I've looked all over the web for an answer to this, and been unable to replicate the bug myself, and somehow the textbox is appearing to be transparent and unable to be clicked; however it seems that if you set the "Text =" property to have a message in it, the textbox works fine.
I've looked at the properties and the code multiple times, nothing seems to be off. There's no calling of the textbox to be transparent, and nothing I've seen that would stop it from accepting user input.
The... "broken" code is:
Public Class GuessingGame
Const MIN As Integer = 1
Const MAX As Integer = 50
Private Sub btnCheckGuess_Click(sender As System.Object, e As System.EventArgs) Handles btnCheckGuess.Click
Randomize()
Static secretNumber As Integer = Int((MAX - MIN + 1) * Rnd() + MIN)
Static Count = 0
Dim guess As Integer
Count = Count + 1
guess = Val(Me.txtPlayerGuess.Text)
If guess < MIN Or guess > MAX Then 'invalid guess
MessageBox.Show("Guess out of range")
ElseIf guess = secretNumber Then
Me.lblMessage.Text = "You guessed it!" 'correct
MessageBox.Show(Count)
Else
Call GiveHint(secretNumber, guess)
End If
End Sub
Private Sub txtPlayerGuess_TextChanged(sender As System.Object, e As System.EventArgs)
'Clear the current answer when the user begins to type a new value
Me.lblMessage.Text = Nothing
End Sub
Private Sub GiveHint(firstNum As Integer, ByVal secondNum As Integer)
If firstNum > secondNum Then
MessageBox.Show("Too low.")
Else
MessageBox.Show("Too high.")
End If
End Sub
End Class
Anyone have any ideas as to what is causing this and how to fix it?
Related
The code below is a program to calculate the BMI using text boxes. I am having an issue however that when I clear one of the text boxes it will throw an exception and freeze the program. I was wondering if anyone had an answer on how to prevent this. I already tried setting my variables to 0 and 1 to see if that was the issue but it does not appear to be.
Private Sub tboxWeight_TextChanged(sender As Object, e As EventArgs) Handles tboxWeight.TextChanged
Weight = 0
Weight = Convert.ToInt64(tboxWeight.Text)
End Sub
Private Sub tboxHFeet_TextChanged(sender As Object, e As EventArgs) Handles tboxHFeet.TextChanged
Height_feet = 0
Height_feet = Convert.ToInt64(tboxHFeet.Text)
Get_BMI(1)
End Sub
Private Sub tboxHInch_TextChanged(sender As Object, e As EventArgs) Handles tboxHInch.TextChanged
Height_Inches = 0
Height_Inches = Convert.ToInt64(tboxHInch.Text)
Get_BMI(1)
End Sub
Private Sub tboxAge_TextChanged(sender As Object, e As EventArgs) Handles tboxAge.TextChanged
Age = Convert.ToDouble(tboxAge.Text)
End Sub
Function Get_BMI(ByVal j As Integer) As Double
BMI = (Weight / (Height_Inches + (Height_feet * 12) ^ 2) * 703)
tboxBMI.Text = Convert.ToString(BMI)
Exit Function
End function
It is because you set a textbox into an integer field, so when the textbox is empty it will throw exception because the textbox doesn't contain a number.
Try using If else statement for each textboxes.
String.IsNullOrEmpty function will be sufficient.
Good/Best practice says, you need to validate the data before performing calculation i.e. Get_BMI(). Below code snippet will help you.
Dim textBoxValue As String
If Not String.IsNullOrEmpty(textBoxValue) Then
If IsNumeric(textBoxValue) Then
End If
End If
I have 2 buttons and a DataGridView with 2 Columns (0 & 1).
The 1st button transfers a randomized cell from the Column(1) to a TextBox. Then, it stores that Cell in variable (a), plus the cell that opposites it in variable (b).
