calculating program in visual basic - vb.net

I trying to make program in visual basic in Text Changed event that when enter value the text box the program will store that value and when delete that value and enter new value it will use the first value and Compares with the new value if the new value > from the first value Decreases the new value from the first value (new value-first value) and if the new value < from the first value it will Decreases the first value from new value (first value - new value) and the The result another text box
Dim f As String
Private Sub TextBox2_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox2.TextChanged
If TextBox2.Text > f Then
TextBox18.Text = TextBox2.Text - f
f = (TextBox2.Text)
End If
I make this code it work but when the new value is (10) or Larger its not working

Try the following:
Dim f As String
Private Sub TextBox2_Leave(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox2.Leave
If not string.isnullOrEmpty(TextBox2.Text) Then
If CDbl(TextBox2.Text) > CDbl(f) Then
TextBox18.Text = CStr(CDbl(TextBox2.Text) - CDbl(f))
f = TextBox2.Text
End If
End If
End Sub

Related

How can I get ten numbers and displays the biggest and lowest one?

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

Get value of multiple created controls at runtime VB.NET

I can get the value of a single control that has been created at run time, that control is a DateTimePicker, but i can't get the values of multiple controls. how do i do it?
code:
This is where i add the DateTimePicker with every click at run time.
Private Sub btnAddTime_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAddTime.Click
Dim Time As New DateTimePicker()
Dim count As Integer = GroupBox1.Controls.OfType(Of DateTimePicker)().ToList().Count
Time.Location = New Point(9, (23 * count) + 22)
Time.Size = New Size(150, 20)
Time.Format = DateTimePickerFormat.Time
Time.ShowUpDown = True
Time.Name = "DateTimePicker" & (count + 1)
GroupBox1.Controls.Add(Time)
End Sub
And this is where i get the values of the controls.
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Dim i As Integer = 0
For Each cntrl In Form3.GroupBox1.Controls
Dim dt As DateTimePicker = Form3.GroupBox1.Controls.Item("DateTimePicker" & (i + 1))
If DateTime.Now.ToString = dt.Value Then
MsgBox("P")
End If
Next
End Sub
I can only get the the value of a created control if only i specified it in the code, i think i can't get the right Name of the control. I'm trying to make the program to read every value of the control in another form while the Timer ticks. help?
Try this:
For Each cntrl In Form3.GroupBox1.Controls
If TypeOf cntrl Is DateTimePicker Then
If DateTime.Now.ToString = cntrl.Value Then
MsgBox("P")
End If
End If
Next

Public variable used for form opening not feeding through to from

Having some issues getting a form to populate based on a variable determined in current form.
I have a search result form that has a datagrid with all results, with an open form button for each row. When the user clicks this, the rowindex is used to pull out the ID of that record, which then feeds to the newly opened form and populates based on a SQL stored procedure run using the ID as a paramter.
However, at the moment the variable is not feeding through to the form, and am lost as to why that is. Stored procedure runs fine if i set the id within the code. Here is my form open code, with sci
Public Class SearchForm
Dim Open As New FormOpen
Dim data As New SQLConn
Public scid As Integer
Private Sub Search_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim sql As New SQLConn
Call sql.SearchData()
dgvSearch.DataSource = sql.dt.Tables(0)
End Sub
Private Sub dgvSearch_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles dgvSearch.CellContentClick
Dim rowindex As Integer
Dim oform As New SprinklerCardOpen
rowindex = e.RowIndex.ToString
scid = dgvSearch.Rows(rowindex).Cells(1).Value
TextBox1.Text = scid
If e.ColumnIndex = 0 Then
oform.Show()
End If
End Sub
End Class
The form opening then has the follwing:
Private Sub SprinklerCard_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Populate fields from SQL
Try
Call Populate.SprinklerCardPopulate(ID)
cboInsured.Text = Populate.dt.Tables(0).Rows(0).Item(1)
txtAddress.Text = Populate.dt.Tables(0).Rows(0).Item(2)
txtContactName.Text = Populate.dt.Tables(0).Rows(0).Item(3)
txtContactPhone.Text = Populate.dt.Tables(0).Rows(0).Item(4)
txtContactEmail.Text = Populate.dt.Tables(0).Rows(0).Item(5)
numPumps.Value = Populate.dt.Tables(0).Rows(0).Item(6)
numValves.Value = Populate.dt.Tables(0).Rows(0).Item(7)
cboLeadFollow.Text = Populate.dt.Tables(0).Rows(0).Item(8)
cboImpairment.Text = Populate.dt.Tables(0).Rows(0).Item(9)
txtComments.Text = Populate.dt.Tables(0).Rows(0).Item(10)
Catch ex As Exception
MsgBox(ex.ToString & "SCID = " & ID)
End Try
End Sub
Set the ID variable in the form before you open it.
If e.ColumnIndex = 0 Then
oform.ID = scid
oform.Show()
End If

read single word from listbox vb

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)

VB.NET Count line number in textbox

I use Fileystemwatcher to watch a certain folder on our network share and wan't to count the lines in a textbox.
I have 2 richtextboxes, the first one will display the line number and the second one displays the change/deleted/renamed file.
I am able to display the total of lines in a label, but also want to show the line numbers in a richtextbox, but the problem is that it adds the number to the current, it needs to add the number on a new line.
Hopefully the image will explain.
Private Sub textFolderActiviteit_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles textFolderActiviteit.TextChanged
textFolderActiviteit.SelectionStart = textFolderActiviteit.Text.Length
textFolderActiviteit.SelectionLength = 0
textFolderActiviteit.ScrollToCaret()
textFolderActiviteit.Focus()
Dim currentLineIndex As Integer = textFolderActiviteit.GetLineFromCharIndex(textFolderActiviteit.SelectionStart)
Me.Label2.Text = String.Format("{0}", currentLineIndex + 1)
Me.textLineCount.Text = String.Format("{0}", currentLineIndex + 1 & vbCrLf)
End Sub
Private Sub textLineCount_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles textLineCount.TextChanged
textLineCount.SelectionStart = textLineCount.Text.Length
textLineCount.SelectionLength = 0
textLineCount.ScrollToCaret()
textLineCount.Focus()
End Sub
Maybe I'm misunderstanding the question, but couldn't you just put the VbCrlf before the line number?
Me.textLineCount.Text = String.Format("{0}", vbCrLf & (currentLineIndex + 1).ToString())