I have this application with a list box. When a button is clicked, certain things from my db is supposed to display. Along with the display comes column headers!!! It comes in the form of "{itemID = SW934, quantity = 10..." and so on. How do I get rid of the "{" and the column header??? Here is my current code:
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'MICROLANDDataSet.Orders' table. You can move, or remove it, as needed.
Me.OrdersTableAdapter.Fill(Me.MICROLANDDataSet.Orders)
'TODO: This line of code loads data into the 'MICROLANDDataSet.Inventory' table. You can move, or remove it, as needed.
Me.InventoryTableAdapter.Fill(Me.MICROLANDDataSet.Inventory)
'TODO: This line of code loads data into the 'MICROLANDDataSet.Customers' table. You can move, or remove it, as needed.
Me.CustomersTableAdapter.Fill(Me.MICROLANDDataSet.Customers)
End Sub
Private Sub btnOut_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOut.Click
Dim query1 = From OUT In MICROLANDDataSet.Inventory
Where OUT.quantity <= 10
Order By OUT.description Descending
Select OUT.itemID, OUT.quantity, OUT.description
lstOutput.DataSource = query1.ToList
lstOutput.SelectedItem = Nothing
End Sub
End Class
Thanks guys. Any help is VERY WELCOME.
The problem is that query1 is an In-Memoery Queue Of Anonymous. In other words, it is a enumeration of objects of an undefined type. One way to get around this, is to concatenate your results into one string.
Select OUT.itemID & OUT.quantity & OUT.description
and make query1 a List(Of String) (You can format the string any way you wish.)
Another option is to designate one of the fields as a display field.
lstOutput.DisplayMember="Description"
Related
Public Class SalesReport
Private Sub SalesReport_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'loginDataSet.BillInfo' table. You can move, or remove it, as needed.
Me.BillInfoTableAdapter.Fill(Me.loginDataSet.BillInfo)
Me.ReportViewer1.RefreshReport()
End Sub
End Class
I think you miss some Code you didn't assign and datasource to your report , Try add this line to your code :
Me.ReportViewer1.DataSources.Add(Me.loginDataSet.BillInfo)
i given code like this:
Private Sub txtemployeename_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtemployeename.KeyDown
keyval = e.KeyData
Dim keyData As System.Windows.Forms.Keys = e.KeyData
If keyData = Keys.Down Then
LstEmployee.Visible = True
LstEmployee.Focus()
End If
End Sub
while i am cliking down arrow first time that is not focusing to listbox,second time am clicking down arrow that is focusing..also once cursor come to tha list box,if i clik enter that should be displayed in text box..for that i given code like this..
Private Sub LstEmployee_Enter(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LstEmployee.Enter
txtemployeename.Text = LstEmployee.SelectedItem
End Sub
but this is not working properly..for loading list box i given code like this:
Private Sub txtemployeename_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtemployeename.KeyPress
Dim s As String = txtemployeename.Text
LstEmployee.Visible = True
loadlistbox(LstEmployee, "select Ename from EmployeeMaster_tbl where Ename LIKE'%" & s & "%' ")
End Sub
You should rely on the KeyUp event rather than on the KeyDown one. Also for the ListBox you just need the SelectedIndexChanged event. Additionally, your code has quite a few errors (wrong query (-> you don't need to call your DB every time to order the items in the ListBox), relies on SelectedIndex rather than on SelectedItem...). Here you have an updated version:
Private Sub txtemployeename_KeyUp(sender As Object, e As System.Windows.Forms.KeyEventArgs) Handles txtemployeename.KeyUp
Dim s As String = txtemployeename.Text
LstEmployee.Visible = True
Dim list = LstEmployee.Items.Cast(Of String)()
Dim query = From item As String In list Where item.Length >= s.Length AndAlso item.ToLower().Substring(0, s.Length) = s.ToLower() Select item
If (query.Count > 0) Then
Dim newItems = New List(Of String)()
For Each result In query
newItems.Add(result)
Next
LstEmployee.Items.Clear()
For Each newItem In newItems
LstEmployee.Items.Add(newItem)
Next
End If
End Sub
Private Sub LstEmployee_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles LstEmployee.SelectedIndexChanged
txtemployeename.Text = LstEmployee.SelectedItem
End Sub
The code above checks for occurrences (i.e., if the whole string in the txtemployeename matches (caps do not matter) the starting substring of, at least, one element in LstEmployee) every time a new character is introduced in txtemployeename. The ListBox is updated with these ocurrences. txtemployeename displays the name of the selected item in LstEmployee.
I hope that this will be enough to help you to build the code required to deliver the exact functionalities you are after.
NOTE: bear in mind that this approach (deleting/adding Items) is incompatible with cases where the ListView is populated with a DataSource. If you rely on a DataSource you would have to update this code accordingly.
