Imports System.IO
Public Class Form1
Private paths() As String = {"x"}
Private Sub ListBox1_DoubleClick(ByVal sender As Object, ByVal e As _
  System.EventArgs) Handles ListBox1.DoubleClick
Process.Start(paths(ListBox1.SelectedIndices(0) + 1))
 
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles Button1.Click
Dim dInitPath As DirectoryInfo
Dim lSearchpattern As List(Of String)
Dim lFiles As List(Of FileInfo)
ListBox1.Items.Clear()
 
lSearchpattern = New List(Of String)
lSearchpattern.Add("*" & ComboBox1.Text & "*" & "*" & TextBox1.Text & "*" & "*" _
  & TextBox2.Text & "*" & "*" & TextBox3.Text & "*" & "*.pdf" & "*")
dInitPath = New IO.DirectoryInfo("server")
lFiles = searchFiles(dInitPath, lSearchpattern)
For Each fiFile As FileInfo In lFiles
ListBox1.Items.Add(fiFile.Name)
ReDim Preserve paths(paths.Length)
paths(paths.Length - 1) = fiFile.FullName
Next
End Sub
Private Function searchFiles(ByVal dPath As DirectoryInfo, ByVal _
lSearchpattern As List(Of String)) As List(Of FileInfo)
Dim lFiles As List(Of FileInfo) = New List(Of FileInfo)
For Each sPattern As String In lSearchpattern
For Each fiFile As FileInfo In dPath.GetFiles(sPattern, _
  SearchOption.AllDirectories)
lFiles.Add(fiFile)
Next
Next
Return lFiles
End Function