Load CSV to Listview including Subitems

Hello all!

Using Visual Basic 2008, I Want to load a csv file to Listview.

I am new to LINQ, and had some great performance increase in using LINQ (compared to loops) when loading a csv file to a single column Listview.

Example Code:

Code:

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Dim items() As ListViewItem = (From line In IO.File.ReadAllLines(thefiletoread) Where line.Length <> 0 Select New ListViewItem(RTrim(line.ToUpper))).ToArray
ListView2.Items.AddRange(items)

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altought, i have not found any way to do the exact same thing, but in a multiple column Listview.

I do not wish to use loops, since LINQ syntax works so well.

any of you guys have an idea?

I see you mention performance, but I don't really see how LINQ could be quicker in this case. A loop will almost always give significantly better performance when compared to a LINQ method.

If you can provide a file layout and the target listview column setup, I'm sure someone can give you a quick example of how to do this.

Hello!

Thanks for your answer....

The input text file is a TAB separated file. I have no idea upon import how much columns is needed in the Listview.

By Default my List view has a single column. If i detect the presence of one or more TAB character, i programmatically add the column to add the data split from the original input String.

So let's say my input file is: (note replaced TABs by Spaces since the website inputbox does not allow for TABs)

Banana Fruit Yellow
Apple Fuit Red
Cocumber Vegetable Green

Note1: I do not know the quantity of TAB separator Characters (if any), but all lines contain the same number of column. (from 0 to 83 approx)
Note2: My file can contain up to 100 000 lines

Currently, my code is:

Code:

---

Dim items() As ListViewItem = (From line In IO.File.ReadAllLines(thefiletoread) Where line.Length <> 0 Select New ListViewItem(RTrim(line.ToUpper))).ToArray
ListView2.Items.AddRange(items)

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This is quick, but has no column Logic...

So i would need to

-Import the file Line by line
-Scan the first line as string and determine quantity of TAB separator Characters
-Add the Missing columns to Listview
-Split the Input Line String
-Loop trough all Portions of the Splitted string to add to listview Item variable (not adding to Listview for now)
-Continue looping trough all line of input document
-Detect End if File
-Add listview Item Variable to Listview with addrange

Do you agree?

I really have the feeling that importing using Linq is quicker than loops... but i may be wrong.
I will have to test this new logic and compare the time it takes.
My past experience of importing big text files could take up to 5 minutes (with no multi-column analysis), when similar Ling import would take less than 30 sec.

Here is base code from other web site: (http://bytes.com/topic/visual-basic-...view-add-items)

Code:

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Dim i As ListViewItem = ListView1.Items.Add("First portion from file")
i.SubItems.Add("Second portion from file")
i.SubItems.Add("third portion from file")

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Here is a quick example that should give some insight:

Code:

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    Private Sub LoadDataToListview()

        Dim filePath As String = "C:\myfile.txt"
        Dim streamReader As New IO.StreamReader(filePath)
        Dim streamText As String
        Dim listViewItem As ListViewItem

        While Not streamReader.EndOfStream

            streamText = streamReader.ReadLine()

            If Not String.IsNullOrEmpty(streamText) Then


                If Not ListView1.Columns.Count = 0 Then
                    '
                    'Add listview items
                    '
                    listViewItem = New ListViewItem(streamText.Split(ControlChars.Tab))
                    '
                    'Do additional work on values here
                    '
                    ListView1.Items.Add(listViewItem)
                Else
                    '
                    'Populate Column Headers
                    '
                    For Each value As String In streamText.Split(ControlChars.Tab)
                        ListView1.Columns.Add(value)
                    Next
                End If

            End If

        End While

        streamReader.Dispose()


    End Sub

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