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Dim rnd As New Random
Dim x As Integer = rnd.Next(0, Form1.DataGridView1.Rows.Count)
Dim y As Integer = 1
Dim a As String = Form1.DataGridView1.Rows(x).Cells(y).Value
Dim b As String = Form1.DataGridView1.Rows(x).Cells(y - 1).Value
TextBox3.Text = a
End Sub
The 2nd button, however, is supposed to compare if another TextBox's text has the same string variable (b) has as Strings. Now, if so, then it has to display a certain message and so on...
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
If TextBox4.Text = b Then '<<< ISSUE HERE!
MsgBox("Correct! ^_^")
ElseIf TextBox4.Text = "" Then
MsgBox("You have to enter something first! O_o")
Else
MsgBox("Wrong! >,<")
End If
End Sub
The problem is that the variable (b) is surely not shared across the two "private" subs. And so, there is NOTHING to compare to in the 2nd button's sub! I presume that the solution here is to split the "randomization process" into a separate function, then execute it directly when the 1st button gets activated. Furthermore, that function's variables have to be SHARED somehow, and I certainly don't know how!
Thanks for Mr. Olivier, the code has been improved significantly! Yet, I still encounter a "wrong" comparison issue, somehow!
Dim RND As New Random
Dim x As Integer
Private Function GetCell(ByVal rowIndex As Integer, ByVal cellIndex As Integer) As String
Return Form1.DataGridView1.Rows(rowIndex).Cells(cellIndex).Value
End Function
Private Sub btnRoll_Click(sender As Object, e As EventArgs) Handles btnRoll.Click
x = RND.Next(0, Form1.DataGridView1.Rows.Count)
tbxRoll.Text = GetCell(x, 1)
End Sub
Private Sub btnSubmit_Click(sender As Object, e As EventArgs) Handles btnSubmit.Click
If tbxSubmit.Text = GetCell(x, 0) Then
MsgBox("Correct! ^_^")
ElseIf tbxSubmit.Text = "" Then
MsgBox("You have to enter something first! O_o")
Else
MsgBox("Wrong! >,<")
End If
End Sub</code>
Well, unbelievably, I read a guide about "comparison operations" in VB.net and tried out the first yet the most primal method to compare equality - which was to use .Equals() command - and worked like a charm! Thank God, everything works just fine now. ^_^
If tbxSubmit.Text.Equals(GetCell(x, 0)) Then
Alright now... This is going to sound weird! But, following Mr. Olivier's advise to investigate "debug" the code, I rapped the string I'm trying to compare with brackets and realized that it's been outputted after a break-line space! So, I used the following function to remove the "white-space" from both of the comparison strings! And it bloody worked! This time for sure, though. ^_^
Function RemoveWhitespace(fullString As String) As String
Return New String(fullString.Where(Function(x) Not Char.IsWhiteSpace(x)).ToArray())
End Function
If RemoveWhitespace(tbxSubmit.Text) = RemoveWhitespace(GetCell(x, 0)) Then
Turn the local variables into class fields.
Dim rnd As New Random
Dim x As Integer
Dim y As Integer
Dim a As String
Dim b As String
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
x = rnd.Next(0, Form1.DataGridView1.Rows.Count)
y = 1
a = Form1.DataGridView1.Rows(x).Cells(y).Value
b = Form1.DataGridView1.Rows(x).Cells(y - 1).Value
TextBox3.Text = a
End Sub
These fields can now be accessed from every Sub, Function and Property.
Of course Button3_Click must be called before Button2_Click because the fields are initialized in the first method. If this is not the case then you should consider another approach.
Create a function for the Cell access
Private Function GetCell(ByVal rowIndex As Integer, ByVal cellIndex As Integer) _
As String
Return Form1.DataGridView1.Rows(rowIndex).Cells(cellIndex).Value
End Function
And then compare
If TextBox4.Text = GetCell(x, y - 1) Then
...
And don't store the values in a and b anymore. If y is always 1 then use the numbers directly.
If TextBox4.Text = GetCell(x, 0) Then
...
One more thing: give speaking names to your buttons in the properties grid before creating the Click event handlers (like e.g. btnRandomize). Then you will get speaking names for those routines as well (e.g. btnRandomize_Click).
