Detect / Suppress Invalid Characters In TextBox?
Jan 5, 2012
I have a TextBox with a list of filenames in it. The user is able to change these file names, but I don't want them to enter invalid characters, such as slashes or question marks.
I've tried two approaches, but they are not satisfactory:
1. Detect the key pressed with the KeyDown event:
Use e.KeyValue to detect keys like Keys.Oem5 (= backslash), then use 'e.SuppressKeyPress = True' to suppress the key.Problem is, with different Keyboard layouts, The Oem5-key isn't always a backslash.
2. Filter the text:
Use the TextChanged event and do a Replace("", "") on the text for every invalid character (there's 9 of them).Of course this will create 'lag' with every keystroke, especially if there's a lot of text. Also the text-cursor and scrollbar will jump back to the top-left when using Replace.
In short: I'm looking for a way to detect the character that is being entered and suppress or remove it when invalid.
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Mar 27, 2010
I'm writing a program and it's got a textbox for the user to enter values. Since the textbox text property should only be a "number", my program need to detect invalid charaters like "*/&()$" and tell the user to only enter a number. Does anyone have an idea how to do that?
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Apr 24, 2010
i have an application of developed by .Net, i can use it my computer and other pc but only in one pc it isnt working and it give an error message "Invalid characters found in mail header" operatins system is Windiws 7
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Jun 10, 2010
I am developing an test application to read the data coming on serial port sent by the pabx. It is working fine. But, for some reason , i don't know why, some invalid characters are coming in the data, something like '?'
[Code]...
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Nov 17, 2009
Well I've recently discovered that trying to create a file with so-called 'illegal characters' will cause your application to crash.. How do I find these characters in a string and replace them with nothing?
The invalid characters are / : * ? " < > | if that helps.
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Apr 11, 2009
I am using a Balloon tooltip to show the user which characters are invalid as a filename. I use the IO.Path.GetInvalidFileNameChars array and convert each character to a string, before appending it to a "Invalid filename characters:" string.
vb.net
If IO.Path.GetInvalidFileNameChars.Contains(e.KeyChar) Then
e.Handled = True
Dim str As String = "The following characters are invalid filename characters:" & nl
Dim invalidChars As New List(Of String)
For Each c As Char In IO.Path.GetInvalidFileNameChars
[Code] .....
The result is not pretty: How do I get rid of the 'non-visual' characters (they are probably newlines, backspaces, null chars, etc) so they don't clutter up the list?
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Dec 4, 2010
I have menu item, in which I have specified ShortCutKeys as "Del". On click of menu item I have called specific method. I have one form on which one textbox is placed. When I hit the "Del" key the same method which gets called on menu item click is fired. I want the default behaviour to be followed by the textbox. how to suppress the event to be fired and to achive the default behaviour of the textbox or other controls present on the form.
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Dec 21, 2011
Essentially I am trying to replicate the Windows 7 (In-Windows) activation key TextBox form. The Form where it will auto capitalize letters, remove or deny all non alphanumeric characters except dashes every 5 characters that will be auto-input.I assume this can be done with a fairly complicated replacement Regular Expression but I cannot seem to create one to fit the needs.
This is an Example of what I have right now, but it creates an infinite loop as it removes all characters including dashes, than adds a dash, which changes the text and removes the dash again.
[Code]...
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Aug 5, 2011
I have two textboxes. I type in one of them and the text gets copied in real time into another textbox. There is one catch. I need to replace specific character with something else.
If I enter a quote " in textbox1, it has to be replaced with " in textbox2.
I started with something like the below code, but obviously this does not work (tried different stuff - this is for demonstration only). In the example below 'a' represents " , and 'b' represents "
Private Sub TextBox1_KeyUp(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.KeyUp
TextBox2.Text = TextBox1.Text
[Code]....
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Jul 15, 2010
I'm just wondering if there is a method in .NET 2.0 that checks whether a character is printable or not - something like isprint(int) from standard C.
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Dec 13, 2010
I wanna type 140 characters in asp.net textbox with multiline when i type in textbox then the characters will be decreaded means if i type two characters in textbox then in label the available characters will be shown is 138..using vb.net
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Mar 6, 2011
I have a ComboBox with
ComboBox1.AutoCompleteMode =
AutoCompleteMode.SuggestAppend
ComboBox1.AutoCompleteSource =
AutoCompleteSource.ListItems
How do you prevent a user from typing characters that are not in the list of options?If the list in the Combo is for example
aaa
abc
acd
How do you stop the user typing ad?
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Dec 30, 2009
On one of my projects, when I try to run it, I get a "Invalid command line switch for "AL.exe". Illegal characters in path." error. I have installed the "Windows SDK for Windows Server 2008 and .NET Framework 3.5," and this error is after installing it.
