This program is supposed to accept in valid candidates for voting, add the names typed in a text box to a list box. In the list box the user may double click on the candidate they choose. After the tally button is clicked a list box displaying the candidates' Names and votes will appear along side the other list box.
My problem is that the lstTallies only displays the last voted candidate.
Below is my code
Public Class Form1
Dim maxVotes As Integer
Dim winner As String
Dim votes() As Integer
Dim index As Integer
Dim candidates As String
Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
If Not isValidInput(txtNewCandidate.Text) Then
Exit Sub
End If
lstCandidates.Items.Add(txtNewCandidate.Text)
txtNewCandidate.Clear()
txtNewCandidate.Focus()
ReDim Preserve votes(index)
index += 1
End Sub
Private Function isValidInput(ByRef firstName As String) As Boolean
If IsNumeric(txtNewCandidate.Text) Or txtNewCandidate.Text = "" Then
MsgBox("Please input a valid candidate name.")
txtNewCandidate.Focus()
Return False
Else
Return True
End If
End Function
Private Sub btnTally_Click(sender As Object, e As EventArgs) Handles btnTally.Click
lstTallies.Visible = True
lblTally.Visible = True
lstTallies.Items.Add(lstCandidates.Text & " " & votes(lstCandidates.SelectedIndex))
End Sub
Private Sub lstCandidates_DoubleClick(sender As Object, e As EventArgs) Handles lstCandidates.DoubleClick
If lstCandidates.SelectedIndex = -1 Then
MsgBox("Select a candidate by double-clicking")
End If
votes(lstCandidates.SelectedIndex) += 1
MsgBox("Vote Tallied")
End Sub
End Class
Try this:
Assuming the index of the Candidate and his/her Vote are the same:
Private Sub btnTally_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnTally.Click
lstTallies.Visible = True
lblTally.Visible = True
For i = 0 To lstCandidates.Items.Count - 1
lstTallies.Items.Add(lstCandidates.Items(i).ToString & " - " & votes(i))
Next
End Sub
You cannot get the contents of the ListBox unless you iterate it.
Related
Please consider adding a description to this question to attract more helpful responses.
Public Class Form1
Private Sub BtnCalculateRevenue_Click(sender As Object, e As EventArgs) Handles BtnCalculateRevenue.Click
Dim intvalue As Integer = CInt(TxtInputClassA.Text)
Dim intvalue2 As Integer = CInt(TxtInputClassB.Text)
Dim intvalue3 As Integer = CInt(TxtinputClassC.Text)
Dim total As Double
Try
LblStatus.Text = String.Empty
LblClassAResult.Text = (intvalue * 15).ToString("c")
LblClassBResult.Text = (intvalue2 * 12).ToString("c")
LblClassCResult.Text = (intvalue3 * 9).ToString("c")
total = CDbl((intvalue * 15) + (intvalue2 * 12) + (intvalue3 * 9))
LblTotal.Text = total.ToString("c")
Catch
LblStatus.Text = "Please Enter a Number"
End Try
End Sub
Private Sub BtnExit_Click(sender As Object, e As EventArgs) Handles BtnExit.Click
Me.Close()
End Sub
Private Sub BtnClear_Click(sender As Object, e As EventArgs) Handles BtnClear.Click
TxtInputClassA.Clear()
TxtInputClassB.Clear()
TxtinputClassC.Clear()
LblClassAResult.Text = String.Empty
LblClassBResult.Text = String.Empty
LblClassCResult.Text = String.Empty
LblTotal.Text = String.Empty
End Sub
End Class
VB Entering a Non_Numeric value crashes the program
Validation is built right into Windows Forms so you should make use of it. If you want to force the user to enter numbers in each of three TextBoxes then you can do this:
Private Sub TextBoxes_Validating(sender As Object, e As ComponentModel.CancelEventArgs) Handles TextBox3.Validating, TextBox2.Validating, TextBox1.Validating
Dim tb = DirectCast(sender, TextBox)
If Not Integer.TryParse(tb.Text, Nothing) Then
'Select all the invalid text and highlight it.
tb.SelectAll()
tb.HideSelection = False
MessageBox.Show("Please enter a whole number",
"Invalid Input",
MessageBoxButtons.OK,
MessageBoxIcon.Exclamation)
'Remove highlight when TextBox is not focused.
tb.HideSelection = True
'Don't let the control lose focus while data is invalid.
e.Cancel = True
End If
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If ValidateChildren() Then
'All data is valid so proceed.
