I am new to vb.net and am trying to detect a KeyPress on a Form
I have accomplished this in JavaFX by creating a listener that when the ESC Key is press the application close
I have not found any code examples that use a listener in vb.net
I have found code that Handles a KeyPress for a TextBox but the same code for a Form FAILS
For this function to close the application from any Form I am wondering if it needs to be declared in a Module? While that part of the question would be nice to know Call it a Bonus
My question is why is this code not detecting a keypress on frmOne ?
The code to detect a keypress in the txtBoxOne runs as expected
Public Class frmOne
Private Sub frmOne_KeyPress(sender As Object, e As KeyPressEventArgs) Handles Me.KeyPress
'frmOne Property FixedToolWindow
'frmOne is the Start Up Form
If Asc(e.KeyChar) > 1 Then
MessageBox.Show("You Pressed " & e.KeyChar)
End If
'If Asc(e.KeyChar) > 1 Then txtBoxOne.Text = "You Pressed"
End Sub
Private Sub txtBoxOne_KeyPress(sender As Object, e As System.Windows.Forms.KeyPressEventArgs) Handles txtBoxOne.KeyPress
If Asc(e.KeyChar) = 13 Then
e.Handled = True
MsgBox("Error.")
Else
e.Handled = False
End If
End Sub
Private Sub btnToFormTwo_Click(sender As Object, e As EventArgs) Handles btnToFormTwo.Click
Dim i As Integer
i = txtBoxOne.Text.Length
If i = 0 Then
'txtBoxOne.Text = "Enter"
MessageBox.Show("Enter Data")
txtBoxOne.Select()
Return
End If
Dim OBJ As New frmTwo
OBJ.SPass = txtBoxOne.Text
OBJ.Show()
'MyTextBox_Enter()
txtBoxOne.Clear()
Me.Hide()
'Me.Close()'R Click project PassVar Set Start Up Form
'Best Solution is to have Splash Form as Start Up Form
End Sub
Public Sub MyTextBox_Enter()
txtBoxOne.Clear()
End Sub
'Private Sub frmOne_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'Use code below if pre populated text in txtBoxOne
'Me.ActiveControl = txtBoxOne
'txtBoxOne.Select(txtBoxOne.Text.Length, 0)
'txtBoxOne.Select()
'End Sub
End Class
The same code will work for a form but a form will not raise keyboard events by default if a child control has focus. You need to set the form's KeyPreview property to True, in which case the form will raise those keyboard events before the active child control does.
Related
Using VB.Net on a winforms application I have two forms
Both forms are set to "When Last Form Closes"
Both forms have "Key Preview" set to TRUE
frmOne the start up form has a "Form Border Style" set to FixedToolWindow
Here are the sequence of events preformed with the two forms
Load frmOne and click the X button on the title bar form closes and the start button shows up in the IDEThis is the desired behavior
Second sequence of events load app frmOne has a button to navigate to frmTwo and frmTwo has a button to navigate back to frmOne When we arrive back at frmOne we click the X button on the title bar and frmOne close but the app is still running NO Start button in the IDE
The Question is how to close the application after navigating to other forms?
The Code Below are the various ways I have tried to solve this issue
I am including the KeyPress Code which does not exhibit the desired results
Private Sub frmOne_KeyPress(sender As Object, e As KeyPressEventArgs) Handles Me.KeyPress
'frmOne Property KeyPreview needs to be set to True
If Asc(e.KeyChar) = 27 Then
'MessageBox.Show("You Pressed " & e.KeyChar)
Me.Close()
End If
End Sub
'Public Sub frmOne_QueryClose(Cancel As Integer, CloseMode As Integer)
'Prevent user from closing with the Close box in the title bar.
