Displaying winner's name in picture box - vb.net

Question

Below is code for a simple voting system I am coding.
Public Class Form1
Dim winner As String
Dim maxVotes As Integer
Dim votes() As String
Dim index As String
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
For i = 0 To lstCandidates.Items.Count - 1
lstTallies.Items.Add(lstCandidates.Items(i).ToString & " - " & votes(i))
Next
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
Private Sub pbxWinner_Click(sender As Object, e As EventArgs) Handles pbxWinner.Click
End Sub
End Class
The voter must double click on their choice of candidate in the first list box. The user then tallies the votes by clicking on a button and a second list box will appear with the votes per candidate.
Now I need to display the winner (or winners, if there is a tie) in a picture box, pbxWinner. I am not sure how to accomplish this. Any clues?
Here is what i am trying to do, though the code below doesn't work.
Private Function candidateWinner(ByRef winner As String) As Boolean
For i As Integer = 0 To lstCandidates.SelectedIndex - 1
If votes(i) > maxVotes Then
maxVotes += 1
End If
Next
g = pbxWinner.CreateGraphics
g.TranslateTransform(10.0F, 0.0F)
g.DrawString(winner, New Font("Arial", 7, FontStyle.Regular), Brushes.DarkBlue, New PointF(0, 0))
Return True
End Function

Answer 1

Your code is actually working fine for an initial paint, but when the picture box image doesn't have its own bitmap set, a number of events can repaint its graphics behind the scenes(even as simple as minimizing/mazimizing the form, and a whole bunch of other ones), so in effect your text seems to never appear at all or disappear almost instantly when in reality it's probable getting repainted. To fix this, use a bitmap for the graphics object's reference, paint the bitmap's graphics, and then assign the bitmap to the picturebox's image property. This will make the image persistent...give this code a try in your candidateWinner function after the for loop:
Dim bmp As New Bitmap(pbxWinner.Width, pbxWinner.Height)
Dim g As Graphics = Graphics.FromImage(bmp)
g.TranslateTransform(10.0F, 0.0F)
g.DrawString(winner, New Font("arial", 7, FontStyle.Regular), Brushes.DarkBlue, 0, 0)
pbxWinner.Image = bmp
...If you still aren't seeing text, make sure the winner string has the correct value set, I tested this code and it showed my test string correctly
Edit for Comment:
That's because of the logic you're using to calculate the winner...you are just checking to see if the currently selected candidate's vote count is higher than maxVotes and then incrementing the max by 1. If you wanted to stick with that sort of logic for picking the winner, you would want to iterate through ALL of the candidates(not just those from index 0 to the currently selected one), and if their vote count is higher than the max, then set the max EQUAL to their vote count. Then the next candidate in the loop will have their count checked against the previous max. However, tracking the winner could be done a lot easier if you just use a dictionary since you are allowing candidates to be added, and you must change your "winner" logic to actually check who has the most votes out of everyone entered. A bare bones example of that would look like this:
Dim dctTally As Dictionary(Of String, Integer)
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
dctTally = New Dictionary(Of String, Integer)
End Sub
Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
dctTally.Add(txtNewCandidate.Text, 0)
lstCandidates.Items.Add(txtNewCandidate.Text)
End Sub
Private Sub lstCandidates_DoubleClick(sender As Object, e As EventArgs) Handles lstCandidates.DoubleClick
dctTally(lstCandidates.text) += 1
End Sub
Private Sub pbxWinner_Click(sender As Object, e As EventArgs) Handles pbxWinner.Click
Dim winner = dctTally.Aggregate(Function(l, r) If(l.Value > r.Value, l, r)).Key
Dim bmp As New Bitmap(pbxWinner.Width, pbxWinner.Height)
Dim g As Graphics = Graphics.FromImage(bmp)
g.TranslateTransform(10.0F, 0.0F)
g.DrawString(winner, New Font("arial", 7, FontStyle.Regular), Brushes.DarkBlue, 0, 0)
pbxWinner.Image = bmp
End Sub
This way, the program allows as many names as you want to be added to the candidates list, and will add a vote count to their name each time their name is double-clicked on. Then, when your winner pixturebox is clicked, it will find the dictionary with the highest vote count and display their name in the winner-box.

Answer 2

You can try this to draw the winners:
Private Sub candidateWinner()
Dim y As Single = 0
maxVotes = votes.Select(Function(x) Convert.ToInt32(x)).Max()
For i = 0 To UBound(votes)
If votes(i) = maxVotes.ToString() Then
g = pbxWinner.CreateGraphics
g.TranslateTransform(10.0F, 0.0F)
g.DrawString(lstCandidates.Items(i).ToString(), New Font("Arial", 7, FontStyle.Regular), Brushes.DarkBlue, New PointF(0, y))
y += 10
g.Dispose()
End If
Next
End Sub