Computer Level 2 vb Programming Course Chapter 10 Keyboard and Mouse Events

This chapter describes the lighted event process of keyboard and mouse.

KeyPress event

KeyPress events occur when a key on the keyboard is depressed
Precise Description: Press a key and we will trigger the KeyPress event with focus at this time.
The input focus can only be on one control. If the form has no active or visible control, the input focus is on the form.
We can use vb to automatically generate a keypress event like this

- keyAscii is used for individual controls. keyAscii is the ASCII code of the key.

   Private Sub Text1_Key Press(KeyAscii As Integer)
      if KeyAscii < 48 Or KeyAscii > 57 Then
      KeyAscii = 0
  End Sub

Enter 0 (48) ~ 9 (57) only

Private Sub Text1_KeyPress(KeyAscii As Integer)
  If KeyAscii < 48 Or KeyAscii > 57 Then
    KeyAscii = 0
End If
KeyAscii = 0
End Sub

Private Sub Text2_KeyPress(KeyAscii As Integer)
If KeyAscii >= 65 And KeyAscii <= 122 Then
  KeyAscii = 42
End If
End Sub

Private Sub Text3_KeyPress(KeyAscii As Integer)
If KeyAscii = 13 Then
  Printer.Print Text3.Text
End If
KeyAscii = 0

When learning database, the video screen introduces a method called abstraction and instantiation comparison.
10.1 Writing Password Program

Private Sub Form_Load()
  Text1.Text = ""
  	Text1.FontSize = 10 
  	 Label1.FontSize 12
  	  Label1.FontBold = True
  	  Label1.FontName = "Official script"
  	  Label1.Caption = "please input password"
End Sub
Private Sub Text1_KeyPress(KeyAscii As Integer)
Private Sub Text1_KeyPress(KeyAscii As Integer)
Static PWord As String
Static Counter As Integer
Static Numberoftries As Integer
If Numberoftries = 12 Then End
Counter = Counter + 1
PWord = PWord + Chr$(KeyAscii)
KeyAscii = 0
Text1.Text = String$(Counter, "*")
If LCase$(PWord) = "abcd" Then
  Text1.Text = ""
  PWord = 0
  MsgBox "Correct password"
  Counter = 0
  Print "Continue"
ElseIf Counter = 4 Then
  Counter = 0
  PWord = ""
  Text1.Text = ""
  MsgBox "Is the password correct?,Please input from the star"
End If
End Sub

KeyDown KeyUp event

KeyDown and KeyUp return keyboard status.
The control for which the parameters of the procedure are used, KeyCode As Integer Shift As Integer
KeyCode uppercase and lowercase letters are the same, because they all use a keyboard.

Conversion key, shift ctrl AL, he 001 010 100
We can build the following process
Private Sub Text1_KeyDown(KeyCode As Integer, Shift As Integer)

End Sub
KeyDown is an event that occurs when the keyboard is pressed, and KeyUp is an event that occurs when the keyboard is loosened.

When pressed, the label displays the scan code, which is clear when loosened.

Private Sub Text1_KeyDown(KeyCode As Integer, Shift As Integer)
   Label1.Caption = Str$(KeyCode)
End Sub

Private Sub Text1_KeyUp(KeyCode As Integer, Shift As Integer)
  Label.Caption = ""
End Sub

We can use it.
Const Shift = 1
Const Ctrl = 2
Const Alt = 4
shift And Shift > 0
Shift And Ctrl > 0
Shift And Alt > 0

Mouse events
Click and double-click
Press and release

Press down

Parameters (Button As Integer,Shift As Integer,x As Single, y As Single)
Button Press the Mouse Key
SHift denotes shift Ctrl Alt status
Current position of X Y mouse cursor

Shape of mouse cursor

Setting mouse cursor shape

  1. Object. MousePoint = Set value

windows Rules
1. Represents functions available to users

Drag and drop

Manual drag and drop
Automatic Drag and Drop

Keywords: ascii Database Windows Attribute

Added by mpunn on Thu, 15 Aug 2019 15:49:49 +0300