'If CloseMode = 1 Then Me.Close()
'If CloseMode = 1 Then Application.Exit()
'End Sub
'Private Sub frmOne_FormClosing(sender As Object, e As FormClosingEventArgs) 'Handles Me.FormClosing
'Application.Exit()
'Me.Close()
'End Sub
Private Sub frmOne_FormClosed(sender As Object, e As FormClosedEventArgs) Handles Me.FormClosed
'Application.Exit()
End Sub
Code to frmTwo
Private Sub btnToFormTwo_Click(sender As Object, e As EventArgs) Handles btnToFormTwo.Click
Dim i As Integer
i = txtBoxOne.Text.Length
If i = 0 Then
MsgBox("Enter Data")
txtBoxOne.Select()
Return
End If
Dim OBJ As New frmTwo
OBJ.SPass = txtBoxOne.Text
OBJ.Show()
lblFormOne.Text = " "
txtBoxOne.Clear()
Me.Hide()
'Me.Close()'R Click project PassVar Set Start Up Form
'Best Solution is to have Splash Form as Start Up Form
End Sub
Code Back to frmOne
Private Sub btnBack_Click(sender As Object, e As EventArgs) Handles btnBack.Click
frmOne.txtBoxOne.Text = "Back from 2"
Me.Hide()
frmOne.Show()
End Sub
You need to close Forms to get the application to end. I use "When last form closes" in a project with maybe a dozen forms and it works fine.
Private Sub btnBack_Click(sender As Object, e As EventArgs) Handles btnBack.Click
frmOne.txtBoxOne.Text = "Back from 2"
'Me.Hide() 'frmTwo is still running, To close a form use .Close()
Close()
frmOne.Show()
End Sub
You had your vb project set to quit "when last form closes" - opening a second form from your startup form meant that when you closed the startup form, there was still another form open so the app did not quit. Changing the setting to "when startup form closes" made the app behave as you expected
I have 10 buttons and I want to click on a button so it changes text of the focused textbox and switch to next textbox.
i tried this:
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
TextBox1.Focus()
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If TextBox1.Focus Then
TextBox1.Text = "1"
TextBox1.Enabled = False
TextBox2.Focus()
TextBox2.Enabled = True
End If
If TextBox2.Focus Then
TextBox2.Text = "1"
TextBox2.Enabled = False
TextBox3.Focus()
TextBox3.Enabled = True
End If
If TextBox3.Focus Then
TextBox3.Text = "1"
TextBox3.Enebled= False
TextBox4.Focus()
TextBox4.Enabled = True
End If
End Sub
But it writes the value in every textbox instead of just going to the next textboxt
This code does not do what you think it does:
If TextBox1.Focus Then
Focus is not a boolean property. In VB.Net, you can call methods without parentheses, and that's what you're doing here. The conditional block actually tries to set the focus. And since this is always gonna succeed unless you explicitly handle the event and block it, all of those If conditions result in True.
To find which control has focus, do this:
Public Shared Function FindFocusedControl(control As Control) As Control
Dim container = TryCast(control,IContainerControl)
While container IsNot Nothing
control = container.ActiveControl
container = TryCast(control, IContainerControl)
End While
Return control
End Function
In your Click event handler, you are calling the Focus method of each TextBox in turn and then populating them if it succeeds. It will succeed every time so you populate every TextBox.
I suspect that what you meant to do was test the Focused property rather than call the Focus method. That would make more sense because then it would only populate the TextBox that had focus. That is still flawed though, because the Button that you just clicked will have focus, so you won't actually populate any TextBox.
You have two main choices here. Firstly, you could use a custom Button control that will not take focus when it is clicked. That way, the TextBox that had focus when you clicked will still have focus. Alternatively, you could remember which control last had focus by assigning it to a field and using that. That's probably the way that I'd go.
Here's a quick (i.e. not rigorous) example of the second option:
Private lastActiveControl As Control
Private Sub TextBoxes_Leave(sender As Object, e As EventArgs) Handles TextBox4.Leave,
TextBox3.Leave,
TextBox2.Leave,
TextBox1.Leave
lastActiveControl = DirectCast(sender, Control)
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim textBoxes = New Control() {TextBox1, TextBox2, TextBox3, TextBox4}
Dim lastTextBoxIndex = Array.IndexOf(textBoxes, lastActiveControl)
If lastTextBoxIndex <> -1 Then
Dim nextTextBoxIndex = (lastTextBoxIndex + 1) Mod textBoxes.Length
Dim nextTextBox = textBoxes(nextTextBoxIndex)
lastActiveControl.Text = "1"
lastActiveControl.Enabled = False
nextTextBox.Enabled = True
nextTextBox.Select()
End If
End Sub
I Want to say sorry if there was a same question like i had. I have tried to Search but i couldn't find it, so.. i hope there is no other question like this..
To the point, i need your help to tell me how to change the Location of an object in a form
What i want to do is making the Button1 move to the left when i press the left key on the keyboard. But i have a problem with how to set the location (x,y) of the object
Private Sub Button1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Button1.KeyPress
If Asc(e.KeyChar) = Keys.Left Then
End If
End Sub
Thanks ...
