Page 92 - TCS ICT Book 8

The City School 2021-2022

How Does it Work?

• The Do…Loop structure does not increment
any counter variable automatically, so we have
included the instruction i = i + 1 to increment it by
one inside the loop.
• With the instruction lstResults.Items.Add(i & vbTab
& sum), we add one line in each loop to the
ListBox, containing the current counter value and
the current sum.
• The & operator is used to concatenate the
different values into a single line and the vbTab is
a predefined constant of Visual Basic representing
a tab space.
• The loop here runs for as long as the value of the
sum is smaller than 500.

4.11. Event Handling

Events are basically a user action like key press, clicks, mouse
movements, etc., or some occurrence like system generated

notifications. Applications need to respond to events when they
occur.

Mouse Event

Mouse events occur with mouse movements in forms and controls. Following are the

various mouse events:

Event Description

MouseDown It occurs when a mouse button is pressed

MouseEnter it occurs when the mouse pointer enters the control element

MouseHover it occurs when the mouse pointer hovers over the control
element

MouseLeave it occurs when the mouse pointer leaves the control element

MouseMove it occurs when the mouse pointer moves over the control
element

MouseUp it occurs when the mouse pointer is over the control element
and the mouse button is released

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