How Can I Simulate The Down Key Using Sendkey In Vb.Net

Question

1.57/5 (4 votes)

See more:

I made this vb.net program where i loaded all my songs from a particular folder in a listbox. I have two buttons- button1 is for loading the songs and button2 is what i intended for is simulating the down arrow key, so that whenever i click on button2, i go to the next song. But here is the problem, i used a timer to simulate the down arrow key and whenever i click on the button2 , the timer starts and the down arrow key keeps going continuously without stopping. This is not what i want, my goal is that the when the click on button2, it should just go 1 step and not keep going continuously. I tried using loops to stop that but nothing worked. Any idea how i can solve this issue.
Heres my code-

VB

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click


        Timer1.Enabled = True

 End Sub

 Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick

SendKeys.Send("{DOWN}")

End Sub

Posted 14-Sep-14 2:00am

Rebecca1995

Updated 14-Sep-14 3:51am

ChauhanAjay

v2

Add a Solution

Comments

Wombaticus 14-Sep-14 9:05am

Add
Timer1.Enabled = False
in the Timer!_Tick event. But what's the point of the Timer? WHy not just put your Sendkeys in the Button click event?

Sergey Alexandrovich Kryukov 14-Sep-14 9:11am

There is no point of timer, and probably there is no a point of SendKeys. Please explain what are you trying to achieve and why.
—SA

Sinisa Hajnal 15-Sep-14 3:12am

Just select next index in whatever list you're using for the song list. No need to call SendKeys or any other "magic function". Timers you can disable, but why would you even have them!?

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Sheepings · Accepted Answer · 2014-09-15T07:40:00

You can add this as a solution, as I have tested this and its working fine. Hope it helps.

VB

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load 'When formloads
    AddHandler eTB.KeyDown, AddressOf eTB_Ev 'Add a handler for the textbox we created in code.
    Me.Controls.Add(eTB) 'Now add the control
End Sub

Dim eWin_KeyDown As Integer = &H100 'Declared for API
Dim eWin_KeyUp As Integer = &H101 'Same ^

Public Declare Function eAPISMessage Lib "user32.dll" Alias "SendMessageA" (ByVal hWnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As String) As Integer
'The function above will be used to execute the send command.

Public WithEvents eTB As New TextBox 'Create an instance of a textbox.

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    eTB.Focus() 'Give the TextBox Focus.
    eAPISMessage(eTB.Handle.ToInt32, eWin_KeyDown, eWin_KeyUp, CStr(0)) 'Using our API call we can send the message of keydown to the keydown event
End Sub

Private Sub eTB_Ev(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs)
    'Dont add a handler because the API function is calling this sub and passing the key press. (Adding Handles eTB.KeyPress will only cause you to receive it twice.)
    MsgBox("Keydown pressed from Command3 button.") 'Remove this once you are happy it works.
    Try 'Use a try block to catch any index exception errors which you might have.

        'I also don't check for a key press for a specific key press because its passed by the API function.

        If ListBox1.SelectedIndex = 0 Then 'We will check for a zer index whcih would cause an exception.
            Exit Sub 'Exit the sub if there are no items to index
        Else
            Me.ListBox1.SelectedIndex = Me.ListBox1.SelectedIndex + 1 'Select next Item.
        End If
    Catch ex As Exception
        'You can handle your error here or ignore it. It's safe to ignore this one. ;)
    End Try
End Sub
Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox1.SelectedIndexChanged
    'When the index is changed, this will fire.
    'Put your code here to play next song.
End Sub