By default, the arrow keys are not captured by the control's KeyPress, KeyDown or KeyUp events. You can make them be captured by KeyDown and KeyUp by setting e.IsInputKey to True in the PreviewKeyDown event. Then you can move the button sideways by changing its Left property. The following assumes the button has focus.
Private Sub Button1_PreviewKeyDown(sender As Object, e As PreviewKeyDownEventArgs) _
Handles Button1.PreviewKeyDown
If e.KeyCode = Keys.Left Or e.KeyCode = Keys.Right Then e.IsInputKey = True
End Sub
Private Sub Button1_KeyDown(sender As Object, e As KeyEventArgs) _
Handles Button1.KeyDown
Dim myButton As Button = CType(sender, Button)
If e.KeyCode = Keys.Left Then myButton.Left -= 1
If e.KeyCode = Keys.Right Then myButton.Left += 1
End Sub
Updated Solution
Here's a way to accomplish it so that it moves while holding down the key. Create a project with a Form and Button.
Right-click on the Project in the Solution Explorer and add two .NET References:
PresentationCore
WindowsBase
Here's the code. A timer will capture key events and move the button:
Imports System.Windows.Input
Public Class Form1
Private timex As New Timer
Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
AddHandler timex.Tick, AddressOf myTickEvent
timex.Enabled = True
timex.Interval = 100
End Sub
Private Sub myTickEvent(sender As Object, e As EventArgs)
If isKeyPressed(Key.Left) Then
Me.Button1.Left -= 10
End If
If isKeyPressed(Key.Right) Then
Me.Button1.Left += 10
End If
If isKeyPressed(Key.Up) Then
Me.Button1.Top -= 10
End If
If isKeyPressed(Key.Down) Then
Me.Button1.Top += 10
End If
End Sub
Private Function isKeyPressed(ByRef keys As System.Windows.Input.Key)
If (Windows.Input.Keyboard.GetKeyStates(keys) And Windows.Input.KeyStates.Down) > 0 Then
Return True
Else
Return False
End If
End Function
End Class
As I'm putting the finishing touches on my program I'm having some troubles.
Theres several user inputs and a submit button, once the inputs has been filled I wish to enable the submit button, else the button should be disabled. This is what I have:
Private Sub ButtonControl(sender As System.Object, e As System.EventArgs) Handles Input1.Validated
If Input1.Text = "" Then
ButtonSubmit.Enabled = False
ElseIf Input1.Text <> "" Then
ButtonSubmit.Enabled = True
End If
End Sub
The thing is it disables nomatter what and then it doesnt enable when my input is filed
Your code will work if you have another control that can receive the focus. Control Validation occurs on the loss of focus. If you need to have just one focusable item active you will need to use either KeyPress, KeyDown or Textchanged events to enable your button, also make sure that the CausesValidation property of your TextBox is true.
I would also make the method more generic so you could call it from multiple textbox's by using the sender object to access the textbox that raised the event. Also if you have a True/False condition you only need to do the comparison in the first if statement and then you just use an else not an elseif.
for example:
Private Sub ButtonControl(sender As System.Object, e As System.EventArgs) Handles Input1.Validated
If DirectCast(sender, TextBox).Text = "" Then
ButtonSubmit.Enabled = False
Else
ButtonSubmit.Enabled = True
End If
End Sub
You can also use the String.IsNullOrWhiteSpace Method to check if just spaces have been entered if you are using the 4.0 framework or above. Like this TextChanged EventHandler.
Private Sub ButtonControl(sender As Object, e As EventArgs) Handles Input1.TextChanged
If String.IsNullOrWhiteSpace(DirectCast(sender, TextBox).Text) Then
ButtonSubmit.Enabled = False
Else
ButtonSubmit.Enabled = True
End If
End Sub
You are going to need to use the TextBox "TextChanged" event, and be sure to set each Textbox AutoPostback="True". You can use an UpdatePanel to make the postbacks that occur on each Textbox you wish to validate less obnoxious to your end-user.
So, your textbox (if you have many, make sure they all have the OnTextChanged="ValidateForm":
<asp:TextBox ID="Input1" runat="server" OnTextChanged="Validate_TextChanged" />
Inside your textchanged ("ValidateForm") event (which each Textbox is attached to), one quick to implement route to do would just be
' Validation inside this event
Protected Sub Validate_TextChanged(sender As Object, e As EventArgs)
if Input1.text <> "" AndAlso Input2.text <> "" AndAlso ' ...etc.
