I am having some issues with my VB.net database, I am trying to present a chart which shows a composition of customers who are members or not from a graph. The graph works, however; there are duplicates (as there are 8 bars instead of 2 bars):
For my database, I've used lists rather than conventional methods such as SQL. However, I'm uncertain if I've made a mistake or I'm missing something, here's the code:
Dim a As Integer
Dim b As Integer
Dim status As String
Dim countList As New List(Of Integer)
Dim statusList As New List(Of String)
Dim yesList As New List(Of String)
Dim count As Integer = 0
For a = 0 To memberList.Count - 1
status = memberList.Item(a).memberStatus
count = 0
For b = 0 To memberList.Count - 1
If status = memberList.Item(b).memberStatus Then
count = count + 1
End If
Next
statusList.Add(memberList.Item(a).memberStatus)
countList.Add(count)
Next
For i = 0 To countList.Count - 1
Debug.Print(memberList(i).memberStatus & countList(i).ToString)
Next
Chart_MemMostPopularTown.ChartAreas("ChartArea1").AxisX.MinorTickMark.Enabled = True
Chart_MemMostPopularTown.ChartAreas("ChartArea1").AxisX.Interval = 1
Chart_MemMostPopularTown.ChartAreas("ChartArea1").AxisX.IsLabelAutoFit = True
Chart_MemMostPopularTown.ChartAreas("ChartArea1").AxisX.LabelAutoFitStyle = DataVisualization.Charting.LabelAutoFitStyles.DecreaseFont
Chart_MemMostPopularTown.Series(0).Points.DataBindXY(statusList, countList)
If there is anything I've missed out, or if I've been too vague; please do let me know. I'm new to this site BTW so apologise for mistakes or lack of clarity.
Kind Regards
Related
I am currently writing a (multiple choice) quiz program using VB.net I have read the answer options in from a .txt file into a single dimension temporary array however I would like to split this down into each question and the answer options for each questions into a 2D array so that (0,0) would be option A for question one and then (0,1) would be Option B for question 1 etc and then (1,0) would be option A for question 2. Below is the method I have tried however I get the error: "Object reference not set to an instance of an object" when adding 1 to a variable when I try and run this section of the code optnum = optnum + 1 Any help would be greatly appreciated, either fixing my code below or suggesting another method.
Dim optnum As Integer
Dim tempq As Integer = 0
Gameload(Phase_3.sounds)
Questionnum = 0
L_start.Hide()
optnum = 0
'splits the temp array down into options for each question
For i = 0 To 39
questions(tempq, optnum) = temparray(i)
optnum = optnum + 1
'there are 4 options for each question
'moves on to the next question when there is 4 options in the question
If optnum = 3 Then
tempq = tempq + 1
optnum = 0
End If
Next
For i = 0 To 3
L_option1.Text = questions(0, i)
Next
question_set()
Edit:
Here is the new full code I am still getting the error: Object reference not set to an instance of an object but now at the next in this section of code.
'''
For optnum = 0 To 3
questions(i, optnum) = temparray(i * 4 + optnum)
Next
'''
Thank you for all the help so far
'''
Public Class Game
Dim submission As Integer
Dim Correct_ans As Integer
Dim temparray() As String
Dim questions(,) As String
Dim Questionnum As Integer
Dim rs As New Resizer
Private Sub Game_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'finds all components on the screen in preperation if the screen resizes
rs.FindAllControls(Me)
L_start.Show()
End Sub
Private Sub Game_Resize(sender As Object, e As EventArgs) Handles Me.Resize
'resizes all components on the screen to same proportions
rs.ResizeAllControls(Me)
End Sub
Sub Gameload(ByVal sounds As String)
Dim pack As String
'reads in the sound pack
pack = My.Resources.ResourceManager.GetString(sounds)
Phase_3.Close()
'splits the pack into an array so that it can be broken down into questions
temparray = pack.Split(","c)
End Sub
Sub L_start_Click(sender As Object, e As EventArgs) Handles L_start.Click
Dim optnum As Integer
Dim tempq As Integer = 0
Gameload(Phase_3.sounds)
Questionnum = 0
L_start.Hide()
optnum = 0
'splits the temp array down into options for each question
For i = 0 To temparray.Count / 4
For optnum = 0 To 3
questions(i, optnum) = temparray(i * 4 + optnum)
Next
Next
For i = 0 To 3
L_option1.Text = questions(0, i)
Next
End Sub
'''
This is just my opinion but I think your aproach would be hard to maintain. I never saw the value of a class until I actually tried one. Maybe this is your chance.
