Is there a way to extract a variable from a subroutine in vb .net? or how do I declare custom event handlers and trigger them in a linked fashion? - vb.net

Question

I am trying to build this file copy utility in VB.Net, and I have this window:
The current folder button opens up a folder browser dialog, and I save the selected path from the dialog to a string variable which I then pass to a function. The function adds all files and directories present in that folder to the current folder listbox.
Now I need this filepath for the all files checkbox, which when triggered lists all the subdirectories and their contents in the currentfolder listbox.
Is there any way I can extract that filepath variable dynamically without hardcoding it? Or can I create custom event handlers and trigger them inside the current folder button handler?
Here is my code:
Public Class Form1
Public Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim FB As FolderBrowserDialog = New FolderBrowserDialog()
Dim srcpath As String
Dim flag As Integer = 1
FB.ShowDialog()
FB.ShowNewFolderButton = True
If (DialogResult.OK) Then
srcpath = FB.SelectedPath()
End If
listfiles(srcpath)
End Sub
Public Function listfiles(srcpath As String)
Dim dir As DirectoryInfo = New DirectoryInfo(srcpath)
Dim dirs As DirectoryInfo() = dir.GetDirectories()
Dim d As DirectoryInfo
Dim files As FileInfo() = dir.GetFiles()
Dim file As FileInfo
For Each file In files
CurrentFolderListBox.Items.Add(file.Name)
Next
For Each d In dirs
CurrentFolderListBox.Items.Add(d)
Next
'If CheckBox1.Checked = True Then
' CheckBox1_CheckedChanged(sender, New System.EventArgs())
'End If
End Function
Public Sub CheckBox1_CheckedChanged(sender As Object, e As EventArgs) Handles CheckBox1.CheckedChange
Dim item As DirectoryInfo
For Each i As DirectoryInfo In CurrentFolderListBox.Items
item = i
Next
End Sub
Any help would be most appreciated.

Answer 1

Well, for the list side lbox, and the right side lbox?
Why not fill each list box with a data source? You can have 1, or 2, or even 5 columns of data. The ListBox can display TWO of the columns.
So, VERY often a list box will have two values. the "value" based on what you select (often a PK database row value), and then you have the "text" value for display.
from FoxPro, ms-access, vb.net, and even asp.net?
A list box traditional has had the ability to "store" a set of values for your selection.
So, why not just put out the file list to a on the fly "data structure". You can quite much use a struct, a class or whatever.
However, might as well use a data table, since listbox supports "binding" to a table.
So, in the ListBox settings, you have these two settings:
so above is our "display"
And then set the "value" to the FULL file name like this:
So now we can say create a form like this:
So, our code to select the "from folder" can look like this:
Private Sub cmdSelFrom_Click(sender As Object, e As EventArgs) Handles cmdSelFrom.Click
Dim f As New FolderBrowserDialog
If f.ShowDialog = DialogResult.OK Then
txtFromFolder.Text = f.SelectedPath
ListBox1.DataSource = GetFileData(txtFromFolder.Text)
End If
End Sub
Public Function GetFileData(sFolder As String) As DataTable
Dim rstData As New DataTable
rstData.Columns.Add("FullFile", GetType(String))
rstData.Columns.Add("FileName", GetType(String))
' get all files from this folder
Dim folder As New DirectoryInfo(sFolder)
Dim fList() As FileInfo = folder.GetFiles
For Each MyFile As FileInfo In fList
Dim OneRow As DataRow = rstData.NewRow
OneRow("FullFile") = MyFile.FullName
OneRow("FileName") = MyFile.Name
rstData.Rows.Add(OneRow)
Next
Return rstData
End Function
so, we setup a two column "thing" (in this case a data table).
We fill it with our two values (FileName and FullFile).
So, we now have this:
I have selected two files on the left side, and thus we get this:
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
For Each MySel As DataRowView In ListBox1.SelectedItems
Debug.Print(MySel.Item("FileName"))
Debug.Print(MySel.Item("FullFile"))
Next
End Sub
OutPut:
a.pdf
C:\Test2\a.pdf
b.pdf
C:\Test2\b.pdf
We could even include say file size in that table. But the "basic" concept here is that we can store + save data items into the list box, and that REALLY makes the code simple, since the list box now has JUST the file for display, but also enables us to have the full path name also.