Checkboxes in any Cell in a ListView

The built-in Checkbox functionality for ListViews will put a checkbox at the beginning of each row. I only needed to put the check box at the beginning of certain rows. The following posting show a simply way to achieve this requirement. I did not use this method exactly as it is shown, but it was definitely a good start:

http://bytes.com/topic/visual-basic-net/insights/880195-putting-checkboxes-any-cell-listview

Getting Selection and Arrow keys to behave right with a ListBox in the.NET Compact Framework

I had a form in a Window Mobile application that contains a Label and a ListBox. I wanted the ListBox to behave according to the Windows Mobile UI guidelines where you click on an item with the stylus and it is automatically selected. I used the SelectedIndexChanged event to implement this behavior and it worked fine when an item was selected with the stylus. However, with all of the different kinds of devices, many of them have partial or even full keyboards and at the very least they have a joypad or equivalent, my users were wanting to use the arrow keys to navigate to a specific item in the list and then press the enter button (never using the stylus). Unfortunately, the SelectedIndexChanged event is fired anytime the ListBox’s selected item is change (by stylus or keys) and since using the arrow keys usually requires scrolling through several items before getting to the item you want, the next item in the list is always selected (be it the one you want or not). I could not find a way in the .NET Compact Framework to get the ListBox to work like I wanted.

My solution was to replace the ListBox with a ListView. Change the View property to Details and change the Activation property to OneClick. Then use the ItemActivate event provided by the ListView instead of the SelectedIndexChanged event. You also have to add at least one Column to the ListView, and you can optionally set HeaderStyle to None to get rid of the column header and make the ListView look just like a ListBox.

Exporting ListView to CSV File in VB.NET

I have posted an article on copying a ListView to the Windows Clipboard, but I have also found it useful to export a ListView directly to a .CSV file (comma separated value file). The process to go from a ListView to the clipboard or to a CSV file is similar.

There are number of rules for creating a CSV file. Here is a good place to look if you want to see them all. I have simplified the process to a few rules that will work for most cases. I put quotes around all values and column names. Technically, this is not required, but by putting them around all cases eliminates the need to determine if you need them or not. I also replace any quote in the data with a double quote.

Public Function ExportListViewToCSV(ByVal filename As String, ByVal lv As ListView) As Boolean

Try

' Open output file
Dim os As New StreamWriter(filename)
 
' Write Headers

For i As Integer = 0 To lv.Columns.Count - 1
    ' replace quotes with double quotes if necessary
    os.Write("""" & lv.Columns(i).Text.Replace("""", """""") & """,")
Next

os.WriteLine()

' Write records
For i As Integer = 0 To lv.Items.Count - 1
   For j As Integer = 0 To lv.Columns.Count - 1
       os.Write("""" & lv.Items(i).SubItems(j).Text.Replace("""", """""")+ """,")
    Next

    os.WriteLine()

Next

os.Close()

Catch ex As Exception
' catch any errors
Return False
End Try

Return True

End Function

You may want to get the file name from the user and automatically open the file in Excel too. Here is an example of how to do that:

Public Sub TestExportToCSV()

Dim dlg As New SaveFileDialog
dlg.Filter = "CSV files (*.CSV)|*.csv"
dlg.FilterIndex = 1
dlg.RestoreDirectory = True

If dlg.ShowDialog = Windows.Forms.DialogResult.OK Then

  If ExportListViewToCSV(dlg.FileName, ListView1) Then

      Process.Start(dlg.FileName)

  End If

End If

End Sub

Copy ListView to Clipboard in VB.NET, C#, and VB6

It is often useful to be able to copy the contents of a ListView to the Windows Clipboard. I have written a function for VB.NET, C#, and VB6 called CopyListViewToClipboard that will copy the contents of a ListView (in Details mode) to the Windows Clipboard. Additional functions are also available for a ListBox control here. The column headers will be the first row and the items in the listview will be the remaining rows. To make the copied data more compatible with applications like Excel, a tab character is placed between items in a row and a carriage return/linefeed is placed at the end of the row.