Public Class Quiz
Public Property QuestionNumber As Integer
Public Property Question As String
Public Property AnswerA As String
Public Property AnswerB As String
Public Property AnswerC As String
Public Property AnswerD As String
Public Property CorrectAnswer As String
Public Overrides Function ToString() As String
Return $"Question: {QuestionNumber}.{Question} Answer Choices: {AnswerA}, {AnswerB}, {AnswerC}, {AnswerD} Correct Answer - {CorrectAnswer}"
End Function
End Class
To use your class...
Private QuestionList As New List(Of Quiz)
Private Sub OPCode2()
Dim temparray = File.ReadAllLines("answers.txt")
Dim temparraylocation As Integer
Dim questions = File.ReadAllLines("questions.txt")
Dim correctAnswers = File.ReadAllLines("correct.txt")
For i = 0 To questions.Length - 1
Dim qu As New Quiz
qu.QuestionNumber = i + 1
qu.Question = questions(i)
qu.CorrectAnswer = correctAnswers(i)
qu.AnswerA = temparray(temparraylocation)
temparraylocation += 1
qu.AnswerB = temparray(temparraylocation)
temparraylocation += 1
qu.AnswerC = temparray(temparraylocation)
temparraylocation += 1
qu.AnswerD = temparray(temparraylocation)
temparraylocation += 1
QuestionList.Add(qu)
Next
For Each q In QuestionList
Debug.Print(q.ToString)
Next
End Sub
Where's your declaration for temparray and questions. Will the quiz always have 4 choices and 10 questions?
It might be easier for you to have a nested loop so that i is temparray.count/4 and optnum is 0-3, then you can populate questions(i, optnum) = temparray(i*4+optnum)
Looking at your new code, you haven't initialised the questions variable. Only declared it.
Personally I would change questions to a list(of question), then use Mary's answer.
I have a a table of values, which list item ids by the amount of those items in different qualities, like so:
ID QB QC UI
006780 12 - 6
100780 48 15 8
And so on for a thousand rows. As part of a further wrangling effort, I wish to get the id's and move them elsewhere and position them under each other with 2 blank cells between them. This is the code I've come up with and please bear with me, I'm trying to lear:
Sub laatuJako()
Dim idRange As Range
Dim tyoWb As Workbook
Dim tyoWks As Worksheet
Dim idRivit As Integer
Dim idArray() As Variant
Set tyoWb = ThisWorkbook
Set tyoWks = tyoWb.Sheets("Pivots->Apu")
idRivit = tyoWks.Range("Q7").End(xlDown).Row
ReDim idArray(0)
Dim varCounter As Integer
varCounter = 0
This next loop is a way I could form the array, since it seemed to run into run-time error 9 in the next loop.
For i = 0 To idRivit - 1
tyoWks.Activate
idArray(i) = tyoWks.Range("Q" & 7 + i).Value
varCounter = varCounter + 1
ReDim Preserve idArray(varCounter)
Next i
Dim k As Integer
Dim j As Integer
k = 0
j = 0
Do While k < idRivit
tyoWks.Range("X" & 7 + j).Value = idArray(k)
j = j + 3
k = k + 1
Loop
End Sub
Now the code works, but it seems that (un)helpfully VBA changed the id attribute to a number and printed the ids with numbers in front of them, for example 006780 as 6780. This was not wanted and so I changed the array into a string array, but it made no difference. Now an array is not necessary here and I can just copy-paste them directly using a loop, but I want to understand how I can control something like this, since the issue will come up again in situations where an array would be preferable.
Apologies, if the question is poorly described, there is a first time for everything.
My Goal is to take two rows(FirstName and Surname) Convert them to a single Array of "FirstName, Surname".
This is my terrible code i eventually put together
Private Sub Search_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'DbaPatientDataSet.tblPatientData' table. You can move, or remove it, as needed.
