C#

/* Assumes
TreeView treeView1. Parent node must have Tag "Parent" and
exactly two child nodes for drag to work
ListView listView1 with three columns already added.

Events subscribed
treeView1.ItemDrag += new ItemDragEventHandler(treeView1_ItemDrag);
listView1.DragOver += new DragEventHandler(listView1_DragOver);
listView1.DragDrop += new DragEventHandler(listView1_DragDrop);
*/
void treeView1_ItemDrag(object sender, ItemDragEventArgs e)
{
    TreeNode nodeData = (TreeNode)e.Item;
    // set as selected
    treeView1.SelectedNode = nodeData;
    // check is parent using tag property
    if ((string)nodeData.Tag == "Parent" && nodeData.Nodes.Count == 2)
        // OK
        treeView1.DoDragDrop(nodeData, DragDropEffects.Copy);
}
void listView1_DragOver(object sender, DragEventArgs e)
{
    // default to none
    e.Effect = DragDropEffects.None;
    // get tree node
    TreeNode nodeData = (TreeNode)e.Data.GetData(typeof(TreeNode));
    // check data in case coming from elsewhere
    if (nodeData != null && (string)nodeData.Tag == "Parent" && nodeData.Nodes.Count == 2)
        // OK so proceed
        e.Effect = DragDropEffects.Copy;

}
void listView1_DragDrop(object sender, DragEventArgs e)
{
    // get tree node
    TreeNode nodeData = (TreeNode)e.Data.GetData(typeof(TreeNode));
    // check data
    if (nodeData != null && (string)nodeData.Tag == "Parent" && nodeData.Nodes.Count == 2)
    {
        // convert
        ListViewItem newItem = new ListViewItem(nodeData.Text);
        foreach (TreeNode childNode in nodeData.Nodes)
        {
            ListViewItem.ListViewSubItem newSub = new ListViewItem.ListViewSubItem();
            newSub.Text = childNode.Text;
            // add children to parent
            newItem.SubItems.Add(newSub);
        }
        // add parent
        listView1.Items.Add(newItem);
    }
}

John Simmons / outlaw programmer wrote:

Personally, I wouldn't use a Timer object because it's the lowest priority message in Windows, and in a busy system, there's no guarantee the message will even be handled. Instead, I use a BackgroundWorker

John Simmons / outlaw programmer wrote:

all controls of the same type are grouped in the same place in intellisense.

protected void BtnUpdate_Click(object sender, EventArgs e)
{
    dt = (DataTable)Session["Cart"];
    CheckBox chkSelected = new CheckBox();

    foreach (DataGridItem dgItem in DataGrid2.Items)
    {
        chkSelected = (CheckBox)dgItem.FindControl("chkSelection");

        if (chkSelected.Checked == true)
        {

            TextBox TxtQTY = (TextBox)dgItem.Cells[2].FindControl("TxtQTY");
            int Txt2 = Convert.ToInt32(TxtQTY.Text);

            Label lblProduct_Id = (Label)dgItem.Cells[0].FindControl("lblProduct_Id");
            string id2 = lblProduct_Id.Text;

            Label lblDescription = (Label)dgItem.Cells[1].FindControl("lblDescription");
            string desc2 = lblDescription.Text;

            Label lblPrice = (Label)dgItem.Cells[3].FindControl("lblPrice");
            float price2 = Convert.ToSingle(lblPrice.Text);

            Label lblCost = (Label)dgItem.Cells[3].FindControl("lblCost");
            float cost2 = Convert.ToSingle(lblCost.Text);

            float final_cost = price2 * Txt2;

              DataRow myrow = dt.NewRow();
              myrow["REF"] = id2;
              myrow["Description"] = desc2;
              myrow["QTY"] = Txt2;
              myrow["Price"] = price2;
              myrow["Cost"] = final_cost;

              dt.Rows.Add(myrow);
              dt.AcceptChanges();
              Session["data"] = dt;
        }

    }
    //dt.Rows.RemoveAt(index);
    DataGrid2.DataSource = dt;
    DataGrid2.DataBind();
}