Dim n1 = CInt(TextBox1.Text)
Dim n2 = CInt(TextBox2.Text)
Dim n3 = CInt(TextBox3.Text)
'...
End If
End Sub
The ValidateChildren method will raise the Validating event for every control on the form and return False if any fail validation, i.e. e.Cancel is set to True in any event handlers, so that ensures that even controls that never received focus will be validated before the data is used.
Its bombing out on your cast "CInt(*value*)" so you can fix the code a couple ways. You can move your try above the casts like...
Try
Dim intvalue As Integer = CInt(TxtInputClassA.Text)
Dim intvalue2 As Integer = CInt(TxtInputClassB.Text)
Dim intvalue3 As Integer = CInt(TxtinputClassC.Text)
Dim total As Double
LblStatus.Text = String.Empty
You can do a data validation on your inputs and exit if they aren't all numeric (put this above your Dim intvalue code)
For Each value As String In {TxtInputClassA.Text, TxtInputClassA.Text, TxtInputClassA.Text}
If Not IsNumeric(TxtInputClassA.Text) Then
LblStatus.Text = "Please Enter a Number"
Exit Sub
End If
Next
Instead of casting as an int, use the tryparse method on Int32...
Dim intvalue As Integer
If Not Int32.TryParse(TxtInputClassA.Text, intvalue) Then
Exit Sub
End If
Or you could intercept the keypresses on each text box so that only numbers can be entered
Private Sub TxtInputClassA_KeyPress(sender As Object, e As KeyPressEventArgs) Handles TxtInputClassA.KeyPress
If Not Char.IsDigit(e.KeyChar) Then
e.Handled = True
End If
End Sub
You can make that routine universal and append the event handler for all three text boxes like...
Private Sub EnforceOnlyNumericKeyPresses(sender As Object, e As KeyPressEventArgs) Handles TxtInputClassA.KeyPress, TxtInputClassB.KeyPress, TxtInputClassC.KeyPress
If Not Char.IsDigit(e.KeyChar) Then
e.Handled = True
End If
End Sub
Choose your favorite or do all of them, lots of choices.
Replace your textboxes with NumericUpDown controls and retrieve their .Value for your calculation. NUDs don't allow non numeric input and can have a fixed number of decimal places which may also be useful in a financial context
sorry I'm a newbie and I'm trying to write a program to get ten integers from user with a an Inputbox or Textbox and displays the biggest and lowest one in a label with visual basic. I'll be appreciated if you help me out with this.
Thank you. this is my solution. I don't know how to compare these ten numbers with each other.
Private Sub btnShow_Click(sender As Object, e As EventArgs) Handles btnShow.Click
Dim i, Container, Max, Numbers
Max = 0
i = 1
While (i <= 10)
Numbers = InputBox("please enter a number", "Enter a number")
Max = Numbers
Container = Container & " " & Numbers
i = i + 1
End While
lblresult.Text = Container
End Sub
conceptually speaking you should use a List(Of Integer) or List(Of Double), perform the loop 10 times adding the value into the list.
Suppose this is our list
Dim container As New List(Of Integer)
To get input
Dim userInput = ""
Dim input As Integer
userInput = InputBox("please enter a number", "Enter a number")
If Integer.TryParse(userInput, input) Then
container.Add(input)
End If
After the loop
Console.WriteLine($"Min: {container.Min()} Max: {container.Max()}")
Does this make sense to you ?
Edit, based on asking for Windows Forms example.
You could do the following instead of a InputBox, requires a label, a button and a TextBox.
Public Class MainForm
Private container As New List(Of Integer)
Private Sub CurrentInputTextBox_KeyPress(sender As Object, e As KeyPressEventArgs) _
Handles CurrentInputTextBox.KeyPress
If Asc(e.KeyChar) <> 8 Then
If Asc(e.KeyChar) < 48 Or Asc(e.KeyChar) > 57 Then
e.Handled = True
End If
End If
End Sub
Private Sub Form1_Shown(sender As Object, e As EventArgs) Handles Me.Shown
CurrentLabel.Text = "Enter number 1"
End Sub
Private Sub ContinueButton_Click(sender As Object, e As EventArgs) _
Handles ContinueButton.Click
If Not String.IsNullOrWhiteSpace(CurrentInputTextBox.Text) Then
container.Add(CInt(CurrentInputTextBox.Text))
CurrentLabel.Text = $"Enter number {container.Count + 1}"
If container.Count = 10 Then
ContinueButton.Enabled = False
CurrentLabel.Text =
$"Count: {container.Count} " &
$"Max: {container.Max()} " &
$"Min: {container.Min()}"
Else
ActiveControl = CurrentInputTextBox
CurrentInputTextBox.Text = ""
End If
End If
End Sub
End Class
I really didn't want to do your homework for you but I was afraid you might be hopelesly confused.
