Chapter 3.LC, Problem 1RQ

Program Description Answer

When the content of a textbox is changed, the “TextChanged” event occurs.

Hence, correct answer is option “C”.

Explanation of Solution

TextChanged Event:

• If a control’s text property contents are getting changed, then the “TextChanged” event occurrs.
• The “TextChanged” event can occur by the following ways:
  • When the user is entering or deleting the text content on a controls text property.
  • When the application code assigns or removes the text content into the controls text property.

Example:

'Procedure code1

Private Sub btnAsign_Click(ByVal sender As Object,ByVal e As System.EventArgs) Handles btnAsign. Click

'The button click event assigns the text to 'the text box control

  txtT1.Text= “Karlson”

  End Sub

  'Procedure code2

Private Sub txtT1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtT1.TextChanged

'The label box text content is cleared when 'the text change event is occurred

  lblTotalPhones.Text = string.Empty

  End Sub

In the btnAsign_Click procedure, the string value “Karlson” is assigned to the text box control txtT1.

• As the text content is assigned to the text control, the TextChanged event occurs in the text box control txtT1.
• As a result, txtT1_TextChanged procedure is executed, and this event clears the text content from the label lblTotalPhones.