Loading text from a file into a textbox

Question

I'm trying to place text from a text file in a textbox, but the textbox remains blank after the code executes. How can I fix this?

Dim fileno1 As Integer = FreeFile()
FileOpen(fileno1, "C:\Users\main computer\Desktop\vb test\gyn-obs-D.txt", OpenMode.Input, OpenAccess.Read, OpenShare.Shared)
Dim y As Boolean = 0
Dim c = 0
TextBox1.Text = "1"
Do While Not EOF(fileno1)
    c += 1
    Dim txt As String = LineInput(fileno1)
    Debug.WriteLine(txt)
    Dim inputString As String = txt

    TextBox1.Text = txt
    If c = 40 Then
        y = 1
        Exit Do
    End If
    write1(inputString, y)
Loop
FileClose(fileno1)

edit: i added this class but still something wrong

' of course these next two are at top Imports System Imports System.IO

Class Test
    Public Shared Sub Main()
        Try
            ' Create an instance of StreamReader to read from a file.
            ' The using statement also closes the StreamReader.
            Using sr As New StreamReader("TestFile.txt")
                Dim line As String
                ' Read and display lines from the file until the end of
                ' the file is reached.
                Do
                    line = sr.ReadLine()
                    If Not (line Is Nothing) Then
                        Console.WriteLine(line)
                    End If
                         textbox1.text=line  
                Loop Until line Is Nothing
            End Using
        Catch e As Exception
            ' Let the user know what went wrong.
            Console.WriteLine("The file could not be read:")
            Console.WriteLine(e.Message)
        End Try
    End Sub
End Class

vb 6 uses handles "#" ,EOF is end of file,to know when file reached the end — md nth, Jul 10 '13 at 19:34
BTW this is VB.Net code, using the VB6 backward compatibility libraries, not pure VB6. I recommend using `Option Strict On` in all VB.Net code. I would also recommend giving `c` an explicit type - `Integer` — MarkJ, Jul 10 '13 at 19:53
@mdnth - Using System.IO.File.ReadAllLines simplifies your code tremendously. I left you an answer to consider. — tinstaafl, Jul 11 '13 at 05:06

score 3 · Answer 1 · answered Jul 11 '13 at 05:01

3

How about

TextBox.Text = System.IO.File.ReadAllText("C:\Users\main computer\Desktop\vb test\gyn-obs-D.txt")

If that is too long

TextBox.Text = System.IO.File.ReadAllText("C:\Users\main computer\Desktop\vb test\gyn-obs-D.txt").Substring(0,1000)

answered Jul 11 '13 at 05:01

Mark Lakata

19,989
5
106
123

score 0 · Answer 2 · answered Jul 10 '13 at 19:41

0

TextBox1.Text = txt

This line will effectively errase what you had in the text box with contents of txt. I am assuming the 40th line of your input file is a blank line. That is way the textbox appears empty.

You should do something in the lines of:

TextBox1.Text = TextBox1.Text + txt + Environment.NewLine

Some pointers on your current code:

Check up on Option Strict. It can be enabled on the properties window of your project and enables higher quality of produced code.
Functions like EOF and the likes seems like old VB functions ported to .NET. Look into Using the System.IO namespace to read text from a file

answered Jul 10 '13 at 19:41

Hemario

140
9

If he is in fact using VB 6 rather than (which seems more likely), this answer is not going to be particularly helpful. There's no `Environment.NewLine` in VB 6, it's the `vbNewLine` constant. And there's no `Option Strict` either, although `Option Explicit` should be at the top of all source files. – Cody Gray - on strike Jul 10 '13 at 19:44
The original question was marked vb.net, but has been changed in the meantime. The fact remains that the contents of TextBox1.Text is being overwritten in each loop. `vbNewLine` instead of `Environment.Newline` and we're good to go. – Hemario Jul 10 '13 at 19:51
I'm not criticizing your answer, I know the question is/was unclear. Just adding some extra info if it is VB 6. – Cody Gray - on strike Jul 10 '13 at 19:51
its not vb6 for sure, its vb 2010,and i used book by wrox,and the 40 line is not empty – md nth Jul 10 '13 at 20:01
1

Time to throw that book away, @mdnth. It's well over 10 years out of date. It's teaching you how to write VB 6 code, which only works in VB 2010 for backwards compatibility reasons. You should *not* be learning VB 6 in the year 2013. Get yourself a new book on VB.NET, preferably version 2010 or 2012. – Cody Gray - on strike Jul 10 '13 at 20:04
You'll need to elaborate what it is exactly what you're trying to accomplish. – Hemario Jul 10 '13 at 20:09

score 0 · Answer 3 · edited May 23 '17 at 12:32

Simply do this,

Private Sub Command1_Click()
Open "C:\Users\reserve.txt" For Input As #1
Dim filesize As Integer
filesize = LOF(1)
textbox1 = Input(filesize, #1)
Close #1
End Sub

Or,

Private Sub Command1_Click() 
Dim variable1 As String 
Open "C:\Users\reserve.txt" For Input As #1 
Input #1, variable1 
textbox1.Text = variable1 
Close #1 
End Sub

Or,see How to display the text file while clicking the button

tinstaafl · Answer 4 · 2013-07-11T05:12:50.010

Here's a simple way in VB.net:

    Try
        For Each s As String In System.IO.File.ReadAllLines("C:\Users\main _
                                      computer\Desktop\vb test\gyn-obs-D.txt")
            TextBox1.AppendText(s + vbNewLine)
        Next
    Catch ex As Exception
        MessageBox.Show(ex.Message)
    End Try

This way if there are any changes to make or lines you don't want you have the option.

score -1 · Answer 5 · edited Jun 21 '19 at 05:56

-1

I figured it out, when I output data into textbox too fast , it'll not appear

edited Jun 21 '19 at 05:56

Community

1
1

answered Jul 29 '13 at 16:47

md nth

119
1
1
6

score -1 · Answer 6 · answered Mar 14 '17 at 08:42

-1

'Easy Code.....................From Juman Dim b As String b = System.IO.File.ReadAllText("File Address Here")

            MessageBox.Show(b.ToString())

answered Mar 14 '17 at 08:42

Juman

1

Loading text from a file into a textbox

6 Answers6

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