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problem with text boxes RRS feed

  • Question

  •  

    hi!

     

    is there anyone out there who knows how to make the output of a text box into an integer?

     

    I am attempting to create a form of calculator that factors trinomials and I need the text boxes to have integer output.

    In other words I want [txtb.text] to be an integer, not a string as I cannot do mathematical operations on strings.

     

    a coding sample follows

     

    I want to be able to do this:

     

    int  intvar = txtb.text

     

    but I can only do this at present:

     

    string  intvar = txtb.text

     

    hope someone can help!

    Tuesday, September 18, 2007 8:58 PM

Answers

  • Try: intVar = CInt(txtb.text)

    Hope that works for you Smile

    Tuesday, September 18, 2007 9:05 PM
  • Another method:

     

    Intvar as integer = Integer.Parse("1234")

     

    You may also want to add error handling unless you've restricted the textbox entry to just numbers.

     

    Tuesday, September 18, 2007 9:26 PM
  • Hi Darth,

     

    Based on your post, you need to restrict the textbox entry to just numbers. Here are many methods. Using the regular expression is one easy method to achieve this. For more information about learning the regular expression, please visit:

    this article ”The 30 Minute Regex Tutorial” By Jim Hollenhorst in the codeproject. When you convert the digit string to integer type, you need to add the error handling. For more information about error handling and throwing exception, please visit: http://msdn2.microsoft.com/en-us/library/5b2yeyab.aspx. Here is the code snippet about how to restrict the textbox entry just numbers.

    Code Snippet

    Dim rxImageCode As Regex = New Regex("(\d+)")

    Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged

    Dim rxMatch As Match = rxImageCode.Match(Me.TextBox1.Text)

    If (rxMatch.Success) Then

    TextBox1.Text = rxMatch.Groups(0).Value

    End If

    End Sub

     

     

     

    Best regards.
    Thursday, September 20, 2007 10:39 AM
    Moderator
  • First of all, ALL input into the computer is done with strings, including textboxes. In order to process the string data mathematically, it must be converted into a number type.  Then, to display the results, the numeric data must be converted back into a string.

     

    To restrict input to integers in a textbox while user enters data from the keyboard, use the following code.

     

    If you want only a positive integer, place this code in the textbox's Keypress event. It will not accept any key other than the digits from 0 to 9, but it will accept the backspace key. The Enter key may be used to move to the next control.

     

    Code Snippet

    Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress

    If Not Char.IsDigit(e.KeyChar) Then e.Handled = True

    If e.KeyChar = Chr(8) Then e.Handled = False 'allow Backspace

    If e.KeyChar = Chr(13) Then TextBox2.Focus() 'Enter key moves to next control

    End Sub

     

     

     

    If you need a negative number, add a statement to accept a minus sign at the beginning of the number.

     

    Code Snippet

    Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress

    If Not Char.IsDigit(e.KeyChar) Then e.Handled = True

    If e.KeyChar = Chr(8) Then e.Handled = False 'allow Backspace

    If e.KeyChar = "-" And TextBox1.SelectionStart = 0 Then e.Handled = False 'allow negative number

    If e.KeyChar = Chr(13) Then TextBox2.Focus() 'Enter key moves to next control

    End Sub

     

     

     

    If input is from another source, then enter this code in the Validated event, to clear the textbox:

     

    Code Snippet

    Private Sub TextBox6_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles TextBox6.Validating

    If Not IsNumeric(TextBox6.Text) Then TextBox6.Clear()

    End Sub

     

     

    To process the data mathematically, use the TryParse() method to convert the string into a number:

     

     
    Code Snippet

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    Dim number As Integer

    Integer.TryParse(TextBox1.Text, number)

    'do the math with the number variable

    End Sub

     

     

    You can combine the above two events and use the Boolean value of the TryParse method to do both at once.  You may also want to put the focus back on the textbox and issue a MessageBox warning.