First let's go over your code. See comments
Private Sub btnShow_Click(sender As Object, e As EventArgs) Handles btnShow.Click
Dim i, Container, Max, Numbers 'Don't declare variables without an As clause
Max = 0 'Max is an object
i = 1 'i is and object
While i <= 10 'the parenthesis are unnecessary. You can't use <= 2 with an object
Numbers = InputBox("please enter a number", "Enter a number")
Max = Numbers
Container = Container & " " & Numbers 'Container is an object; you can't use & with an object
i = i + 1 'Again with the object i can't use +
End While
lblresult.Text = Container
End Sub
Now my approach.
I created a List(Of T) at the Form level so it can be seen from different procedures. The T stands for type. I could be a built in type or type you create by creating a Class.
The first click event fills the list with the inputted numbers. I used .TryParse to test if the input is a correct value. The first parameter is a string; the input from the user. The second parameter is a variable to hold the converted string. .TryParse is very clever. It returns True or False base on whether the input string can be converted to the correct type and it fills the second parameter with the converted value.
The second click event loops through the list building a string to display in Label1. Then we use methods available to List(Of T) to get the numbers you desire.
Private NumbersList As New List(Of Integer)
Private Sub FillNumberList_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim i As Integer
While i < 10
Dim input = InputBox("Please enter a whole number")
Dim inputInt As Integer
If Integer.TryParse(input, inputInt) Then
NumbersList.Add(inputInt)
i += 1 'We only increment i if the parse is succesful
End If
End While
MessageBox.Show("Finished Input")
End Sub
Private Sub DisplayResults_Click(sender As Object, e As EventArgs) Handles Button2.Click
Label1.Text = "You input these numbers "
For Each num In NumbersList
Label1.Text &= $"{num}, "
Next
Label2.Text = $"The largest number is {NumbersList.Max}"
Label3.Text = $"The smallest number is {NumbersList.Min}"
End Sub
enter image description here <<< my interface
I am working on something for my exam next week.
I must use Visual Basic. I am supposed to create an array with an integer and string. Integer = distance String = name. there will be 2 textboxes, 2 labels and 2 buttons.
txtname.text, txtdistance.text, lblname, lbldistance, btninputdata and btnshowcontent
btninputdata should be disabled after filling the 30 arrays and making btnshowcontent to be visible and show all the 30 values (inserted values via textboxes) in lblname and lbldistance.
Whereas they both need to be inserted via a textbox store into the array and then using a btnshowcontent the stored array should be displayed on separate labels of name and distance.
My codes:
Public Class Form1
Dim ara(29) As String
Private Sub Form1_Load(sender As Object, e As EventArgs)
End Sub
Private Sub btninputdata_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btninputdata.Click
If txtname.Text <> "" Then
For h As Integer = 0 To 29
If ara(h) = "" Then
ara(h) = txtname.Text
txtname.Clear()
Exit Sub
End If
Label1.Text = ara.ToString()
Next
MsgBox("arry full")
btninputdata.Visible = False
btnshowcontent.Visible = True
End If
End Sub
Private Sub btnshowcontent_Click(sender As Object, e As EventArgs) Handles btnshowcontent.Click
'ListBox1.Items.Clear()
'ListBox1.Items.AddRange(ara)
''Label1.Text &= ara(I) & ""
End Sub
Private Sub Form1_Load_1(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
End Class
You'll want to start with something like this. Not sure how you're really trying to display everything, though. You'd probably want to do validation on the distance field also.
Public Class Form1
Dim Ara As New List(Of MyGroup)
Private Sub btninputdata_Click(sender As Object, e As EventArgs) Handles btninputdata.Click
If txtName.Text.Trim() <> String.Empty Then
Ara.Add(New MyGroup With {.Name = txtName.Text, .Distance = txtDistance.Text})
If Ara.Count >= 30 Then
'Show/Hide buttons
End If
End If
End Sub
End Class
Public Class MyGroup
Public Name As String
Public Distance As Decimal
End Class
If you truly must use an array you can do something like this:
Public Class Form1
Private Ara(29) As MyGroup
Private Sub btninputdata_Click(sender As Object, e As EventArgs) Handles btninputdata.Click
If txtName.Text.Trim() <> String.Empty Then
Dim EmptyLocation = Array.FindIndex(Ara, Function(x) x Is Nothing)
If EmptyLocation > -1 Then
Ara(EmptyLocation) = New MyGroup With {.Name = txtName.Text, .Distance = txtDistance.Text}
Return
End If
'Show/Hide buttons
'Display the results however.
