vb.net statusbar text doesn't show - vb.net

Question

I have a code that searches for words in documents and fills a Listview with the found documents. Because the process can be rather lengthly I put a warning in the statusbar.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim foundList As Boolean
Dim docImage As VariantType
Dim PresetName As String
ListView1.Items.Clear()
ToolStripLabel1.Text = "Searching your documents, please wait."
Try
For Each row As DataRowView In CheckedListBox1.CheckedItems
SearchRegX = row("RegX")
Next
If TextBoxFreeText.Text <> "" Then
'look for a space in the search criteria, meaning there are more words
Dim counter As Integer = TextBoxFreeText.Text.IndexOf(" ")
If counter <> -1 Then
'more words were entered to search
Dim varSplit As Object
varSplit = Split(TextBoxFreeText.Text, " ")
'if more than two words are entered our regex doesnt work, so we exit the sub
If varSplit.length > 2 Then
MsgBox("Your search criteria are to complex, use a maximum of two words",, Title)
Exit Sub
End If
iWords = NumericUpDown1.Value
SearchRegX = "(?i)\b(?:" + varSplit(0) + "\W+(?:\w+\W+){0," + iWords + "}?" + varSplit(1) + "|" + varSplit(1) + "\W+(?:\w+\W+){0," + iWords + "}?" + varSplit(0) + ")\b"
Else
'just one word was entered
SearchRegX = "(?i)\b" + TextBoxFreeText.Text + "\b"
End If
End If
If SearchRegX = "" Then
MsgBox("No Keyword was selected",, Title)
Exit Sub
End If
If ListBox1.SelectedIndex > -1 Then
For Each Item As Object In ListBox1.SelectedItems
Dim ItemSelected = CType(Item("Path"), String)
SearchFolder = ItemSelected
'check if the folder of the archive still exists
If (Not System.IO.Directory.Exists(SearchFolder)) Then
Dim unused = MsgBox("The archive " + SearchFolder.Substring(SearchFolder.Length - 5, Length) + " was not found",, Title)
Continue For
End If
Dim dirInfo As New IO.DirectoryInfo(SearchFolder)
Dim files As IO.FileInfo() = dirInfo.GetFiles()
Dim file As IO.FileInfo
docImage = ImageList1.Images.Count - 1
Dim items As New List(Of ListViewItem)
For Each file In files
Dim filename As String = file.Name.ToString
If file.Extension = ".pdf" Or file.Extension = ".PDF" Then
foundList = PDFManipulation.GetTextFromPDF2(SearchFolder + filename, SearchRegX)
If foundList = True Then
If ListView1.FindItemWithText(filename.ToString) Is Nothing Then
items.Add(New ListViewItem(New String() {"", filename.ToString, SearchFolder.ToString}, docImage))
End If
End If
End If
Next
ListView1.Items.AddRange(items.ToArray)
Next
ToolStripLabel1.Text = ListView1.Items.Count.ToString + " Documents found."
Else
MsgBox("No archive was selected",, Title)
End If
SearchRegX = ""
SearchFolder = ""
'now save the search word to our textfile
PresetName = TextBoxFreeText.Text
If PresetName <> "" Then
AddSearchWord()
End If
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
Somehow the text doesn't show in the statusbar before the process starts.
What should I change?
I thought about a BackgroundWorker showing an image like waiting but the BackgroundWorker doesn't work because inside my Sub I call a function elsewhere.

Answer 1

This happens because the status strip control is not rendered properly before the pending workload is finished. To do so, you can refresh the status strip manually:
StatusStrip1.Refresh()
That is, if your only goal is to set the text. If you thought about running the code in the background so that the form is still responsive to user input, you'll need asynchronous programming using System.Threading.Tasks or System.Threading.Thread to run the code as a seperate thread. Be aware though that you may face difficulties when trying to access controls outside of the main thread.

Answer 2

Add Async to your button handler declaration:
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Now change your call to PDFManipulation.GetTextFromPDF2() so that it is within a Task:
Await Task.Run(Sub()
foundList = PDFManipulation.GetTextFromPDF2(SearchFolder + filename, SearchRegX)
End Sub)
If foundList = True Then
...