You've created a jagged array (an array of arrays). When you do this each element points to another array. The array's initially aren't created. I think this is why you get the error. Take this for example

    Dim data(5)() As String
    data(0) = New String() {"Data1", "Data2", "Data3"}

    Console.WriteLine(data(0)(0))

    ' The next line will throw an error because the 2nd element
    ' doesn't point to an array yet.
    Console.WriteLine(data(1)(0))

What's probably happening is you are only reading x number of rows, so only the first x elements have been initialized properly. Trying to read beyond x will throw an error. You could initialize all the elements first like so:

    For i As Integer = 0 To data.Length - 1
        data(i) = New String() {}
    Next

Or you can just make sure you don't read beyond the number of lines read.

I believe the UserControl is firing it's mouseleave event when the mouse goes over the label or picturebox. This is normal. When the event fires you might be able to just check the mouselocation and if it's within the bounds of your control, exit the method. You could also try to get around the problem by doing all the drawing yourself instead of using a picturebox and label. **EDIT** The reason it pops up is because of the second loop in this method 'pctBoxVerkleinern'. Also I believe your going to have some threading issues because you can't start a thread once it's been aborted. In the mouseenter and leave events you need to create a new instance of the thread and then start it.

Yup, here is a simple example.

Private Sub Form1\_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    ' Add a column to the listview
    ListView1.Columns.Add("Name")

    ' Create two groups
    ListView1.Groups.Add("Group1", "Group1")
    ListView1.Groups.Add("Group2", "Group2")

    ' Add two items and assign them to the desired group
    ListView1.Items.Add("Test Group1").Group = ListView1.Groups("Group1")
    ListView1.Items.Add("Test Group2").Group = ListView1.Groups("Group2")

    ' Add another item differently and give it a group
    ListView1.Items.Add(New ListViewItem("Test Group1 again", ListView1.Groups("Group1")))

    ListView1.View = View.Details

    ' Basically you need to know that the groups collection is where you 
    ' add groups to the listview

    ' I've showed two different ways you can add an item and assign it to a group
    ' This should give you an idea how to work with groups
End Sub

I showed you code to dymanically create textboxs, is that how these textbox's were created or were they created at design time? Controls created at design time are given a default name, however, controls created at runtime are not. When you create the textbox you need to set it's name property. This is one reason why 'Name' may not be returning anything.

Me.ActiveControl will give you a reference to the control that has focus. The problem I'm guessing is your code resides in a button click event. If you click the button it gets focus so Me.ActiveControl.Name will return the buttons name. What exactly are you trying to do? Can you describe the program a little?

That's what IntelliSense is for :) Also the MSDN library is a big help.

The listbox contains objects which could be anything. ListBoxUpgrade.SelectedItem(i) will return whatever text the ToString method returns. For most objects this is the type of object it is. Because you've bound your listview you actually have a listview full of DataRowView objects. This is why the ToString method is returning System.Data.DataRowView. If you want to get the corresponding text of the item (the text being displayed in the listbox) you can use the GetItemText method.

    For Each obj As Object In ListBox1.SelectedItems
        Console.WriteLine(ListBox1.GetItemText(obj))
    Next

There is no design time support for creating control arrays. Here is some code that demonstrates a few different approaches.

Public Class Form1
' An array of textbox's
Private ControlArray As New List(Of TextBox)

Private Sub Form1\_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    ' Here I am adding TextBox's that already exist on my form to the array
    With ControlArray
        .Add(TextBox1)
        .Add(TextBox2)
        .Add(TextBox3)
    End With

    ' Loop through each textbox in the array
    For Each tb As TextBox In ControlArray
        MsgBox(tb.Name)
    Next

    ' Access a textbox by index
    MsgBox(ControlArray(1).Name)

    ' Here I am creating textboxes dynamically and adding them
    ' to the array
    For i As Integer = 0 To 2
        ' Create a textbox
        Dim tb As New TextBox
        ' Set it's position
        tb.Location = New Point(20, 10 + i \* 30)
        ' Set it's width
        tb.Width = 100

