How to Create a Random Line Selector in Visual Basic

Submitted by Yorkiebar on Sunday, October 6, 2013 - 05:42.

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Introduction: Welcome to my tutorial on how to create a random line selector from a word document. Steps of Creation: Step 1: First we want to create a form with... Textbox1 - File Path Textbox2 - Chosen line Button1 - Browser for file path Button2 - Get random line Step 2: Now lets do the button1 function - selecting a file path...

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim fo As New OpenFileDialog
    fo.Filter = "Text Files|*.txt"
    fo.FilterIndex = 1
    fo.ShowDialog()
    If (Not fo.FileName = Nothing) Then
        TextBox1.Text = fo.FileName
    End If
End Sub

We simply create a new file browser and make it so it will only allow the user to select a text file. We then check if it is a correct file (otherwise they have closed the browser) and if so it will make textbox1.text the file path. Step 3: Next we want to make the random line code. First we want to check the file path still exists and then read all the lines in the file and add them all to our list lines variable. We then get a random number and set the text of textbox to the random line.

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    If (Not TextBox1.Text = Nothing) Then
        If (My.Computer.FileSystem.FileExists(TextBox1.Text)) Then
            Dim lines As New List(Of String)
            Using sr As New StreamReader(TextBox1.Text)
                While sr.Peek <> -1
                    lines.Add(sr.ReadLine())
                End While
            End Using
            Dim rand As Random = New Random()
            Dim r As Integer = rand.Next(lines.Count())
            TextBox2.Text = lines(r)
            rand = Nothing
            r = Nothing
             lines = Nothing
        End If
    End If
End Sub

Project Complete! That's it! Below is the full source code and download to the project files.

Imports System.IO
Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim fo As New OpenFileDialog
        fo.Filter = "Text Files|*.txt"
        fo.FilterIndex = 1
        fo.ShowDialog()
        If (Not fo.FileName = Nothing) Then
            TextBox1.Text = fo.FileName
        End If
    End Sub
 
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        If (Not TextBox1.Text = Nothing) Then
            If (My.Computer.FileSystem.FileExists(TextBox1.Text)) Then
                Dim lines As New List(Of String)
                Using sr As New StreamReader(TextBox1.Text)
                    While sr.Peek <> -1
                        lines.Add(sr.ReadLine())
                    End While
                End Using
                Dim rand As Random = New Random()
                Dim r As Integer = rand.Next(lines.Count())
                TextBox2.Text = lines(r)
                rand = Nothing
                r = Nothing
                lines = Nothing
            End If
        End If
    End Sub
End Class

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