Me.TblPatientDataTableAdapter.Fill(Me.DbaPatientDataSet.tblPatientData)
listFirst.DataSource = Me.TblPatientDataBindingSource
listFirst.DisplayMember = "FirstName"
listLast.DataSource = Me.TblPatientDataBindingSource
listLast.DisplayMember = "Surname"
Dim Lenth As Integer = Me.listFirst.Items.Count - 1
Dim count As Integer = 1
Dim ArrFirst(Lenth) As String
Dim ArrLast(Lenth) As String
For count = 1 To Lenth
ArrFirst(count) = listFirst.Items(count).ToString
ArrLast(count) = listLast.Items(count).ToString
Next count
count = 1
For count = 1 To Lenth
arrFullName(count) = ArrLast(count) & ", " & ArrFirst(count)
Next count
'Arrays Set =====================================================
But with this code i get an Array of
`"Sytem.Data.DataRowView, Sytem.Data.DataRowView"
"Sytem.Data.DataRowView, Sytem.Data.DataRowView"
"Sytem.Data.DataRowView, Sytem.Data.DataRowView"
"Sytem.Data.DataRowView, Sytem.Data.DataRowView"
`
As you can see
Here
There must be an easy way to convert both DataRows to strings then concatenate them together in an array
I am going to search this array using a Binary Search to find a desired name
Thanks
First, I think you are confusing your rows and your columns. You have 2 columns. I went directly to full name but I think you can break it out if you need to.
Dim arrNames(ListBox1.Items.Count - 1) As String
For i As Integer = 0 To ListBox1.Items.Count - 1
arrNames(i) = $"{ListBox1.Items(i)} {ListBox2.Items(i)}"
Next
For Each item In arrNames
Debug.Print(item)
Next
The string with the $ in front is an interpolated string. Sort of an improvement to String.Format.
I know there is an answer but for now you could go direct to the data table to get what you need.
Dim arrNames(ListBox1.Items.Count - 1) As String
Dim i As Integer = 0
Dim dt As DataTable = DbaPatientDataSet.Tables(0)
For Each row As DataRow In dt.Rows
arrNames(i) = $"{row("Surname")}, {row("FirstName")}"
i += 1
Next
For Each item In arrNames
Debug.Print(item)
Next
'assume the names of your columns are Surname and FirstName
If I run your code up, I get the result you are looking for, so I'm not sure what you are missing. In saying that though, you are making things hard on yourself by messing around with arrays :). Just use the dataset rows directly - they are strongly typed and you can check for nulls etc as needed... something like this;
Dim fullNames As New List(Of String) '-- or you could fill your array.
For Each row As DbaPatientDataSet.tblPatientDataRow In ds.tblPatientData
fullNames.Add(row.Surname & ", " & row.FirstName)
Next
Just looking at what you are trying to achieve, if it was me, I would be bringing back the formatted data in my query that fills the dataset i.e. a third, FullName, column.
It has been in the back of my mind. Finally got it for the List Box directly.
