C#

using Microsoft.Office.Core;

private void ReadExcelValue()
{
    object o = System.Reflection.Missing.Value;
 
    Excel.Application objE = new Excel.Application();
    Excel.Workbooks objBooks = null;
    Excel.Workbook objB = null;
    Excel.Worksheet objS = null;
 
    objE.Workbooks.Open(Server.MapPath("spreadsheet.xls"), o, o, o, o, o, o, o, o, o, o, o, o, o, o);
    objBooks = objE.Workbooks;
    objB = objBooks[(object)1];
 
    objS = (Excel.Worksheet)objB.Worksheets[(object)1];
 
    //write out the text in cell "A1"
    Response.Write(((Excel.Range)objS.Cells[1, 1]).Text);
 
    Release(objS);
 
    if (objB != null)
        objB.Close(false, o, o);
    Release(objB);
 
    if (objBooks != null)
        objBooks.Close();
    Release(objBooks);
 
    if (objE != null)
        objE.Quit();
    Release(objE);
 
    GC.Collect();
 
    System.Diagnostics.Process[] objPr = System.Diagnostics.Process.GetProcessesByName("Excel");
    foreach (System.Diagnostics.Process pr in objPr)
        pr.Kill();
}

private void Release(object obj)
{
    try
    {
        System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
    }
    catch { }
    finally
    {
        obj = null;
    }
}

iakob wrote:

But how do I get the listboxitem that were clicked

private void listBox1_MouseDown(object sender, MouseEventArgs e)
{
   ListBox listBox = sender as ListBox;
 
   if (e.Button == MouseButtons.Right)
   {
      int index = listBox.IndexFromPoint(e.X, e.Y);
      if (index >= 0 && index < listBox.Items.Count)
      {
         listBox.SelectedIndex = index;
      }
      listBox.Refresh();
   }
}

private void deleteToolStripMenuItem_Click(object sender, EventArgs e)
{
   if (listBox1.SelectedItems.Count > 0)
   {
      MessageBox.Show(listBox1.SelectedItems[0].ToString());
   }
   else
   {
      MessageBox.Show("You didn't select an item!");
   }
}

this.rtbConsole.Text += NewText;

this.rtbConsole.AppendText(NewText);