Open a file, read text and display in a listbox

[Plumebee]

Hi, I am very new to programming and have just started to use Visual Basic 2005 Express Edition. I am trying to read from a text file to draw a rectangles and lines. However to begin I'm trying to get the information to show in a listbox so that I know the application is reading the file correctly. I seem to be able to open the file but it doesn't display anything in the listbox.

Dim FileName As String
        Dim reader As System.IO.StreamReader
 
        uieOpenFileDialog.InitialDirectory = "C:\"
        uieOpenFileDialog.Title = "Open a File"
        uieOpenFileDialog.Filter = "Text Files(*.txt)|*.txt|All Files(*.*)|*.*"
        uieOpenFileDialog.ShowDialog()
 
        MsgBox(FileName)
        Dim DidWork As Integer = uieOpenFileDialog.ShowDialog()
        If DidWork = DialogResult.Cancel Then
            MsgBox("Cancel Button Clicked")
        Else
            FileName = uieOpenFileDialog.FileName
            MsgBox(FileName)
        End If
 
        reader = System.IO.File.OpenText(uieOpenFileDialog.FileName)
        Dim shape As String
        Dim code As Integer
 
        Try
            Me.ListBox1.Items.Clear()
 
            Do While reader.Peek <> -1
                shape = reader.ReadLine
                If shape = "Rectangle" Then
                    Select Case code
                        Case 1
 
                            rect.X = Convert.ToInt32(reader.ReadLine)
                            rect.Y = Convert.ToInt32(reader.ReadLine)
                            rect.Width = Convert.ToInt32(reader.ReadLine)
                            rect.Height = Convert.ToInt32(reader.ReadLine)
 
                            ListBox1.Items.Add()
 
 
                        Case 2
                            rect.X = Convert.ToInt32(reader.ReadLine)
                            rect.Y = Convert.ToInt32(reader.ReadLine)
                            rect.Width = Convert.ToInt32(reader.ReadLine)
                            rect.Height = Convert.ToInt32(reader.ReadLine)
 
                            ListBox1.Items.Add
 
                    End Select
                Else
                End If
            Loop
        Catch
            Me.ListBox1.Items.Add("file is empty")
        End Try
        reader.Close()
    End Sub

The error code I'm receiving is: Error 1 Argument not specified for parameter 'item' of 'Public Function Add(item As Object) As Integer'.

[Teme64]

You should add something to ListBox when you're using Add method (lines 36 and 45). Change lines to following:

ListBox1.Items.Add("Code=" & code &  ", Rect.X=" & rect.X & ", Rect.Y=" & rect.Y & ", Rect.Width=" & rect.Width & ", Rect.Height=" & rect.Height)
 

and you'll see what you read from your file.

[rpicilli]

Hi friend.

Give a example of the line you have in this file text this way I could help you.

Your code is missing information. For example:

shape = reader.ReadLine
If shape = "Rectangle" Then
Select Case code *******You never put any value in code always is 0 (zero)
Case 1
****Convert the same value in this 4 lines. This will give you a DOT on screen
rect.X = Convert.ToInt32(reader.ReadLine)
rect.Y = Convert.ToInt32(reader.ReadLine)
rect.Width = Convert.ToInt32(reader.ReadLine)
rect.Height = Convert.ToInt32(reader.ReadLine)

ListBox1.Items.Add()


Case 2
rect.X = Convert.ToInt32(reader.ReadLine)
rect.Y = Convert.ToInt32(reader.ReadLine)
rect.Width = Convert.ToInt32(reader.ReadLine)
rect.Height = Convert.ToInt32(reader.ReadLine)

***here you are adding nothing to the listbox1
ListBox1.Items.Add

End Select
Else
End If

Put here a line of the text file that I'll help you.

Rogerio