See:
- VB.NET Class Examples
- Visual Basic .NET/Classes: Fields
taking a VB class this term and I've been stumped on a problem I'm trying to figure out. We were asked to create a price calculator for movie titles at a movie rental place. Extra credit was storing them in a list and being able to print the list. I've gotten that far and now I want to go a step further and actually add titles to that list with an attached price. I figured the easiest way to do this would probably be with arrays but I don't have much experience working with arrays.
I was thinking something along the lines of storing each title(as its added) as well as the price in a variable to give a "Movie Title - $2.93" format in every line of the list box. For the sake of this problem I'm going to just post my full source code and that might make it easier to see what I'm trying to accomplish. ANY help would be MUCH appreciated. Thanks Stack overflow community!
A screenshot of my project can be viewed here: http://puu.sh/54SgI.jpg
Public Class Form1
'globablly declared because I might use them outside of btnAdd_Click event
Const decDiscount As Double = 0.9 '1-.10 discount = .9
Const decDVD As Decimal = 2D
Const decBlueray As Decimal = 2.5D
Const decDVDNew As Decimal = 3.25D
Const decBluerayNew As Decimal = 3.5D
Dim intCount As Integer
Dim decCost, decTotal As Decimal
Dim decDayTotal As Decimal
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
AcceptButton = btnAdd
End Sub
Private Sub chkDiscount_Click(sender As Object, e As EventArgs) Handles chkDiscount.Click
If chkDiscount.CheckState = 1 Then
chkDiscount.Enabled = False
End If
End Sub
Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
'Display error when no title entered
If txtAdd.Text = "" Then
MessageBox.Show("Please enter a movie title and select the appropriate item details.", "Complete details", MessageBoxButtons.OK, MessageBoxIcon.Error)
Else
listMovies.Items.Add(txtAdd.Text)
listMovies.SelectedIndex = listMovies.SelectedIndex + 1
End If
'update list
'clear txtbox
txtAdd.Text = ""
'Decision Statements to calculate correct price
If radDVD.Checked = True Then
decCost = CDec(decDVD.ToString("c"))
If chkNew.Checked = True Then
decCost = CDec(decDVDNew.ToString("c"))
End If
ElseIf radBlueray.Checked = True Then
decCost = CDec(decBlueray.ToString("c"))
If chkNew.Checked = True Then
decCost = CDec(decBlueray.ToString("c"))
End If
End If
If chkDiscount.Checked = True Then
decCost = CDec((decCost * decDiscount).ToString("c"))
End If
'display cost
txtCost.Text = CStr(CDec(decCost))
'calc total
decTotal = CDec(decTotal + decCost)
'display total
txtTotal.Text = CStr(CDec(decTotal))
'clear chkNew every item added to list
chkNew.CheckState = 0
End Sub
'Public so summary message box can access variable
Public Sub btnFinish_Click(sender As Object, e As EventArgs) Handles btnFinish.Click
'Add +1 to counter & update txtCounter
intCount = CInt(Val(intCount) + 1)
'add to day total
decDayTotal = CDec(Val(decDayTotal) + decTotal)
'Set Everything back to empty/enabled
chkDiscount.Enabled = True
chkDiscount.CheckState = 0
chkNew.CheckState = 0
txtAdd.Text = ""
txtCost.Text = ""
txtTotal.Text = ""
decTotal = 0
decCost = 0
'Instead of clearing radios each time, a more desirable result would be to have DVD always set back to the default checked radio
radDVD.Checked = True
radBlueray.Checked = False
listMovies.Items.Clear()
End Sub
Private Sub btnSummary_Click(sender As Object, e As EventArgs) Handles btnSummary.Click
If decTotal > 0 Then
MessageBox.Show("Please finish your current order before viewing a daily summary.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
Else
MessageBox.Show(("Your total cutomer count is: " & intCount) + Environment.NewLine + ("Your total sales today is: $" & decDayTotal), "Daily Summary", MessageBoxButtons.OK)
End If
End Sub
Private Sub btnRemove_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRemove.Click
listMovies.Items.Remove(listMovies.SelectedItem)
End Sub
I wont go very far here because you need to do the work. But, I would start with a class:
Public Class Movie
Public Title As String = ""
Public Cost As Decimal
' prevents you from adding a movie without critical info
Public Sub New(ByVal t As String, ByVal c As Decimal)
Title = t
Cost = c
End Sub
End Class
This would hold the info on one movie title rental, and keep it together (and can be added to in order to print exactly as you showed) . The plan (to the extent I understand what you are after) would be to create one of these for each movie rented and add it to a List(Of Movie) this is more appropriate than a Dictionary in this case.
