Currently I have the start-key for my vb.net application hardcoded like this:
GetAsyncKeyState(Keys.F2)
Where vb.net sais "F2 As System.Windows.Forms.Keys = 113" on mouse-over
But I want my users to be able to pick their own Key. If I make a drop-down box (combobox) and pre-define some choices in there (Like ESC or F3), all those choices are strings. How can I convert those strings to a System.Windows.Forms.Keys integer?
Also, I'd like it to also be possible to "capture" a single keypress. So they'd click the "capture" button, and the next key they hit will be saved as the start/stop button. But I wouldn't even know where to begin looking for that one.
If txtKeys.Text=="F3" Then
GetAsyncKeyState(Keys.F3)
End If
Try something like this:
Public Class Form1
Dim captureKey As Boolean
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
captureKey = True
End Sub
Private Sub Button1_PreviewKeyDown(sender As Object, e As System.Windows.Forms.PreviewKeyDownEventArgs) Handles Button1.PreviewKeyDown
If captureKey Then
Label1.Text = e.KeyValue.ToString
captureKey = False
End If
End Sub
End Class
I created a form with a label and a button for an example. e.KeyValue is an integer that I am converting to a string for display purposes. You also have the ability to capture other keydata. See this info on PreviewKeyDownEventArg
As for the first part of your question use a Select Case Statement to convert between your ComboBox Values and KeyData Values.
Related
Good day!
I want to add some strings from a barcode scanner, captured in a text box, to a list box, and, before adding it, to check if the specific string hasn't been already added. So I have a text box called txtWO which captures what the reader scans and a list box called lstScanBOM to which I add the text box string if the item is not already added. The problem is, that whatever I do, only after the specific string is added twice the checking for duplicate entry starts to work. In other words I scan the same string twice, it added it, and then when I scan the third time only it throws the message with the error saying it is a duplicate. I don't understand why is doing this. The code is below:
Private Sub frmValidareFIP_Load(sender As Object, e As EventArgs) Handles MyBase.Load
If txtWO.Focused = False Then
txtWO.Select()
End If
End Sub
Private Sub AddUnique(StringToAdd As String)
If lstScanBom.Items.Contains(StringToAdd) = True Then
MsgBox("Articol duplicat!", vbOKOnly)
Else
'it does not exist, so add it..
lstScanBom.Items.Add(StringToAdd)
End If
End Sub
Private Sub txtWO_KeyDown(ByVal sender As Object,ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtWO.KeyDown
If e.KeyCode = Keys.Enter Then
Dim barcode As String
barcode = txtWO.Text
AddUnique(barcode)
txtWO.Clear()
txtWO.Focus()
End If
End Sub
IMO Try listing the data outside of the ListBox. I can't see why it isn't working, maybe we need a third pair of eyes to see it!?
Try adding a list (of string) as a Private within the form, populate this as your user scans, and check the duplicate there..
This is definately not the best solution, but I'm sure it will help!
Private List_Barcodes As List(Of String)
Private Sub frmValidareFIP_Load(sender As Object, e As EventArgs) Handles MyBase.Load
List_Barcodes = New List(Of String)
'You can also populate this list on load, if you have a stored cahce of previous scanned barcodes?
'List_Barcodes.Add("0123456")
'List_Barcodes.Add("4567890")
'...etc
If txtWO.Focused = False Then
txtWO.Select()
End If
End Sub
Private Sub AddUnique(StringToAdd As String)
If List_Barcodes.Contains(StringToAdd) Then
MsgBox("Articol duplicat!", vbOKOnly)
Else
'Place into dynamic list
List_Barcodes.Add(StringToAdd)
'and Place into your listbox
lstScanBom.Items.Add(StringToAdd)
End If
End Sub
Private Sub txtWO_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtWO.KeyDown
If e.KeyCode = Keys.Enter Then
Dim barcode As String
barcode = txtWO.Text
AddUnique(barcode)
txtWO.Clear()
txtWO.Focus()
End If
End Sub
Your barcode reader is returning <carriage return><line feed> as enter. Your code catches the enter key (carriage return = 13), but leaves the line feed (10) character. So the next time you scan something it will start with a line feed. The two strings in your example are different because the first is "58335001" and the second is "<line feed>58335001". The third one is "<line feed>58335001", which is a duplicate of the second.
One way to fix this is to trim your string.
Private Sub txtWO_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtWO.KeyDown
If e.KeyCode = Keys.Enter Then
Dim barcode As String
'Add the .Trim() to remove the leading <line feed> character
barcode = txtWO.Text.Trim()
AddUnique(barcode)
txtWO.Clear()
txtWO.Focus()
End If
End Sub
The most simple decision is ONLY to make your textBox control txtWO NOT multiline
And that's enough! Your code will work correctly!
