Browse to and open a file, then perform an action on it, and then browse and save output file

Question

I'm just starting to work with VB, and I'm a little lost. What I want to do is create a GUI whereby the use browses to a file, chooses it, and then an action (say a certain type of formatting is performed which generates an output file. Ideally, the same sort of browse function would be available for the user to choose where the output file is saved. Some of these actions I have been able to create, but getting them to work together is not happening yet. For instance, I created a Module to do the formatting:

Module Module1

    Sub Main()
        'Read all lines from MarcEdit-generated file
        Dim Lines() As String = IO.File.ReadAllLines("C:\PathToFile\in.txt")

        'Loop through each line
        For Each line As String In Lines
            'First search for any line that starts with '=246'
            If Left(line, 4) = "=246" Then
                'Check to see if the 9th digit is an 'a'
                If line(9) = "a" Then
                    Dim field246Cleaned As String = line.Substring(0, line.Length - 1)
                    'Print string and carriage return to out file
                    My.Computer.FileSystem.WriteAllText("C:\PathToFile\out.txt", field246Cleaned & vbCrLf, True)
                Else
                    My.Computer.FileSystem.WriteAllText("C:\PathToFile\out.txt", line & vbCrLf, True)
                End If

            Else
                Dim nonField246 As String = line
                My.Computer.FileSystem.WriteAllText("C:\PathToFile\out.txt", nonField246 & vbCrLf, True)
                Continue For

            End If
        Next


    End Sub

End Module

This reads the file, does the requisite formatting, and then creates a file with the changes. But the paths to the in and out files are static, as are the names of the files. It would be nice if I could create a GUI so the user could choose the name of the in file, and choose the location and name of the out file. I can create a form that has a browse button, so the user can choose the file:

Public Class Form1

    Public Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles txtFileDirectory.TextChanged

    End Sub

    Public Sub btnBrowse_Click(sender As Object, e As EventArgs) Handles btnBrowse.Click
        Dim myFileDlog As New OpenFileDialog()
        'look for files in the c drive
        myFileDlog.InitialDirectory = "C:\PathToFile\"
        'specifies what type of data files to look for
        myFileDlog.Filter = "All Files (*.*)|*.*" & "|Data Files (*.txt)|*.txt"
        'specifies which data type is focused on start up
        myFileDlog.FilterIndex = 2
        'Gets or sets a value indicating whether the dialog box restores the current  directory before closing.
        myFileDlog.RestoreDirectory = True
        'seperates message outputs for files found or not found
        If myFileDlog.ShowDialog() = DialogResult.OK Then
            If Dir(myFileDlog.FileName) <> "" Then
                'MsgBox("File Exists: " & myFileDlog.FileName, MsgBoxStyle.Information)
            Else
                MsgBox("File Not Found", MsgBoxStyle.Critical)
            End If
        End If
        'Adds the file directory to the text box
        'txtFileDirectory.Text = myFileDlog.FileName
        Dim testName = myFileDlog.FileName
        txtFileDirectory.Text = testName


    End Sub

    Public Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click

        Application.Exit()
    End Sub
End Class

Is there a way to use the browse function that I coded to find the filename, and then somehow use that filename as a parameter for the module to run? Ideally in the interface there would also be a browse function to set the path and name for the out file, too, which would be be passed to the module. Sorry if this is a vague or stupid question, I'm just starting out in VB!

Answer 1

Just place 2 read only text boxes with a button next to each. On the first button, do OpenFileDialog to get the file path. On the second button do BrowseForFolder dialog to set the output directory. And a button to start process.

Label: "Select file"        | TextBox: txtFile        | Button: btnOpenFile 
Label: "Select destination" | TextBox: txtDestination | Button: btnOpenFolder
                                                        Button: btnProcessFile

Refactor your method so it takes both, target file and destination folder

Sub ProcessFile(ByVal file as String, ByVal pathOut as String)
    'Read all lines from MarcEdit-generated file
    Dim Lines() As String = IO.File.ReadAllLines(file)

    'Loop through each line
    For Each line As String In Lines
        'First search for any line that starts with '=246'
        If Left(line, 4) = "=246" Then
            'Check to see if the 9th digit is an 'a'
            If line(9) = "a" Then
                Dim field246Cleaned As String = line.Substring(0, line.Length - 1)
                'Print string and carriage return to out file
                My.Computer.FileSystem.WriteAllText(Path.Combine(pathOut, "out.txt"), field246Cleaned & vbCrLf, True)
            Else
                My.Computer.FileSystem.WriteAllText(Path.Combine(pathOut, "out.txt"), line & vbCrLf, True)
            End If

        Else
            Dim nonField246 As String = line
            My.Computer.FileSystem.WriteAllText(Path.Combine(pathOut, "out.txt"), nonField246 & vbCrLf, True)
            Continue For

        End If
    Next


End Sub

This way, it is clearer for the user what is happening - here is intake, and here is output; correct? - correct - process. There are other things that you could do differently here but since you're learning I didn't refactor them.