To create a movie:
Dim m As New Movie(theTitle, theCost)
Things I would do:
You did a good job of declaring numerics as numbers. Fix the code that converts it to string and back to numeric. (edit your post)
You can use the Movie Class to populate the "Shopping Cart" listbox alone; at which point, listMovies.Items would BE the extra credit List. But it wouldnt hurt to use/learn about List (Of T). (BTW, does 'print' mean to paper, on a printer?)
What are you doing with chkDiscount? If they check it, you disable it (and never enable). Did you mean to disable the New Releases check? In THAT case, arent they really a pair of radios too?
Either way, CheckChanged is a better event for evaluating and there is no reason to manually set the check state for the user that happens by itself.
Check out List(of T) and HTH
A good thing to think about when doing assignments like this (particularly when learning your first language) is to think of the algorithm (the step you need to get to your goal).
1st, determine all the steps you need to get to your goal.
2nd, and I think this is the more import point for your question, figure out what order the steps need to be in (or better yet, what order they are most efficient in).
In your case I think that you are kind of ice skating up hill by adding the name of the movie to the list first, and then trying to add the price to the line later. Unless that kind of functionality was requested as part of the assignment I would require the user to enter both the name AND the price before accepting either (just like you do with the name currently). Like thus:
If txtAdd.Text <> "" AND txtCost.Text <> "" Then 'requiring both fields to not be null
''add moive code
Else
''MessageBox.Show("Yadda Yadda Yadda")
End If
I agree with Plutonix that creating a class, while overkill in your case, is a good idea, as it will give you practice for when it WILL be appropriate. Once you have that a class of Movie, you can then create lists of Movie(s) like this:
Dim MovieList as new List(of Movie)
So then, each time you press the btnAdd button, you can pass the values to a movie AND add it to the list.
Dim m As Movie
Dim MovieList as new List(of Movie)
Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
'Display error when no title entered
If txtAdd.Text <> "" And txtCost.Text <> "" Then
myMovie = New Movie(txtAdd.Text, txtCost.Text)
myMovieList.Add(myMovie)
listMovies.Items.Clear()
For Each X As Movie In myMovieList
listMovies.Items.Add(X.DisplayMovie)
Next
Else
MessageBox.Show("Please enter a movie title and select the appropriate item details.", "Complete details", MessageBoxButtons.OK, MessageBoxIcon.Error)
End If
'Other Code
End Sub
Note the line ListMovies.Items.Add(X.DisplayMovie) I added a function to the class Movie (seen below) so that it will do the formatting as you suggested.
Public Function DisplayMovie()
Return Title & " - $" & Cost
End Function
This will get you much of the way. Try to extrapolate what Plutonix and myself have explained to further refine your code. For instance, try encapsulating your adjusted price calculation in its own function so you can call it from anywhere.
I'm hoping you guys can help with a problem that should be simple to solve, I've just had issues finding a solution. In the program that I'm writing some of the textbox's have to be numeric between 1 and 10, and others just have to be numeric. Instead of coding each textbox to verify these parameters I decided to write methods for each of them. I'm having problems passing the arguments and getting it to function correctly. Included is some of my code that shows what I'm trying to accomplish.