End Sub
If you go the route of the UpdatePanel, you may find this useful.
This is the kind of thing I would do:
Private Sub TextBoxes_TextChanged( _
ByVal sender As System.Object, ByVal e As System.EventArgs) _
Handles _
TextBox1.TextChanged, _
TextBox2.TextChanged, _
TextBox3.TextChanged
Dim textBoxes = { TextBox1, TextBox2, TextBox3 }
Button1.Enabled = textBoxes.All(Function (tb) tb.Text <> "")
End Sub
You can then add as many text boxes in to the textBoxes array as you need to check. Just make sure that the text boxes to the Handles list.
Private Sub TextBox1_TextChanged(sender As System.Object, e As System.EventArgs) Handles TextBox1.TextChanged
If TextBox1.Text.Length > 0 Then
Me.Button1.Enabled = True
Else
Me.Button1.Enabled = False
End If
End Sub
Do that code in the Input1_TextChanged event
This is what I did and worked:
Dim CheckInput1 As Boolean
Private Sub Input1_TextChanged(sender As Object, e As EventArgs) Handles Input1.TextChanged, Input1.Enter
CheckInput1 = True
If Input1.Text = "" Then
CheckInput1 = False
End If
If CheckInput1 = False Then
ButtonSubmit.Enabled = False
ElseIf CheckInput1 = True Then
ButtonSubmit.Enabled = True
End If
End Sub
There must be a more efficient code that this but I think this solves your problem.
I'm working on VS 2010 with VB using .NET Framework 4.0
I have a combobox. It has some items in it and displays just fine. Here's where it gets a little weird:
If I click the drop-down arrow on the combobox and CLICK on the item I want, SelectedIndexChanged is called - good.
If I click inside the text area of the combobox and start typing what I want selected and finish it by pressing the up (or down) key, SelectedIndexChanged is called - also good.
If I click the drop-down arrow on the combobox and start typing what I want selected and finish it by pressing ENTER, SelectedIndexChanged is not called - PROBLEM.
Is there a different event that is caused by the ENTER in the last case? I've tried using the TextChanged and TextUpdate events, but those do not seem to be working:
Private Sub cmbStatus_TextChanged(sender As System.Object, e As System.EventArgs) Handles cmbStatus.TextChanged
If e.Equals(Keys.Enter) Then
Call SomeMethod()
End If
Should I use something besides e.Equals(Keys.Enter)?
Is there another event I should be looking for?
EDIT:
An example of the items in the ComboBox are:
10 - NEW ENTRY AND COMPLETENESS CHECK ---> this is the most common type
13 - ASSIGNED TO TRB/HRB ---> there are a few with '/'
60 - EXTERNAL (HOLD UNTIL FURTHER NOTICE) ---> there are a few with '(' and ')'
Basically, the type of each listing is "## - SOME TEXT".
Disclaimer: this is written in C# - let me know if you need it translated to VB.
private void comboBox1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
//It's important to also check that the Combo Box is displaying its Drop Down. If
//you want this to execute even when it is not displayed, remove the check for
//comboBox1.DroppedDown.
if (e.KeyCode == Keys.Enter && comboBox1.DroppedDown &&
!string.IsNullOrEmpty(comboBox1.Text))
{
int index;
//Attempt to locate the string typed in by the user. An index of -1
//means it was not found.
if ((index = comboBox1.FindStringExact(comboBox1.Text)) != -1)
{
//Update the SelectedIndex.
comboBox1.SelectedIndex = index;
}
}
}
Interestingly, the docs say that we should be using the SelectionChangeCommitted event instead of the SelectedIndexChanged event when handling selection changes made by the user. It is necessary to do so in this case as the SelectedIndexChanged event fires twice using my approach.
Edit:
To prevent the user from having to type the entire string, use the advice from Adi's answer: go to the properties of the combo box and set set AutoCompleteMode to SuggestAppend and AutoCompleteSource to ListItems - I actully used these settings when creating my answer, so it should work for you.
Option Strict On
Public Class Form1
Friend WithEvents ComboBox1 As New ComboBox With {.Parent = Me}
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
ComboBox1.Items.AddRange({"hello", "tes1ted", "word", "item", "tes2ted"})
ComboBox1.Text = ComboBox1.Items(0).ToString
End Sub
Private Sub ComboBox1_KeyUp(ByVal sender As Object, ByVal e As KeyEventArgs) Handles ComboBox1.KeyUp
'You can put this in the keydown event, or adapt it a small bit and put it in the keypress event
'putting it in the textchanged event is problematic and not recommended.
