topic Re: Listbox & reading multiple selections.. in .NET Forum

Listbox & reading multiple selections..

Anonymous — Thu, 02 Jun 2011 19:52:37 GMT

I'm sure the answer to this has been staring me in the face for the last few hours, but I haven't been able to see the solution (and searches haven't given me anything).

I have a listbox with multiselect (simple) enabled.

How can I "see" the text of the values the users selects (if there is more than 1)..

vb.net if you can.

TIA

Re: Listbox & reading multiple selections..

Anonymous — Thu, 02 Jun 2011 21:02:16 GMT

Here is a simple way if you just want the text

        For Each itm In ListBox1.SelectedItems
            MsgBox(itm)
        Next

Re: Listbox & reading multiple selections..

Anonymous — Thu, 02 Jun 2011 21:14:28 GMT

That was one of the first things I tried. Unfortunately it just returns an error..

However I just figured out that because I am using a dataset in the listbox, I have to dig a few more layers into it to get what I need.

Thank you for the kick 🙂

Re: Listbox & reading multiple selections..

Anonymous — Thu, 02 Jun 2011 21:32:50 GMT

These are empty but you can try

    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        For i As Integer = 0 To 10
            Dim ds As New DataSet
            ds.DataSetName = "Dataset" & i
            ListBox1.Items.Add(ds)
        Next
    End Sub

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        For Each itm In ListBox1.SelectedItems

            If TypeOf itm Is DataSet Then
                Dim ds As DataSet = itm
                MsgBox(ds.DataSetName)
            End If

        Next

    End Sub

Re: Listbox & reading multiple selections..

Hallex — Sat, 04 Jun 2011 11:44:34 GMT

Can you show the code how you've do fill a list box with data?

~'J'~

Re: Listbox & reading multiple selections..

Anonymous — Mon, 06 Jun 2011 07:15:23 GMT

Hello there

Maybe this wil help

ListItem Item;
foreach (int Item in ListBox.Items) {
if (Item.Selected == true) {
ItemText.Text += Item.Text + " ";
ItemValue.Text += Item.Value + " ";
}
}

Vb.Net

Dim Item As ListItem
For Each Item in ListBox.Items
    If Item.Selected = True Then
      ItemText.Text &= Item.Text & " "
      ItemValue.Text &= Item.Value & " "
    End If
Next

Kind regards,

Irvin

Re: Listbox & reading multiple selections..

Hallex — Mon, 06 Jun 2011 21:08:25 GMT

The question is about listbox when its items was pulled from dataset

if I understand this right

Perhaps, like this

-------------- in form declaration --------
Private System.Data.DataTable dtable;
.............


--------------on form Load event-----------

this.listBox1.Items.Clear();
this.listBox1.SelectionMode = SelectionMode.MultiSimple;
System.Data.DataSet dset = GetDataSetFromReader("C:\\Test\\blabla.txt", "Table");
dtable = dset.Tables["Table"];

this.listBox1.DisplayMember = dtable.Columns[0].ColumnName;
this.listBox1.ValueMember = dtable.Columns[0].ColumnName;
this.listBox1.DataSource = dtable;



--------------on button click event-----------
Private Sub Button1_Click(sender As Object, e As EventArgs)
	'just for debug only:
	'foreach  (DataRowView a in this.listBox1.SelectedItems)
	'     MessageBox.Show("Selected Listbox item: " + a.DataView.ToString());
	' fill list of string to store selected items
	Dim texts As New List(Of String)()
	Dim indices As ListBox.SelectedIndexCollection = Me.listBox1.SelectedIndices
	For Each i As Integer In indices
			'<-- get texts from 1st datatable column
		texts.Add(Me.dtable.Rows(i).ItemArray(0).ToString())
	Next
         'you can clear textboxes here before
	For Each ctl As Control In Me.Controls
		If TypeOf ctl Is TextBox Then
			Dim tb As TextBox = DirectCast(ctl, TextBox)
			Try
				' say you have 4 textboxes:
				If tb.Name = "textBox1" Then
					tb.Text = texts(0)
				End If
				If tb.Name = "textBox2" Then
					tb.Text = texts(1)
				End If
				If tb.Name = "textBox3" Then
					tb.Text = texts(2)
				End If
				If tb.Name = "textBox4" Then
					tb.Text = texts(3)
				End If
			Catch
				'empty catch block to bypass  if less then 4 items selected
			End Try
		End If
	Next

End Sub

----------------------create dataset from text file---------------------

Private Function GetDataSetFromReader(filename As String, usertable As String) As System.Data.DataSet
	Dim ds As New System.Data.DataSet()
	Dim filedir As String = (New System.IO.FileInfo(filename)).DirectoryName
	Dim srtconn As String = String.Format("Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source={0};" + "Extended Properties=""text;"";", filedir)
	Using conn As New OleDbConnection(srtconn)
		Try
			conn.Open()
			Dim da As New OleDbDataAdapter()

			Dim db As New OleDbCommandBuilder(da)
			Dim cmd As New OleDbCommand(String.Format("SELECT * FROM {0}", filename))
			cmd.Connection = conn
			da.SelectCommand = cmd
			Dim dataReader As OleDbDataReader = da.SelectCommand.ExecuteReader()
			Dim dt As New System.Data.DataTable()
			dt.TableName = usertable
			dt.Load(dataReader)
			ds.Tables.Add(dt)
			dataReader.Close()

			ds.AcceptChanges()
		Catch oex As OleDbException
			MessageBox.Show(oex.Message + vbLf + oex.StackTrace)
		Finally
			conn.Close()
		End Try
	End Using
	Return ds
End Function