        ' Add the textbox to the array
        ControlArray.Add(tb)

        ' Add the textbox to the form
        Me.Controls.Add(tb)

        ' Add handlers for the GotFocus and LostFocus events
        AddHandler tb.GotFocus, AddressOf TextBox\_GotFocus
        AddHandler tb.LostFocus, AddressOf TextBox\_LostFocus
    Next

    ' Here I've looped through the forms controls and found
    ' all the textboxes and added them to the array
    ' This is a good approach if you have many controls you added at
    ' design time but don't want to manually add each one to the array.
    ' The desired event handlers can also be dynamically added this way
    For Each ctrl As Control In Me.Controls
        Dim tb As TextBox = TryCast(ctrl, TextBox)
        If tb IsNot Nothing Then
            ControlArray.Add(tb)
        End If
    Next
End Sub

' Handles the textboxes GotFocus event
' I've handled the controls I created at design time by including them after the handles keyword
Private Sub TextBox\_GotFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.GotFocus, TextBox2.GotFocus, TextBox3.GotFocus
    ' tb is a reference to the textbox that raised this event
    Dim tb As TextBox = DirectCast(sender, TextBox)
    tb.BackColor = Color.Wheat
End Sub

' Handles the textboxe

This is how I might go about it. Hope it gives you the right idea.

    Const directoryPath As String = "C:\\test"   ' The directory to look in

    Dim desiredFiles As New List(Of String)     ' List of files we're looking for
    With desiredFiles       ' Note I didn't use file extensions.  Change that if you'd like.
        .Add("File1")       ' but you'll need to tweak the code below if you do.
        .Add("File2")
    End With

    ' METHOD 1

    ' Create a DirectoryInfo object for the desired directory
    ' to look in.
    Dim info As New IO.DirectoryInfo(directoryPath)

    ' Get all the \*.doc files in the directory
    For Each file As IO.FileInfo In info.GetFiles("\*.doc")
        ' The contains method is case sensitive.  If you want a case-insentive
        ' search you can add the desired file names in all lower or uppercase and then use the
        ' ToLower or ToUpper methods on the file name
        If desiredFiles.Contains(IO.Path.GetFileNameWithoutExtension(file.Name)) Then
            ' The file name was found in our list
            MsgBox("Directory contained file: " & file.Name)
        End If
    Next

    ' METHOD 2
    For Each file As String In desiredFiles
        If IO.File.Exists(IO.Path.Combine(directoryPath, file & ".doc")) Then
            MsgBox("Directory contained file: " & file)
        End If
    Next

You'd write something like this

text1.text = ListBox1.Items.Item(2).ToString()

The array holding the items is zero based, which means the 3rd item is really the 2nd element in the array.

You can easily fix a controls size by overriding SetBoundsCore. It looks like this.

Protected Overrides Sub SetBoundsCore(ByVal x As Integer, ByVal y As Integer, ByVal width As Integer, ByVal height As Integer, ByVal specified As System.Windows.Forms.BoundsSpecified)
    Const fixedWidth As Integer = 50
    Const fixedHeight As Integer = 50

    MyBase.SetBoundsCore(x, y, fixedWidth, fixedHeight, specified)
End Sub

I know changing the size back in the resize event will also work, but doing it that way actually allows the control's size to be changed and then it quickly changes it back. Overriding SetBoundsCore will prevent the change from ever occurring.

Guffa, I think that regular expression would fail to properly parse something like "ThisIsATest" because it wouldn't pick up on two capital letters next to one another. I think something like this would be required to find the word boundaries "([A-Z]|[a-z])(?=[A-Z])". Using a replace of "$1 ".

All controls can contain other controls, but I assume you want design time support like the panel has. Do do that add this line of code just before the class declaration.

<Designer("System.Windows.Forms.Design.ParentControlDesigner,System.Design", GetType(IDesigner))> _

I found a way to cope with 'th', 'st', 'nd' and 'rd'. It's not that pretty but if you wrap it up into a function you've got a workable solution. It would be nice if you could just ignore characters, then you could use something like "d##MMMMyyyy" where # would be a character that's ignored. However, I couldn't find anything in the documentation that would lead me to believe that's possible. Anyway here you go.