Dim OriginalText As String = ComboBox1.Text
If e.KeyCode = Keys.Enter Then
If ComboBox1.SelectionLength > 0 Then
ComboBox1.Text = ComboBox1.Text
ComboBox1.SelectionLength = 0
ComboBox1.SelectionStart = ComboBox1.Text.Length
End If
End If
If Not IsTextKey(e.KeyCode) Then Exit Sub
Dim Filter As String = ComboBox1.Text & "*"
If Filter.Length = 1 Then Exit Sub
For I = 0 To ComboBox1.Items.Count - 1
If LCase(ComboBox1.Items(I).ToString) Like LCase(Filter) Then
ComboBox1.SelectedItem = ComboBox1.Items(I)
ComboBox1.Select(OriginalText.Length, (ComboBox1.Text.Length - OriginalText.Length))
Exit Sub
End If
Next
End Sub
Function IsTextKey(ByVal Key As Integer) As Boolean
Select Case True
Case Key = Keys.Up : Return False
Case Key = Keys.Down : Return False
Case Key = Keys.Left : Return False
Case Key = Keys.Right : Return False
Case Key = Keys.Back : Return False
Case Key = Keys.Delete : Return False
Case Key = Keys.LWin : Return False
Case Key = Keys.RWin : Return False
'add whatever I missed
'return false if the key either removes text from the textbox
'or does not produce a character
Case Else
'return true if the key produces a visible character(including space)
Return True
End Select
End Function
End Class
Private Sub ComboBox1_KeyUp(sender As System.Object, e As System.Windows.Forms.KeyEventArgs) Handles ComboBox1.KeyUp
If e.KeyCode = Keys.Enter Then
MessageBox.Show(ComboBox1.SelectedText)
Call SomeMethod()
End If
End Sub
I believe that you should set AutoCompleteMode to SuggestAppend and AutoCompleteSource to ListItems. This way, if what you type in is sustainable with the items loaded in the ComboBox, by writing it down and finding that item, when pressed Enter, the SelectedIndexChanged will be fired (even if a match wouldn't be found - the first in the list will be selected)
I've prepared something to point out this to you.
Regards,
Adi Konstantin
Subscribe to the KeyPressed event:
Private Sub yourComboBox_KeyPressed(sender As System.Object, e As System.KeyPressedEventArgs) Handles yourComboBox.KeyPressed
If e.KeyChar.Equals((char)Keys.Enter) Then
Call SomeMethod()
End If
this will helps your problems
Private Sub ComboBox1_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles ComboBox1.KeyDown
If e.KeyCode = Keys.Enter Then
MsgBox("hello")'call some functions
End If
End Sub
Can you let me know if this works for you?
Private Sub ComboBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles ComboBox1.KeyPress
If e.KeyChar = Chr(13) Then
ComboBox1_SelectedIndexChanged(sender, e)
End If
End Sub
Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
MsgBox(ComboBox1.Text)
'Your code here
End Sub
I had a similar problem when the combobox dropdownstyle was set to simple with autocomplete set to append, sourcing from my listitems. My workaround was to have a string variable save the combobox text upon each textchanged event. That way, when ENTER is pressed, you can retrieve the deleted text and reassign it to the combobox text.
'Global declaration
'Global declaraion
dim selected_text as string = ""
Private Sub combobox_textchanged(sender As Object, e As EventArgs) Handles combobox.TextChanged
If combobox.Text IsNot Nothing And combobox.Text <> "" Then
selected_text = combobox.Text
End If
End Sub
Private Sub combobox_keydown(sender As Object, e As KeyEventArgs) Handles combobox.KeyDown
If e.KeyCode = Keys.Enter Then
combobox.Text = selected_text
'put logic here
End If
End Sub
There are some great answers above, but I liked that I didn't need to sort out all the command keys and arrows etc.
Close the list manualy on PreviewKeyDown event:
Private Sub cmbStatus_PreviewKeyDown(sender As ComboBox, e As PreviewKeyDownEventArgs) Handles cmbStatus.PreviewKeyDown
If e.KeyCode = Keys.Enter Then sender.DroppedDown = False
End Sub