End If
End Sub
End Class
Public Class MyGroup
Public Name As String
Public Distance As Decimal
End Class
I want to be able to select an index on my ListBox.My ListBox is getting getting values depending on the selected index, however when I try to select an index in the listbox, it gets the values but stays unselected. I have to select the index a second time for it to be selected. Why is that?
here is my code on the selectedIndexChanged:
Private Sub listResults_SelectedIndexChanged(sender As Object, e As EventArgs) Handles listResults.SelectedIndexChanged
UpdateContactInformationFromRegistry()
End Sub
The UpdateContactInformationFromRegistry() method:
Private Sub UpdateContactInformationFromRegistry()
Dim contact As Contact = m_contacts.GetContact(listResults.SelectedIndex)
cmbCountries.SelectedIndex = DirectCast(contact.AddressData.Country, Integer)
txtFirstName.Text = contact.FirstName
txtLastName.Text = contact.LastName
txtStreet.Text = contact.AddressData.Street
txtZip.Text = contact.AddressData.ZipCode
txtCity.Text = contact.AddressData.City
End Sub
UPDATE V2
cmbCountries.SelectedIndexChanged event handler
Private Sub cmbCountries_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbCountries.SelectedIndexChanged
UpdateGUI()
End Sub
UpdateGUI() method
Private Sub UpdateGUI()
Dim strContacts() As String = m_contacts.GetContactInfo()
If (strContacts IsNot Nothing) Then
listResults.Items.Clear()
listResults.Items.AddRange(strContacts)
lstCount.Text = listResults.Items.Count.ToString()
End If
End Sub
I have an order form I created in VB.NET and I have a ListBox that is populated by order. You can double click on the order and it populates the order number in the order form. The problem I'm having is that it populates the TextBox with both the order number and the persons name. How can I use a delimiter to only pull out the order number and not the name also.
Imports Business_Objects
Public Class frmSummary
Private ctrl As Controller
Dim listID As ArrayList
Private Sub frmSummary_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
ctrl = CType(MdiParent, frmMain).ctrl
Dim list As ArrayList
list = ctrl.GetOrders
Dim order As Business_Objects.Order
For Each order In list
lstOrders.Items.Add(order.ID & "," & " " & order.Server)
Next
End Sub
Private Sub lstOrders_DoubleClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles lstOrders.DoubleClick
Dim result As Boolean = False
If lstOrders.Text <> "" Then
result = True
Dim frm As New OrderForm
frm.MdiParent = Me.MdiParent
frm.Show()
frm.txtOrderNo.Text = lstOrders.Text
frm.btnFetch.PerformClick()
Else
MessageBox.Show("there are no orders here to click")
End If
End Sub
Private Sub btnRefresh_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRefresh.Click
lstOrders.Items.Clear()
ctrl = CType(MdiParent, frmMain).ctrl
Dim list As ArrayList
list = ctrl.GetOrders
Dim order As Business_Objects.Order
For Each order In list
lstOrders.Items.Add(order.ID & " " & order.Server)
Next
End Sub
End Class
If all of your data is being stored as a single field, or something like:
4322305 John Smith Carrots $3.00
845825 Sam White Oranges $1.25
Then you can read each record as a string, and then use split that into an array based on " " as your delimiter.
The code would look something like:
dim myArray as string() = myLongTextRecord.Split(" ")
And in that format,
textBoxName.Text = myArray[1]
You're almost there. You could use the split function, but another approach would be to add the Order object directly to the listbox and not text.
Private Sub frmSummary_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
ctrl = CType(MdiParent, frmMain).ctrl
Dim list As ArrayList
list = ctrl.GetOrders
Dim order As Business_Objects.Order
For Each order In list
lstOrders.Items.Add(order)
Next
End Sub
Private Sub lstOrders_DoubleClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles lstOrders.DoubleClick
Dim result As Boolean = False
If lstOrders.Text <> "" Then
result = True
Dim frm As New OrderForm
frm.MdiParent = Me.MdiParent
frm.Show()
frm.txtOrderNo.Text = DirectCast(lstOrders.SelectedItem, Order).ID.ToString
frm.btnFetch.PerformClick()
Else
MessageBox.Show("there are no orders here to click")
End If
End Sub
You'll need to go into the Order object and override the .ToString function so that the text in the Listbox displays whatever value you want (ie. Return ID & "," & " " & Server)