Public Shared Sub checkforonetoten(ByVal onetoten As Double)
If (onetoten > 1 & onetoten < 10) Then
Else
MessageBox.Show("Please enter a Number between 1-10", "Error")
End If
End Sub
Public Shared Sub checkfornumber(numCheck As Double)
Dim numericCheck As Boolean
numericCheck = IsNumeric(numCheck)
If (numericCheck = False) Then
MessageBox.Show("Please enter a number", "Error")
End If
End Sub
Private Sub textboxS_TextChanged(sender As Object, e As EventArgs) Handles textboxS.TextChanged
Dim S As Double
S = textboxS.Text
checkfornumber(S)
checkforonetoten(S)
End Sub
One of your main problems is you're converting your text without validating it. You're also programming without the Options On to warn you of bad conversion techniques like you're using in the event handler.
The TryParse method would come in handy here:
Private Sub textboxS_TextChanged(sender As Object, e As EventArgs) Handles textboxS.TextChanged
Dim S As Double
If Double.TryParse(textboxS.Text, S) Then
checkforonetoten(S)
End If
End Sub
Since the TryParse method validates your text and sets the value to 'S', you only need to check the range.
Of course using NumericUpDown controls would make all this moot, since the values will always only be numbers and you can set the range on each one.
one way to structure it is to have one event procedure process the similar TB types:
Private Sub textboxS_TextChanged(sender As Object, e As EventArgs) _
Handles textbox1.TextChanged, textbox12.TextChanged, _
Handles textbox16.TextChanged
Dim S As Double
If Double.TryParse(Ctype(sender, TextBox).Text, S) Then
' or place the Check code here for all the TextBoxes listed above
checkforonetoten(S)
End If
End Sub
The plain numeric kind:
Private Sub textboxQ_TextChanged(sender As Object, e As EventArgs) _
Handles textbox2.TextChanged, textbox6.TextChanged
Dim S As Double
If Double.TryParse(Ctype(sender, TextBox).Text, S) = False Then
MessageBox.Show("Please enter a number", "Error")
End If
End Sub
Rather than calling a function and passing the current TextBox from events (which is fine), have 2 or 3 events process them all. The point is adding/moving the Handles clause to a common event procedure (be sure to delete the old ones).
If you do decide to call a common function, dont do anything in the events (you still have one per TB) and do it all in the common proc:
Private Sub textboxS_TextChanged(sender As Object, e As EventArgs) _
Handles textboxS.TextChanged
checkforonetoten(Sender)
End Sub
private Sub checkforonetoten(tb As Textbox)
Dim S As Double
If Double.TryParse(tb.Text, S) Then
' your check for 1 - 10 on var S
else
' error: not a valid number
End If
end sub
Also:
If (onetoten > 1 & onetoten < 10) Then
should be:
If (onetoten > 1) AndAlso (onetoten < 10) Then
I have tried converting using CInt, TryParse, Convert.Int32, etc but nothing worked. I just need to display the total votes of the candidated when a button btnVote is clicked and display the result when I click btnResult. I've tried searching on the net also but still no luck so I came up to this website and hopefully I could solve my problem with my program in VB.net
Below is my code:
Public Class Presidential_Election
Private Sub btnVote_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnVote.Click
If cboCandidates.Text = "NOLI" Then
lblNoli.Text = Integer.Parse(lblNoli.Text) + 1
ElseIf cboCandidates.Text = "VAL" Then
lblVal.Text = (CInt(lblVal.Text) + 1).ToString
ElseIf cboCandidates.Text = "LESTER" Then
lblLester.Text = CInt(lblLester.Text) + 1
ElseIf cboCandidates.Text = "GWAPO" Then
lblGwapo.Text = CInt(lblGwapo.Text) + 1
End If
End Sub
Private Sub btnResult_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnResult.Click
lblNoli.Visible = True
lblVal.Visible = True
lblLester.Visible = True
lblGwapo.Visible = True
End Sub
End Class
I would set an integer counter for each candidate. Set these to 0 and then increment them as they receive a vote. When you display the results just bind the text of the label to its respective counter and make it visible. This way, you don't have to keep referencing label.text.
If you haven't set the label text to be 0 at the beginning, using CInt would definitely throw an error. You have two options :
set all labels text to 0 and keep using CInt, or
use Val()
Example :
lblGwapo.Text = Val(lblGwapo.Text) + 1