Dim arrFullNames(ListBox1.Items.Count - 1) As String
Dim i As Integer = 0
For Each item As DataRowView In ListBox1.Items
arrFullNames(i) = $"{DirectCast(item("Surname"), String)}, {DirectCast(item("Firstname"), String)}"
i += 1
Next
For Each item As String In arrFullNames
Debug.Print(item)
Next
Public Class Form1
Private Sub btnCalculate_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click
Dim Teams() As String = IO.File.ReadAllLines("SBWinners.txt")
Dim Team As String
Dim SteelersWins As Integer = 0
Dim RaidersWins As Integer = 0
Dim PackersWins As Integer = 0
Dim CowboysWins As Integer = 0
Dim GiantsWins As Integer = 0
Dim RamsWins As Integer = 0
Dim RavensWins As Integer = 0
Dim SaintsWins As Integer = 0
Dim FortyNinersWins As Integer = 0
Dim RedskinsWins As Integer = 0
Dim BroncosWins As Integer = 0
Dim PatriotsWins As Integer = 0
Dim ColtsWins As Integer = 0
Dim DolphinsWins As Integer = 0
Dim BearsWins As Integer = 0
Dim JetsWins As Integer = 0
Dim ChiefsWins As Integer = 0
Dim BuccWins As Integer = 0
For Each team In Teams
If team = "Steelers" Then
SteelersWins += 1
End If
If team = "Raiders" Then
RaidersWins += 1
End If
If team = "Packers" Then
PackersWins += 1
End If
If team = "Cowboys" Then
CowboysWins += 1
End If
If Team = "Giants" Then
GiantsWins += 1
End If
If team = "Rams" Then
RamsWins += 1
End If
If team = "Ravens" Then
RavensWins += 1
End If
If team = "Saints" Then
SaintsWins += 1
End If
If team = "Forty-Niners" Then
FortyNinersWins += 1
End If
If team = "Redskins" Then
RedskinsWins += 1
End If
If team = "Broncos" Then
BroncosWins += 1
End If
If team = "Patriots" Then
PatriotsWins += 1
End If
If team = "Colts" Then
ColtsWins += 1
End If
If team = "Dolphins" Then
DolphinsWins += 1
End If
If team = "Bears" Then
BearsWins += 1
End If
If team = "Jets" Then
JetsWins += 1
End If
If Team = "Chiefs" Then
ChiefsWins += 1
End If
If team = "Buccaneers" Then
BuccWins += 1
End If
Next
Dim Wins() As Integer = {SteelersWins, RaidersWins, PackersWins, CowboysWins, GiantsWins, RamsWins, RavensWins, SaintsWins, FortyNinersWins, RedskinsWins,
BroncosWins, PatriotsWins, ColtsWins, DolphinsWins, BearsWins, JetsWins, ChiefsWins, BuccWins}
For Each win In Wins
Array.Sort(Wins)
Array.Reverse(Wins)
lstOutput.Items.Add(win)
Next
End Sub
End Class
What I have right now is code that reads a text file with the names of Superbowl winners, and counts the number of wins by the number of times the team name appears. These wins are then put into an array and sorted in descending order and displayed in a listbox. This all works fine.
My problem is that I need to display the corresponding team name with their number of wins on the same line in the listbox. So, instead of being:
6
5
5
4
4
It needs to be:
6 Steelers
5 49ers
5 Cowboys
4 Giants
4 Packers
And so on.
There are a couple of issues with your code, not the least of which is you are using hard coded names and variables to collect your team information. This is severely limiting if new names are added or names change.
As Plutonix mentioned in the comments you need to use a class to properly identify and collate your information. I also strongly suggest you use a List(of T) collection to contain your data.
The following code does what you desire.
Private Class cls_Team_wins
Public Team_Name As String
Public Wins As Integer
Public Sub New(Name As String)
Team_Name = Name
Wins = 1
End Sub
Public Overrides Function ToString() As String
Return Strings.Right(" " & Wins, 2) & " - " & Team_Name
End Function
End Class
Private Sub btnCalculate_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click
Dim Games = New List(Of cls_Team_wins)
Dim Teams() As String = IO.File.ReadAllLines("SBWinners.txt")
For Each Team As String In Teams
If Team <> "" Then
Dim Team_Win As cls_Team_wins = Games.Find(Function(x) x.Team_Name = Team)
If Team_Win Is Nothing Then
Games.Add(New cls_Team_wins(Team))
Else
Team_Win.Wins += 1
End If
End If
Next
Games.Sort(Function(x, y) -x.Wins.CompareTo(y.Wins))
ListBox1.DataSource = Games
End Sub
The class included the team name and win counter. It over-rides the ToString method so the list box knows what to show as text. The New function requires you pass the team name and presets the win counter to one.
The For Loop checks for and ignores blank team names, this can be an issue reading text files, esp on the last line. Otherwise it will either add a new team to the list if it does not already exist, or it will increment the win counter if it does.
Once the list is built it is reverse sorted (Note the minus sign in the "Function" compare statement, that's a little trick that reverses the sort), and finally given to the listbox as a datasource.
Good luck to you :)
I wish to implement the Dr.D.E.Knuth's Subtractive RANDOM number generation algorithm. I wish to implement an ATM panel on which when very time user log-in the buttons will be scrambled. every button will change its position.