     

    Code Snippet

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    Dim number As Integer

    If Integer.TryParse(TextBox1.Text, number) = False Then

       TextBox1.Clear()

    Else

       'do the math with the number variable

    End If

    End Sub

     

     

    When the math processing is complete, display the result either in a textbox or label after converting it to a string:

     

    TextBox2.Text = result.ToString()

     

     

    Saturday, September 22, 2007 5:18 PM

All replies

  • Try: intVar = CInt(txtb.text)

    Hope that works for you Smile

    Tuesday, September 18, 2007 9:05 PM
  • can you do that for anything like that??

     

    It'd be extremely helpful if that was a usual function of VB.

     

    thanks, I think that should fix the problem, but I want to test it first.

    Tuesday, September 18, 2007 9:18 PM
  • Another method:

     

    Intvar as integer = Integer.Parse("1234")

     

    You may also want to add error handling unless you've restricted the textbox entry to just numbers.

     

    Tuesday, September 18, 2007 9:26 PM
  • is that possible?

     

    I'd like to do that, but I've never known how.

     

    if you could tell me that'd be great!

    Tuesday, September 18, 2007 9:29 PM
  • Hi Darth,

     

    Based on your post, you need to restrict the textbox entry to just numbers. Here are many methods. Using the regular expression is one easy method to achieve this. For more information about learning the regular expression, please visit:

    this article ”The 30 Minute Regex Tutorial” By Jim Hollenhorst in the codeproject. When you convert the digit string to integer type, you need to add the error handling. For more information about error handling and throwing exception, please visit: http://msdn2.microsoft.com/en-us/library/5b2yeyab.aspx. Here is the code snippet about how to restrict the textbox entry just numbers.

    Code Snippet

    Dim rxImageCode As Regex = New Regex("(\d+)")

    Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged

    Dim rxMatch As Match = rxImageCode.Match(Me.TextBox1.Text)

    If (rxMatch.Success) Then

    TextBox1.Text = rxMatch.Groups(0).Value

    End If

    End Sub

     

     

     

    Best regards.
    Thursday, September 20, 2007 10:39 AM
    Moderator
  •  

    This appears to be almost right, but the Regex and Match types are not declared, or so says VB 2005 free edition.

     

    Does the fact that I'm using VB 2005 Free Edition have anything to do with that, or is there another way to do it?

     

    These are the only problems with the aforementioned code snippets.  I just need to fix those...does anyone know how?

    Friday, September 21, 2007 6:36 PM
  • Hi darth_mascurse,

     

    Put one button and one textbox on a FORM to try this program please.>>>>

     

    You can use the IsNumeric method to see if the string from the textbox is a number or not or you can use the

     

    TryParse and Parse methods.>>

     

    Dim myInteger As Integer

    If Integer.TryParse(TextBox1.Text, myInteger) = True Then myInteger = Integer.Parse(TextBox1.Text)

    MessageBox.Show("The myInteger value is now= " & myInteger.ToString)

     

    Important Note: This program also proves that if you type say 7 point 2 ( 7.2 ) then the Integer part ( the number 7 ) is not returned with the Integer.Parse command.

     

     

    Code Snippet

     

    Public Class Form1

     

    'The next highlighted line should be one line of code in your code window.>>>>

     

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

     

    'You can do one of two things,.

    'Check to see if it a number using IsNumeric.>>

    'myNumber As Object as you don't know

    'if it will be an INTEGER or Double or other TYPE of number.

    Dim myNumber As Object = ""

    If IsNumeric(TextBox1.Text) = True Then myNumber = CObj(TextBox1.Text)

    MessageBox.Show("OBJECT 'myNumber' is " & myNumber.ToString)

     

     

    'or use TryParse and Parse.>>

    Dim number As Decimal = 0

    If Decimal.TryParse(TextBox1.Text, number) = True Then number = Decimal.Parse(TextBox1.Text)

    If IsNumeric(TextBox1.Text) Then

    MessageBox.Show("If you type a number you get>> " & number.ToString)

    Else

    MessageBox.Show("ELSE the 'number' value is now = " & number.ToString)

    End If

     

     

    Dim myInteger As Integer

    If Integer.TryParse(TextBox1.Text, myInteger) = True Then myInteger = Integer.Parse(TextBox1.Text)

    MessageBox.Show("The myInteger value is now = " & myInteger.ToString)

     

    End Sub

    End Class

     

     

     

     

     

    Regards,

     

    John

     

    Saturday, September 22, 2007 1:48 PM
  • First of all, ALL input into the computer is done with strings, including textboxes. In order to process the string data mathematically, it must be converted into a number type.  Then, to display the results, the numeric data must be converted back into a string.

