I have a TextBox by which if the user enters more than 10 characters it displays a MsgBox. That part works :D
The problem is the message also displays if the TextBox is empty and the user types the first character. I think thats because Null is seen as something greater than 10? but I'm not sure.
A) What is going on?
B) How can I fix this?
Private Sub TextBox3_KeyPress(sender As Object, e As KeyPressEventArgs) Handles TextBox3.KeyPress
If TextBox3.Text.Length >= 10 Then
MsgBox("WARNING")
End If
End Sub
You can try this. By using trim, white space characters is ignored. For an example, if the user only entered 10 [Spacebar] keys it will trim it out.
Private Sub TextBox3_KeyPress(sender As Object, e As KeyPressEventArgs) Handles TextBox3.KeyPress
If TextBox3.Text.Trim().Length() >= 10 Then
MsgBox("WARNING")
End If
End Sub
Related
I am looking for information on datagrid using textbox assign textchanged_event.
The problem I encountered was that when I typed the characters with a accented then datagrid would blink (it seems every change would be recorded in the textbox not just the final result).
Example: when typing "khang"
If I continue to type the letter "a", in english it will result in "khanga" and everything goes well, but in some languages it should be "khâng" and I see in textchanged it will take many steps as:
"khang" -> "khang•" -> "khang" -> "khan" -> "kha" -> "khâ" ->"khân"->"khâng"
in this moment, the datagrid will blink continuously.
what should I do to textchanged only handle the final result?
Thanks for advices!
You can't guarantee that you only handle the final value unless you use a Button.Click instead of a TextBox.TextChanged, or maybe force the user to hit Enter and handle the TextBox.KeyDown or the like. What you can do instead is ensure that you only act on the TextChanged if no other TextChanged has occurred for a specific length of time by using a Timer. That way, the delay is not so great that the user really feels it but it is long enough to allow multiple keystrokes without acting on them in between.
Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
'Start/restart the Timer every time the Text changes.
Timer1.Stop()
Timer1.Start()
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
'Perform filter when time expires.
Timer1.Stop()
BindingSource1.Filter = $"SomeColumn LIKE '%{TextBox1.Text}%'"
End Sub
It's up to you want you set the Interval of the Timer to but I'd be looking at around 300. You can do a bit of experimentation to find what gives you the best balance.
Is it possible to prevent entering characters that are already in the textbox?
like if I wrote in textbox
abcd
Then it is not allowed to write the same letters in it,
I searched and tried but could not find a way
All are about stopping letter gouging
It's pretty simple, just use the following code:
Private Sub TextBox1_KeyPress(sender As Object, e As KeyPressEventArgs) Handles TextBox1.KeyPress
e.Handled = TextBox1.Text.Contains(e.KeyChar)
End Sub
It'll help preventing typing the existing text(s) containing in a TextBox.
Hope it helps you!
I took an entry level computer programming class this past term and I'm having problems with my final project. I have to design a program in visual basic GUI that asks the player to accurately guess a number between 1-100 within a limited number of guesses.
My first form asks the user to set the number of guesses allowed. It has one textbox and an "enter" button, among other buttons that I've gotten to work.
I'm trying to get code to work that will validate the input on the guesses allowed. Specifically, I want a message box to pop up if the player enters letters or special characters instead of numbers, or enters a number less than zero, or greater than twenty. Here's what I have:
Public Class Noofguesses
Shared maxguesscnt As Integer
Private Sub Numberofguesses_TextChanged(sender As Object, e As EventArgs) Handles Numberofguesses.TextChanged
End Sub
Private Sub Quit_Click(sender As Object, e As EventArgs) Handles Quit.Click
End
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Form3.Show()
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If Val(Numberofguesses) > 20 Then MsgBox("Number of Guesses Cannot Exceed 20")
If Val(Numberofguesses) < 0 Then MsgBox("Number of Guesses Must Be Greater Than 0")
If Not IsNumeric(Numberofguesses) Then MsgBox("Entry Cannot be Letters or Characters")
Me.Close()
Form2.Show()
End Sub
End Class
What am I doing wrong? Please let me know.
Thanks
I would generally suggest using a NumericUpDown rather than a TextBox, in which case no validation is required. As this is an assignment though, I'm guessing that validating a TextBox is a requirement. In that case, you should use Integer.TryParse to validate a String, i.e. the Text of the TextBox and convert it if it is valid. You can then test the converted value to make sure that it isn't less than zero, etc. I'm not going to write the code for you, given that this is homework, but that should be enough for you to do it yourself or, if you feel you must, find examples online.
I need to send the keystroke combination INSERT + S keys simultaneously but it seems that VB only leaves use key combinations with ALT, CTRL and SHIFT.
Is there any way to do it?
I've tried:
{INS}(S)
{INS}S
and many others, but this does not work.
Thanks a lot.
It does. See:
https://msdn.microsoft.com/en-us/library/system.windows.forms.sendkeys%28v=vs.110%29.aspx?f=255&MSPPError=-2147217396
Had you tried "{INS}(S)" ?
UPDATE
I did the following test:
Private Sub TextBox1_Click(sender As Object, e As EventArgs) Handles TextBox1.Click
SendKeys.Send("{Ins}S")
End Sub
Private Sub TextBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyDown
MsgBox(e.KeyCode)
End Sub
Look, I received in the KeyDown event 2 codes: the INS and the "S"
The problem is about the KeyDown event will file TWO TIMES, I mean, you cannot get the INS-S code with ONE reading.
So, you must consider have a FRIEND/PUBLIC variable to receive both codes and only after this, make the critic about these.
Good luck
I have 6 textboxes that I want to use for password validation.
How can I:
limit the number of characters the user can enter into each password field to X-characters; and
ensure that text that are being entered into each field automatically flow into the next input field?
Thank you.
What platform are you using? Given your vb.net 2010 tag, I will assume it is a vb.net application you are working on?
If this is so, try this:
Private Sub TextBox1_TextChanged(sender As System.Object, e As System.EventArgs) Handles TextBox1.TextChanged
If Textbox1.Text.Length = X then
Textbox2.Focus()
End If
End Sub
The Focus() just takes the focus to the next Textbox control if the condition that the length of the text in Textbox1 equals your set "X" characters target.You can do this for all the textboxes you have on your form.
I hope this helps you.