Here is my code:
Public Sub addbutton()
Dim n As Integer = 0
For i As Integer = 0 To 10
' Initialize one variable
btnArray(i) = New System.Windows.Forms.Button
Next i
While (n < 10)
With (btnArray(n))
.Tag = n + 1 ' Tag of button
.Width = 40 ' Width of button
.Height = 40
FlowLayoutPanel1.Controls.Add(btnArray(n))
.Text = Chr(n + 48)
AddHandler .Click, AddressOf Me.ClickButton
n += 1
End With
End While
End Sub
Then, for sending information to button Text, I used:
Dim btn As Button = sender
TextBox1.Text += btn.Text
Now the major task is to shuffle the btnArray() with Random() function.. But I've failed to do this. I managed to get some code for shuffling the array like follows:
Imports System.Security.Cryptography
Public Class ArrayUtilities
Private Random As RNGCryptoServiceProvider = New RNGCryptoServiceProvider
Private Bytes(4) As Byte
Public Function ShuffleArray(ByVal argArr As Array) As Array
Dim FirstArray As New ArrayList(argArr)
Dim SecoundArray As Array = Array.CreateInstance(GetType(Object), FirstArray.Count)
Dim intIndex As Integer
For i As Integer = 0 To FirstArray.Count - 1
intIndex = RandomNumber(FirstArray.Count)
SecoundArray(i) = FirstArray(intIndex)
FirstArray.RemoveAt(intIndex)
Next
FirstArray = Nothing
Return SecoundArray
End Function
Private Function RandomNumber(ByVal argMax As Integer) As Integer
If argMax <= 0 Then Throw New Exception
Random.GetBytes(Bytes)
Dim intValue As Integer = (BitConverter.ToInt32(Bytes, 0)) Mod argMax
If intValue < 0 Then intValue = -intValue
Return intValue
End Function
End Class
Module Module1
Sub Main()
Dim AU As ArrayUtilities
AU = New ArrayUtilities
Dim GivenArray As Integer() = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
Dim NewArray As Array = AU.ShuffleArray(GivenArray)
Dim i As Integer
Dim stb As New System.Text.StringBuilder
stb.Append("GivenArray = {0,1,2,3,4,5,6,7,8,9}")
stb.Append(vbCrLf)
stb.Append("NewArray = {")
For i = 0 To NewArray.Length - 2
stb.Append(NewArray(i).ToString)
stb.Append(", ")
Next
stb.Append(NewArray(NewArray.Length - 1).ToString)
stb.Append("}")
Console.Write(stb.ToString)
Console.Read()
End Sub
End Module
Yet, when we debug this code we get RANDOMNESS for the array. In the same way, I want randomness for my buttons on form.
Thank you sir. sir i tried the code that u suggested.
I was missing the incremental character "n".
Tthe debug-able code is
flowlayoutpannel.controls.add(out(n)).
but it is not working as i wanted and ABOVE code is just to show the way i want 2 shuffle the BUTTONS.
Is there any simpler way to jst create an button array and randomize them with RANDOM() and adding to form.
My buddies says you are so stupid that u are working on this topic from last 20-25DAYS
There are quite some "shuffle" algorithms (search Fisher-Yates for example) and they are usually not difficult to implement. The EASIEST (imho) way, ist to use LINQ:
Dim r As New Random
Dim out = (From b In btnArray Order By r.Next Select b).ToArray
Maybe the question is not clear: Do you want to shuffle the POSITIONS of the buttons or do you want to shuffle the CONTENT (buttons) of the Array?
To set the position of the buttons randomly in the panel, instead of using n from 0 to 9 in the loop, you can use a random value from 0 to 9. Be sure you don't use the same value twice.
You don't need to use a cryptographically secure random number generator for that, nor do you need a separate class.
Private Shared rng As New Random()
Private Shared Function ShuffleArray(Of T)(arr() As T) As T()
Dim left = Enumerable.Range(0, arr.Length).ToList()
Dim result(arr.Length - 1) As T
For i = 0 To arr.Length - 1
Dim nextIndex = rng.Next(left.Count)
result(i) = arr(left(nextIndex))
left.RemoveAt(nextIndex)
Next
Return result
End Function