Randomly select Treeview Items

Hello! :wave:
It's me again... :blush:

In my app I have a sub named RandomAllGenie which is supposed to select or identify a childnode from a treeview. based on that, it needs to set a picture accordingly in the picturebox.

How can I achieve that ¿

VB Code:

Private Sub RandomAllGenie()
        Dim RandGen As New Random
        Dim GenStr As String
 
        Randomize()
        Dim RandNum As Integer = RandGen.Next(1, (NumFiles + 1))
        GenStr = DirName & "\" & GenArr(RandNum)
        picRealGenie.Image = Image.FromFile(GenStr)
 
        picPreview.Image = Image.FromFile(GenStr)
        picPreview.Refresh()
        ApplyGenie()
    End Sub
 
   Private Sub frmGenie_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
        TreeGenie()
        LoadReg()
        RandomAllGenie()
       
    End Sub
 
  Private Sub TreeGenie()
        Dim FolderNode As TreeNode
        Dim FilePath As String
        Dim FolderPath As String
        Dim Xtension As String
        Dim diNext As DirectoryInfo
 
        For Each FolderPath In Directory.GetDirectories(DirName, "*")
            FolderNode = trGenie.Nodes.Add(Path.GetFileName(FolderPath))
 
            For Each FilePath In Directory.GetFiles(FolderPath)
                Xtension = IO.Path.GetExtension(FilePath)
 
                If Xtension = ".bmp" OrElse Xtension = ".jpg" OrElse Xtension = ".JPG" OrElse Xtension = ".jpe" OrElse Xtension = ".gif" Then
                    FolderNode.Nodes.Add(Path.GetFileName(FilePath))
                    NumFiles = NumFiles + 1
                    If AutoGenieReg = "Automatic" Then
                        GenArr(NumFiles) = Path.GetFileName(FilePath)
                    End If
                End If
            Next
        Next
        lblNumFiles.Text = NumFiles.ToString() & " Items In Repository"
    End Sub

Any help would be GreaTlY appreciated :thumb:

So whats the problem?

You're getting mixed up between the System.Random class and the Runtime method Randomize. They each have NOTHING to do with the other. Randomize is intended to be used in conjunction with the Rnd Runtime function, but I'd suggest you stick with the Random class. You should create one Random object rather than a new one each time you call the function. Create a class level variable like this:

VB Code:

Private RandGen As New Random(CInt(Date.Now.Ticks Mod Integer.MaxValue))

By seeding the Random with a time based value you should get a different psuedo-random sequence each time. If you use no seed or the same seed each time then the same psuedo-random sequence will be generated every time. Now that you have a Random object, you just call Next each time you need random number. You would call it like this:

VB Code:

myRandomNumber = Me.RandGen.Next(0, Me.GenArr.Length)

Note that the value returned will be >= to the minimum specified (zero) and < than the maximum (the length of the array). You would substitute Count for Length if GenArr is a collection, but the name suggests an array.

Its not actually necessary to manually seed the Random class, the constructor does that itself based on the system time anyway. See MSDN.

Quote:

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Originally Posted by wossname

Its not actually necessary to manually seed the Random class, the constructor does that itself based on the system time anyway. See MSDN.

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Well there you go. I didn't know that, but it does make sense. I even just read the relevant help topic to confirm it, not that I didn't have faith of course. :D

Quote:

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Originally Posted by jmcilhinney

If you use no seed... each time then the same psuedo-random sequence will be generated every time.

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Who's spouting that rubbish?