NOTE2: the proposed approach deals with the elements in the ListView. You have to introduce these elements at the start from whatever source you are using; this code only updates existing information (items in the ListBox). Also bear in mind that this code is expected to be corrected to match your exact requirements; for example: list has to be associated with the total number of items (the ones retrieved from your datasource at the start), not with the current ones (as displayed in the code; it just represents a simplified version of the problem): every time a new population occurs all the items (other than the target ones) are deleted and thus the ListBox does not represent a reliable source. Example to understand this: at the start, you have "aaaa", "bbbb", "cccc"; if you type "a", all the elements except "aaaa" would be deleted. If you type now "b" and consider the actual elements in the ListBox, no change would occur as far as the only element is "aaaa"; you would have to consider all the original elements (which, as suggested via comment, might be stored at the start in an array/list of strings).
I am new to Visual Basic. I have installed Microsoft Visual Studio 2010. Created a new Windows Form Application. As an example, I made a simple program which will ask the end user to input 2 numbers and allow them to either add them or subtract the second number from the first one and display the output in a Textbox.
Now, I added another Subroutine which would be executed automatically when the Windows Form loads. This would calculate the width of the output Textbox and the Form Width and display at the bottom.
This is how the code looks like right now:
Public Class Form1
' Run this Subroutine initially to display the Form and Text box width
Private Sub Form_Load()
Label5.Text = TextBox3.Width
Label7.Text = Me.Width
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim a As Integer
Dim b As Integer
a = TextBox1.Text
b = TextBox2.Text
TextBox3.Text = a + b
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim a As Integer
Dim b As Integer
a = TextBox1.Text
b = TextBox2.Text
TextBox3.Text = a - b
End Sub
End Class
While everything works correctly for the addition and subtraction, it does not display the Form and output Textbox width in the Windows Form.
I think, Form_Load() is not executing properly.
I also tried, Form_Activate() but that did not work either.
Once I am able to do this, I would like to extend this concept to resize the output Textbox along with the Form resize. However, for the purpose of understanding I wanted to see if I can execute Form_Load() successfully.
Thanks.
Form_Load doesn’t execute. For now, it’s just any other method. In order to tell VB to make this method handle the Load event, you need to tell it so:
Private Sub Form_Load(sender As Object, e As EventArgs) Handles MyBase.Loasd
Label5.Text = TextBox3.Width
Label7.Text = Me.Width
End Sub
(And add the required parameters for the event.)
A few other remarks:
Ensure that Option Strict On is enabled in your project options at all times. This will make the compiler much stricter with your code and flag more errors. This is a good thing since these errors are potential bugs. In particular, your code is very lax with conversions between different data types, these should be made explicit.
Initialise variables when you declare them, don’t assign a value in a separate statement. That is, write this:
Dim a As Integer = Integer.Parse(TextBox1.Text)
(Explicit conversion added as well.)
If you want to make a control fill the form, you can just set its Dock property appropriately in the forms editor, instead of having to program this manually.
You need to add the Handle so the app executes it automatically:
Private Sub Form_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
'...
End Sub
Okay this is what I have so far. I have a form that needs to load a file externally and populate the combobox. I can get that part if I use a button, but I don't want to use a button. I want it to populate when the form loads for the first time. The below code does not accomplish this, it doesn't even try to load it. I put break points in this code but it never breaks. I am thinking that the combobox isn't loaded yet and the program doesn't try.
Any help would be nice.
Private Sub mortCalMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'sets listview values
mortBox.SelectedIndex = 0
Dim rdr As StreamReader = File.OpenText("mortgageTypes.txt")
While Not rdr.EndOfStream
Dim line As String = rdr.ReadLine()
mortBox.Items.Add(line)
End While
rdr.Close()
End Sub
Comment out this line:
'mortBox.SelectedIndex = 0
You can't set the index on an empty list.
I have some code where I am trying to use variables in a tabpage. The first tabpage only has one text box for user entry (miles.text) and a button to do a calculation: traveltime = mileage/speed. The value from miles.text is stored into a variable called mileage while the speed used is stored in a variable called speed (me.speedtextbox.text).
Ordinarily, doing val(variable.text) works like a charm and it's not doing it in this case. When the user enters 100 for the mileage, it should be divided by 65 (the number in the database) and, therefore, the answer should be 1.53 hours. In my case, I'm getting "infinity" and whenever I do anything else with the variable, I get "when casting from a number, the value must be a number less than infinity." But it is! It's only 65 and I double-checked that the dataset said that too, which it does. Not sure why I am getting this error...thank you!
Public Class Form1
Private Property Traveltime As Decimal
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'fooDataSet.testdata' table. You can move, or remove it, as needed.
