”, ”customer”)
Set NewNode = TreeView1.Nodes.Add(“c” , tvwchild , “child1”,
“Customer_Code”)
“Customer_Name”)
“Customer_City”)
End Sub

What is database?
A database can be defined as a collection of records stored in
tables. It has a set of rules and tools to manage these records.
There are different type of data bases, each with it’s own format.
the most commonly known data base type are:
 Relational database
 Network model
 Hierarchical model

user 1’s view user 2’s view
Supplier Name
Address
Amount Due
Supplier Name
Address
Physical view

 The database grid control display fields from a record set
object as a series of rows and columns, and enables
manipulation of this data.
 The data aware DBgrid control is like an enhanced grid
control. Once the properties are set, gets populated
automatically with the data from the record set object.
 You only need to fix the number of columns. The total
number of rows is indeterminate. A DB Grid control can
have as many rows as the system resources can support
and about 1700 columns.
 Lets us see the DB Grid in action:
start a new project.
On the form add the following control
 One data control
 One DB grid control

 If you don't have the DB grid control, as part of your tool
box, right click on the tool box. Select components from
the were pop-up menu. From the list displayed there after,
click on DB grid control. click on OK you have it on your
toolbox.
 Set the properties for the controls as follows
Data control
Data base sources: C:/VB/Bibli.mdb
Records sources: Publishers
DB Grid control
data sources: data1

 To open a data base, we have to use the open database
method. This method opens a specified database in a
workspace object and return a reference to the data base
object that represents it.
 Syntax:
Set database = workspace.OpenDatabase (dbname,options,read-
only,connect)
The OpenDatabase method syntax has three parts.
 Databsae
 Workspace
 Dbname
 Options
 Read-only
 Connect

Visual basic programming

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