    ' Valid date formats
    Dim validFormats As String() = {"d'st'MMMMyyyy", "d'nd'MMMMyyyy", "d'rd'MMMMyyyy", "d'th'MMMMyyyy"}
    Dim myDate As Date = Date.ParseExact("1stDecember1993", validFormats, Globalization.CultureInfo.CurrentCulture, Globalization.DateTimeStyles.None)

Your original post showed no spaces for the date...it was 7thNovember1993. If that's not the case just add appropriate spaces into the formatting strings and it should work.

dataReader("name") is the short version of dataReader.Item("name"). You can do this because the property 'Item' is the default property.

The article supplied contains a library that will create a proper datasource from a multi-dimensional array. Just download the .dll and add a reference to it. You can then use it like this:

    Dim test(2, 2) As String
    test(0, 1) = "SomeData"
    test(0, 2) = "SomeOtherData"
    DataGridView1.DataSource = New Mommo.Data.ArrayDataView(test)

You can accept a multidimensional array like this.

Private Function GetRow(ByVal data(,) As Double, ByVal row As Integer) As Double()

End Function

The function also returns a 1-dimensnial array. All the function needs now is to get the values from the array and return them as 1-dimensional array.

Also you could use a regular expression to do the splitting. It will allow you to remove all the white space between values so you only get the actual text. Take a look at this.

    Dim value As String = "A      B     C"

    Dim regex As New System.Text.RegularExpressions.Regex("\\s+")
    For Each s As String In regex.Split(value)
        Console.WriteLine(s)
    Next

Because your using spaces as your delimiter it was probably hard to notice but the values that will be contained in 'sites' are not spaces, they are empty strings. Take a look at this code:

    Dim value As String = "A,,B,C"

    For Each s As String In value.Split(","c)
        Console.WriteLine(s)
    Next

You'll notice the values returned by the split function are 'A','','B','C' where '' is an empty string. It doesn't return the delimiter. In your loop you should test that the string is not empty.

sk8er_boy287 wrote:

However, if you can prove that StringBuilder is better than simple string concatenation, you get an A+.

If you need to build a string in a loop the stringbuilder is FAR more efficient then normal string concatenation. I've run into the problem before and learned the hard way. Actually I learned about it a while back using VB6, but VB6 didn't have a nice StringBuilder so I figured out another way around it. A simple example will show the difference. Do I get an A+? :)

Public Class Form1
Private Sub TestStringConcatenation(ByVal loops As Integer, ByVal myText As String)
Dim s As String = ""
For i As Integer = 0 To loops
s &= myText
Next
End Sub

Private Sub TestStringBuilder(ByVal loops As Integer, ByVal myText As String)
    Dim sb As New System.Text.StringBuilder
    For i As Integer = 0 To loops
        sb.Append(myText)
    Next
End Sub

Private Sub Button1\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Const LOOPS As Integer = 1000
    Dim myText As String = New String("A"c, 200)
    Dim sw As New Stopwatch

    sw.Start()
    TestStringConcatenation(LOOPS, myText)
    sw.Stop()
    Console.WriteLine("Normal string concatenation took {0} ticks", sw.ElapsedTicks)

    sw.Reset()
    sw.Start()
    TestStringBuilder(LOOPS, myText)
    sw.Stop()
    Console.WriteLine("String builder took {0} ticks", sw.ElapsedTicks)
End Sub

End Class

As for the code the OP posted, what's funny about it is how much extra useless code the person used to return a string. All that was needed was a simple line

Return "Current date and time is " + DateTime.Now.ToString()

As someone already mentioned the original code writer probably learned that is was more efficient to use the stringbuilder if you are going to append text to a string. Unfortunatly they didn't use it correctly and didn't really grasp when it's appropriate to use it. I ran a test to see what method performed best. In this case normal string concatenation seemed to out perform stringbuilder. Here is my code I used to see the performance of each method.

Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Const TRIALS As Integer = 1000
Const LOOPS As Integer = 1000