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Dec 13, 2011
how can I detect if press Enter in the Textbox Change event and not in Textbox Keypress?
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Aug 7, 2009
textbox1.text = "6916092, 15195440, 16107657, 1836924, 3758726, 12566463, 7526079, 7405793, 6945974, 241502, 2296476, 5130294, 3102017, 7324121, 14993507"
ColorDialog1.CustomColors = New Integer() {TextBox1.Text}
I am getting an InvalidCastException. How do I insert the value of textbox1.text into those brackets in vb.net?
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Aug 7, 2009
why do i get an error here?TextBox1.Text = TextBox1.Text & Str(ColorDialog1.Color)
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Oct 10, 2011
I've got a masked text box that throws an invalid cast exception if I try to put anything in the TextChanged event:
Private Sub mtbZVal_TextChanged(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MaskInputRejectedEventArgs) Handles mtbZVal.TextChanged
MsgBox("OK!")
End Sub
Even more oddly, it throws the exception in a completely different part of the program. The masked textbox is on a form that opens when you press a button, and that's the bit that gives the error:
Private Sub cmdAddLoc_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdAddLoc.Click
If frmLocation.ShowDialog() = DialogResult.OK Then
End If
End Sub
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Nov 3, 2011
My console errors out when I enter anything other than a number or operators in the designated (input). I stink at this stuff but I have been t this for about 8 hrs. still not there. I have included a text file for the task at hand
[Code]...
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Jul 15, 2009
I'm using WMI code and VB 2008 to see NIC status. So far the queries are working, but the methods aren't. For example, I'm trying to set a network card to use DHCP, I get invalid function with this code:
Dim classInstance As New ManagementObject("rootCIMV2", "Win32_NetworkAdapterConfiguration.Index='7'", Nothing)
Dim outParams As ManagementBaseObject = classInstance.InvokeMethod("EnableDHCP", Nothing, Nothing)
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May 7, 2012
The Textbox_TextChanged event fires when a key is pressed or when text is pasted while cursor is in a text box.
Is there an event that fires on Textbox1.text="NewText"? How do I detect this?My reason for doing this is I would like to reformat text property automatically on assignment rather than do something like textbox.text=myreformat("Newtext").I can put code in validating or validated event but then I'd have to force focus/lostfocus to trigger one of those events.
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May 11, 2010
I'm using VB Express 2008 and I want tto write a simple code.
[Code]...
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Nov 19, 2010
I am new to Visual Basic and i am using VS 2008. I have a form with multiple (7) text boxes. What i would like to accomplish is basically, when i click on textbox 1 a predefined message would load to label1 and when i click on textbox2 label1 would now displays a different pre-defined message and etc... I've tried using the "focus" parameter of the textbox but it doesn't work. So i am thinking of using the cursor as a way to solve my problem but i don't know how to work with it. I found a very similar thread titled " Detect when the cursor is in a textbox/typing in webbrowser?" on this forum but i don't think it applies to my situation.
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Apr 3, 2011
there any way that i can always have a / as the first character in the textbox?
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Aug 17, 2011
Using VB2008.We have copied a file into a textbox for editing.It is not allowed to delete certain characters, for example the $.
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Aug 17, 2011
We have copied a file into a textbox for editing.It is not allowed to delete certain characters, for example the $.
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Feb 17, 2011
I am trying to show the square root of the number entered in the textbox. when the user presses Q (Uppercase), the square Root should be shown (in the textbox). I did manage to get the sqaure root, but the problem is that when I press Q the Letter Q is also typed in. For example, if I enter 25 in the textbox and press Q then I get Q5 as the result. Is there any work around to this problem ? Below is the code that I have used.
Private Sub Textbox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
If e.KeyChar = Chr(81) Then '81 for Letter Q
Dim root As Double = Math.Sqrt(Val(TextBox1.Text))
[code]....
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Jun 8, 2011
I wanted to set a maximum limit of characters of textbox in the properties but i can't find where it is located unlike in vb 6.0 you can set the characters in maxlength...
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Oct 30, 2011
I have a a multiline textbox, I want to take each and every character that the user enters and on a button press it replaces them with a set of characters, like:
i with x75d
or:
f with g8r
but the only way i have figured out how to do something like this is using a character in between each character and the split method, like:
Dim input() As String
Dim txt as String
Private Sub Encode_Click(ByVal sender As System.Object, ByVal e As
[Code]....
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Sep 4, 2009
i would like to limit a textbox input to 20 characters and only one line to input the characters.. i really have no idea where to start. i did see some forum threads, except they're for different options other than the option i need.. trujade.so much work to do and so many choices to choose from...
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Nov 25, 2009
I have a textbox that is for National Insurance Number, so I want the first 6 characters to be letters and the last to be a number. I know I need to use the Is Numeric function but I cannot get it to work.
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