Me.TestdataTableAdapter.Fill(Me.foouDataSet.testdata)
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim mileage As Integer
Dim speed As Integer
mileage = Val(miles.Text)
speed = Val(Me.SpeedTextBox.Text)
traveltime = mileage / speed
txttraveltime.text = Traveltime.ToString
End Sub
Private Sub txtrate_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txttraveltime.TextChanged
End Sub
End Class
So I did a test program where it did only one thing and that was to simply read one data column in a one row database and store it to a local variable and multiply it by 1.60 except now I am getting "reference to a non-shared member requires an object reference" and it doesn't seem to recognize Me.Speed when I declare it. What am I doing wrong?
Public Class Form1
Dim Speed As Object
Dim Me.Speed As New Speed
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Me.Speed = CDec(fooDataSet.testdataRow.Item("speed"))*1.60
Speedtextbox.text = Me.Speed.tostring
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'fooDataSet.testdata' table. You can move, or remove it, as needed.
Me.TestdataTableAdapter.Fill(Me.fooDataSet.testdata)
End Sub
End Class
Before you do anything else, you should do the following:
Open the project's properties (right-click on the Project, then select Properties)
Click on the Compile tab (left-hand side)
Select All Configurations from the dropdown menu
Select On from the Option Explicit menu.
Select On from the Option Strict menu.
Save the project
This will more than likely cause a lot of errors to be displayed, but fixing these errors will substantially improve your application's health.
Now, that that is done, the following code will fix the problems in the button click:
Dim mileage As Integer
Dim speed As Integer
If IsNumeric(Me.Miles.Text) Then
mileage = CInt(Me.Miles.Text)
End If
If IsNumeric(Me.SpeedTextBox.Text) Then
speed = CInt(Me.SpeedTextBox.Text)
End If
If speed <> 0 Then
Traveltime = CDec(mileage / speed)
Else
Traveltime = 0
End If
txtTravelTime.Text = Traveltime.ToString
However, the code as you have it will produce correct results, so there must be something else amiss. Try the above first and if there are still issues, you can update your question with the details.
I would implement the calculation in a separate class and then use object-binding. Here is how the travel time calculator would look like:
Imports System.ComponentModel
Public Class TraveltimeCalculator
Implements INotifyPropertyChanged
Private _miles As Double
Public Property Miles() As Double
Get
Return _miles
End Get
Set(ByVal value As Double)
If _miles <> value Then
_miles = value
OnPropertyChanged("Miles")
OnPropertyChanged("Traveltime")
End If
End Set
End Property
Private _speed As Double
Public Property Speed() As Double
Get
Return _speed
End Get
Set(ByVal value As Double)
If _speed <> value Then
_speed = value
OnPropertyChanged("Speed")
OnPropertyChanged("Traveltime")
End If
End Set
End Property
Public ReadOnly Property Traveltime() As Double
Get
Return If(_speed = 0.0, 0.0, _miles / _speed)
End Get
End Property
#Region "INotifyPropertyChanged Members"
Public Event PropertyChanged As PropertyChangedEventHandler _
Implements INotifyPropertyChanged.PropertyChanged
Private Sub OnPropertyChanged(ByVal propertyName As String)
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
End Sub
#End Region
End Class
In Visual Studio, add a data source in the Data Sources panel. Choose "Object" and then select the TraveltimeCalculator (it has to be compiled, before you can do that). Now you can drag the speed, mileage and travel time fields from the data sources panel to your form. All the wire-up will happen automatically. VS automatically inserts a BindingSource and a navigator into your form. You will not need the navigator and can safely remove it. The only thing you still have to do is to add the following code in the form load event handler or in the form constructor:
Private Sub frmTravelTime_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
TraveltimeCalculatorBindingSource.DataSource = New TraveltimeCalculator()
End Sub
When you enter speeds and mileages, the travel time textbox will automatically be updated. Non-numeric entries will automatically be rejected and all the text-number conversions happen automatically.
I discovered what the problem was.
To store a field from a one-line database to a local variable for calculations, apparently it has to happen in the form1_load event, after the dataadapter fill statement, like so:
Me.TestdataTableAdapter.Fill(Me.foouDataSet.testdata)
speed = Me.fooDataSet.testdata(0).speed
and just DIM speed as Decimal after the Public Class line. The same could be done for any other field you want to work with in a similar kind of single datarow:
yourvarname = Me.yourdatasetname.yourtablename(0).the_database_field_you_want_to_fetch
(Wow! Did I just write something textbooky? LOL)
Then, after the button click, to do a calculation, it is:
traveltime = CDec(miles.Text/ speed)
txttraveltime.Text = traveltime.ToString
making sure to DIM traveltime as Decimal.
Works! The problem was the (0) to indicate row 0 (because it's only one row.) Thank you everyone for your help, especially Competent_Tech. I learned something and I'm happy that I could get back to you guys and share.