Problem using CInt() with textbox

Problem using CInt() with textbox

• spotl

  I just noticed, you places that on the textchanged event so everytime a textchanged occurs, it wont work. You are best to do this on a button click. Also be sure that all the textboxes do have text in them (of integers).
  
  

• kid_kaneda

  The following should work for you using the textchanged event but validating the textbox fields to ensure that we have three numeric fields - I'd changed the type to double to make it a little more flexible allowing any text to be entered but you could always restrict the textboxes to allow numbers of control character keypress only.

  Public Class Form1
  Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged
  Try
  Me.Label1.Text = VerifyNumber(Me.TextBox1.Text) + VerifyNumber(Me.TextBox2.Text) + VerifyNumber(Me.TextBox3.Text)
  Catch ex As Exception
  Me.Label1.Text = ""
  MsgBox(ex.Message)
  End Try
  End Sub

  Function VerifyNumber(ByVal x As String) As Double
  If x.Length = 0 Then
  Return 0
  Else
  If IsNumeric(x) Then
  Return CType(x, Double)
  Else
  Throw New Exception("Is not numeric or blank")
  End If
  End If
  End Function
  End Class

  
  

• Kevin Rodgers

  As stated, you have to test the value of the Text property and ensure that it can be converted to a decimal value. But it should be noted that the TextChanged event will be raised while the form is initially loading so you have to be ready to handle an empty string.

  The code for validating the input and doing the calculation can be placed on the TextChanged event, and when trimmed down, looks something like:

  Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged

  Dim val As Decimal

  Dim total As Decimal = 0

  If Decimal.TryParse(TextBox1.Text, val) Then

  total += val

  End If

  If Decimal.TryParse(TextBox2.Text, val) Then

  total += val

  End If

  If Decimal.TryParse(TextBox3.Text, val) Then

  total += val

  End If

  Me.Label1.Text = total.ToString

  End Sub

  Personally, I would add some indicator that appears when the text entered cannot be converted into a decimal - something like changing the color of the TextBox. The modified code might look like:

  Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged

  Dim val As Decimal

  Dim total As Decimal = 0

  If Decimal.TryParse(TextBox1.Text, val) Then

  total += val

  TextBox1.BackColor = SystemColors.Window

  TextBox1.ForeColor = SystemColors.WindowText

  Else

  TextBox1.BackColor = Color.Crimson

  TextBox1.ForeColor = Color.White

  End If

  If Decimal.TryParse(TextBox2.Text, val) Then

  total += val

  TextBox2.BackColor = SystemColors.Window

  TextBox2.ForeColor = SystemColors.WindowText

  Else

  TextBox2.BackColor = Color.Crimson

  TextBox2.ForeColor = Color.White

  End If

  If Decimal.TryParse(TextBox3.Text, val) Then

  total += val

  TextBox3.BackColor = SystemColors.Window

  TextBox3.ForeColor = SystemColors.WindowText

  Else

  TextBox3.BackColor = Color.Crimson

  TextBox3.ForeColor = Color.White

  End If

  Me.Label1.Text = total.ToString

  End Sub

  Hope that helps!

  
  
  

• varunsagii

  you need to convert the values to an integer then do your calc and finally display it. You need to however be sure that the text is numeric otherwise it will fail so be sure to do some validation.

  this should work from your code snippet:

  Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged

  Dim tx1 As Integer = Convert.ToInt32(Me.TextBox1.Text)

  Dim tx2 As Integer = Convert.ToInt32(Me.TextBox2.Text)

  Dim tx3 As Integer = Convert.ToInt32(Me.TextBox3.Text)

  Dim totalCalc as Integer = tx1 + tx2 + tx3

  Me.Label1.Text = totalCalc.ToString()

  End Sub

  does this work

  
  
  

• No-spam Sam

  To insure a numeric value and allow for decimals adjust the given code as follows

  Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged

  Dim tx1 As decimal

  Dim tx2 As decimal

  Dim tx3 As decimal

  If isNumeric(Me.TextBox1.Text) then

  tx1= Convert.Todecimal (Me.TextBox1.Text)

  else

  tx1=0

  end if

  if isNumeric((Me.TextBox2.Text)then

  tx2= Convert.Todecimal (Me.TextBox2.Text)

  else tx2 = 0

  end if

  if IsNumeric((Me.TextBox3.Text) then

  tx3= Convert.Todecimal (Me.TextBox3.Text)

  else

  tx3 = 0

  end if

  Dim totalCalc as Integer = tx1 + tx2 + tx3

  Me.Label1.Text = totalCalc.ToString()

  End Sub

  
  
  

• Vl.K

  No... I have the text property of both textboxes set to 0, initially.

  But running the code, results the error: Input sequence was not in an incorrect format.

  What is this Not in an incorrect format

  Thanks,

  Lucas

  
  
• Problem using CInt() with textbox