     

    To restrict input to integers in a textbox while user enters data from the keyboard, use the following code.

     

    If you want only a positive integer, place this code in the textbox's Keypress event. It will not accept any key other than the digits from 0 to 9, but it will accept the backspace key. The Enter key may be used to move to the next control.

     

    Code Snippet

    Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress

    If Not Char.IsDigit(e.KeyChar) Then e.Handled = True

    If e.KeyChar = Chr(8) Then e.Handled = False 'allow Backspace

    If e.KeyChar = Chr(13) Then TextBox2.Focus() 'Enter key moves to next control

    End Sub

     

     

     

    If you need a negative number, add a statement to accept a minus sign at the beginning of the number.

     

    Code Snippet

    Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress

    If Not Char.IsDigit(e.KeyChar) Then e.Handled = True

    If e.KeyChar = Chr(8) Then e.Handled = False 'allow Backspace

    If e.KeyChar = "-" And TextBox1.SelectionStart = 0 Then e.Handled = False 'allow negative number

    If e.KeyChar = Chr(13) Then TextBox2.Focus() 'Enter key moves to next control

    End Sub

     

     

     

    If input is from another source, then enter this code in the Validated event, to clear the textbox:

     

    Code Snippet

    Private Sub TextBox6_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles TextBox6.Validating

    If Not IsNumeric(TextBox6.Text) Then TextBox6.Clear()

    End Sub

     

     

    To process the data mathematically, use the TryParse() method to convert the string into a number:

     

     
    Code Snippet

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    Dim number As Integer

    Integer.TryParse(TextBox1.Text, number)

    'do the math with the number variable

    End Sub

     

     

    You can combine the above two events and use the Boolean value of the TryParse method to do both at once.  You may also want to put the focus back on the textbox and issue a MessageBox warning.

     

    Code Snippet

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    Dim number As Integer

    If Integer.TryParse(TextBox1.Text, number) = False Then

       TextBox1.Clear()

    Else

       'do the math with the number variable

    End If

    End Sub

     

     

    When the math processing is complete, display the result either in a textbox or label after converting it to a string:

     

    TextBox2.Text = result.ToString()

     

     

    Saturday, September 22, 2007 5:18 PM
  • THANK YOU!!!!!!

     

    That was exactly what I needed, Solitaire!

     

    The program is now working perfectly and I have EXACTLY what I want.

     

    THANKS TO ALL THAT HELPED!!!

    Saturday, September 22, 2007 6:32 PM
  • Hi Solitaire,

     

    Very good answer, and to-the point.

     

     

     

    Regards,

     

    John.

     

    Saturday, September 22, 2007 7:10 PM
  • Hi there, 

    How do I write a code to display an integer value in a text box?

    ---Example----

    int = answer:

    2+3= answer;

    Print answer in text box Text1.

    ---Example---

    In other words, after doing a sum I want to write the integer answer inside a text box.
    Saturday, September 13, 2008 8:38 PM
  • natwel said:

    Hi there, 


    How do I write a code to display an integer value in a text box?

    ---Example----

    int = answer:

    2+3= answer;

    Print answer in text box Text1.

    ---Example---

    In other words, after doing a sum I want to write the integer answer inside a text box.



    Hi natwel,

    Are you trying to use Visual Basic.Net ( VB.Net )?

    Your code using semi-colons looks like C# or C++ if so try the appropriate forums please.>>

    http://social.msdn.microsoft.com/Forums/en-US/category/visualcsharp


    http://social.msdn.microsoft.com/Forums/en-US/category/visualc





    Regards,

    John

    For links to VB.Net tutorials see here.>> http://social.msdn.microsoft.com/Forums/en-US/vblanguage/thread/29f2179b-997b-4115-a96d-a0834853b835
    Sunday, September 14, 2008 12:10 AM