Here is an example ListView with some data in it:



Here is what is copied to the clipboard and then to Excel:




VB.NET:

Imports System.text

...


Public Sub CopyListViewToClipboard(ByVal lv As ListView)

   Dim buffer As New StringBuilder   

   For i As Integer = 0 To lv.Columns.Count - 1
       buffer.Append(lv.Columns(i).Text)
       buffer.Append(vbTab)
   Next

   buffer.Append(vbCrLf)

   For i As Integer = 0 To lv.Items.Count - 1
       For j As Integer = 0 To lv.Columns.Count - 1
           buffer.Append(lv.Items(i).SubItems(j).Text)
           buffer.Append(vbTab)
       Next
       buffer.Append(vbCrLf)
   Next

   My.Computer.Clipboard.SetText(buffer.ToString)

End Sub

C#

using System.Text;

...


public void CopyListViewToClipboard(ListView lv)
{
     StringBuilder buffer = new StringBuilder();

     for (int i = 0; i < lv.Columns.Count; i++)
     {
        buffer.Append(lv.Columns[i].Text);
        buffer.Append("\t");
     }

     buffer.Append("\n");

     for (int i = 0; i < lv.Items.Count; i++)
     {
        for (int j = 0; j < lv.Columns.Count; j++)
        {
            buffer.Append(lv.Items[i].SubItems[j].Text);
            buffer.Append("\t");
        }

        buffer.Append("\n");
    }

    Clipboard.SetText(buffer.ToString());
}

VB6

Public Sub CopyListViewToClipboard(lv As ListView)

    Dim buf As String
    Dim i As Integer
    Dim j As Integer

    For i = 1 To lv.ColumnHeaders.count

        buf = buf + lv.ColumnHeaders.Item(i).Text + vbTab

    Next


    buf = buf + vbCrLf

    For i = 1 To lv.ListItems.count

        buf = buf + lv.ListItems(i).Text

        For j = 1 To lv.ColumnHeaders.count - 1
            buf = buf + vbTab + lv.ListItems(i).SubItems(j)
        Next

        buf = buf + vbCrLf

    Next

    buf = buf + vbCrLf

    Clipboard.Clear
    Clipboard.SetText buf

End Sub

How to Fit all columns in a ListView in C#, VB.NET, and VB6

Code is shown below to Autofit the data in a listview for C#, VB.NET, and VB6:

C#

public void AutoFitListView(ListView lv)
{
   for (int i = 0; i <= lv.Columns.Count - 1; i++)     {          lv.Columns[i].Width = -2; // longest col head and item                                    // -1 for just longest item     } } 

VB.NET

Public Sub AutoFitListView(ByRef lv As ListView)

For i As Integer = 0 To lv.Columns.Count - 1

 lv.Columns(i).Width = -2

Next

End Sub

VB6
Unfortunately, the VB6 solution is a bit more complicated:

Private Const LVM_FIRST As Long = &H1000
Private Const LVM_SETCOLUMNWIDTH As Long = (LVM_FIRST + 30)
Private Const LVSCW_AUTOSIZE As Long = -1
Private Const LVSCW_AUTOSIZE_USEHEADER As Long = -2

Private Declare Function SendMessage Lib "user32" _
Alias "SendMessageA" _ (ByVal hwnd As Long, ByVal wMsg As Long, _ ByVal wParam As Long, lParam As Any) As Long

Public Sub AutoFitListView(lv As ListView)
   Dim i As Long

   For i = 0 To lv.ColumnHeaders.count - 1

        Call SendMessage(lv.hwnd, LVM_SETCOLUMNWIDTH, i, ByVal LVSCW_AUTOSIZE_USEHEADER)

   Next

End Sub

You can change the LVSCW_AUTOSIZE_USEHEADER to LVSCW_AUTOSIZE if you do not want to consider the Header when adjusting the size.

More examples of the VB6 approach can be found at:

http://vbnet.mvps.org/index.html?code/comctl/lvcolumnautosize.htm