I need to set a minimum length for a password that can be used in a textbox and then set a label which will say if it meets the minimum number of characters required. I know how to set the limit of characters, what I can't do is the part where it will show in a label as soon as I leave the textbox. I was thinking I need to use an event, like maybe Leave or LostFocus, but it's not working. Please help :(
Ok, There are plenty of ways to do what you want to achieve. I personally like to a separate subroutine; if you need to change one thing, you wont have to edit every single event that has the same codeFrom what I can understand, something like this should help get you on your way. Basically, we just setup a subroutine that will check to see if textbox1.text's length is more than five and we trigger the subroutine by using events such as a button click of if the textbox is clicked off.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click ''save button
checkPassword(TextBox1.Text)
End Sub
Private Sub TextBox1_Leave(sender As Object, e As EventArgs) Handles TextBox1.Leave
checkPassword(TextBox1.Text)
End Sub
Private Sub checkPassword(password As String)
If Not password.Length > 5 Then
Label1.Text = "The password must be more than 5 charcharacters"
TextBox1.Clear()
Else
Label1.Text = "Password accepted"
End If
End Sub
I'm making a program which requires a login system. What I want to do is have a textbox which contains the word 'Username' and when the user clicks it, the 'Username' text is overwritten. For example, Spotify use it on their login screen:
My question is, how do I do this?
Set the Text property of the TextBox that you are using for the username to the string "Username". Then, in the TextBox's Click event, change it to a blank string. Like so:
Private Sub TextBox1_Click(sender As Object, e As EventArgs) Handles TextBox1.Click
TextBox1.Text = ""
End Sub
Edit:
As #LarsTech mentioned, this does not address if the user tabs into the TextBox. If you wanted to account for that too, use the TextBox's Enter event instead:
Private Sub TextBox1_Enter(sender As Object, e As EventArgs) Handles TextBox1.Enter
TextBox1.Text = ""
End Sub
I agree, using Textbox1.Enter is the easiest solution. On top you can also catch the case of no text entered via TextBox1.Leave like that
Private Sub TextBoxLeaveHandle() Handles TextBox1.Leave
If TextBox1.Text = "" Then
TextBox1.Text = "Username"
End If
End Sub
Sometimes it can also be useful to use the TextBox.SelectAll() function as it not immediately remove the entire text but (obviously from the name) select the entire text so you can overwrite it with your first keypress.
using VB.net and Visual studio is there a way to globally (across all fields in all forms in a project) prevent a user from entering a single quote character into a field. I'm thinking some sort of modification of the keypress event, but I'm not sure how to go about it. Currently I am currently using the ADDHANDLER, ADDRESSOF technique to assign this special code to a particular field, and I guess I could do a loop over all my contained controls on a particular form and assign the keypress code, but if there is a way to do it once without repeating the code on each form that would be great. Any hints graciously accepted. Thanks.
What about a regex? Stripping or converting to escape character on submit?
Would it be possible to pass an array where TextBox1 is TextBox1,Textbox2, etc. Obviously you would need to edit the expression if you only need to strip the single quote. This for all non alphabet characters. I don't do much with vb.net but thought this might be helpful.
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
StripNonAlphabetCharacters(TextBox1)
End Sub
Public Sub StripNonAlphabetCharacters(ByVal input As TextBox)
' pattern matches any character that is NOT A-Z (allows upper and lower case alphabets)
Dim rx As New Regex("[^a-zA-Z]")
If (rx.IsMatch(input.Text)) Then
Dim startPosition As Integer = input.SelectionStart - 1
input.Text = rx.Replace(input.Text, "")
input.SelectionStart = startPosition
End If
End Sub
The easiest solution is to create a derived TextBox and use that instead of the standard textbox.
Public Class NoQuoteTextBox
Inherits TextBox
Public Sub New()
AddHandler MyBase.KeyPress, AddressOf Handler
End Sub
Public Sub Handler(ByVal sender As Object, ByVal e As KeyPressEventArgs)
If e.KeyChar = "'" Then
e.Handled = True
End If
End Sub
End Class
Build your project then the NoQuoteTextBox (or whatever you decide to call it) will appear in the Toolbox in the Designer:
Use this new control instead of the standard textbox and it will handle the single quote for you.
I have a TextBox, which has a CheckBox operation to mask the containing text. This works with the following code:
Private Sub CheckBox2_Checked(ByVal sender As Object, ByVal e As EventArgs) Handles CheckBox2.CheckedChanged
TextBox14.PasswordChar = "*"
End Sub
It works well, but I want to also be able to uncheck theCheckBox and then have the recognizable text return. How can I achieve this?
The docos actually state:
The character used to mask characters entered in a single-line TextBox
control. Set the value of this property to 0 (character value) if you
do not want the control to mask characters as they are typed. Equals 0
(character value) by default.
Found here: http://msdn.microsoft.com/en-us/library/system.windows.forms.textbox.passwordchar(v=vs.110).aspx
In VB.NET, that would be easiest done by setting PasswordChar to vbNullChar.
You can do so by simply setting the PasswordChar property back to a null character, like this:
Private Sub CheckBox2_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs) Handles CheckBox2.CheckedChanged
If CheckBox2.Checked Then
TextBox14.PasswordChar = "*"c
Else
TextBox14.PasswordChar = ControlChars.NullChar
End If
End Sub
The CheckedChanged event occurs every time the Checked property changes. So, when the user unchecks the CheckBox, it will raise that event too, so you need to check to see whether or not the control is currently checked.
I found just toggling the password character wasn't enough. In my case I was masking a connection string. With the lack of spaces in my text I had an issue going back and forth. My text would be cut off and wasn't wrapping properly.
Private Sub CheckBox1_CheckedChanged(sender As Object, e As EventArgs)
Dim beforeText As String = TextBox1.Text
TextBox1.Text = ""
TextBox1.PasswordChar = IIf(CheckBox1.Checked, Convert.ToChar(0), "*"c)
TextBox1.Text = beforeText
End Sub
I imagine if you used a font like Console this would not be a problem as all character widths are constant.