Tooltip for each items in a combo box

Question

I just want to add a tooltip for each item in a combo box. i am using c#.net windows application.

There is no option like

combobox.items[1].tooltip();

Is there any way to add tooltip it ?

Answer 1

My solution:

ToolTip toolTip = new ToolTip() { AutoPopDelay = 0, InitialDelay = 0, ReshowDelay = 0, ShowAlways = true, };
comboBox.DrawMode = DrawMode.OwnerDrawFixed;
comboBox.DrawItem += (s, e) =>
{
    e.DrawBackground();
    string text = comboBox.GetItemText(comboBox.Items[e.Index]);
    using (SolidBrush br = new SolidBrush(e.ForeColor))
        e.Graphics.DrawString(text, e.Font, br, e.Bounds);
    if ((e.State & DrawItemState.Selected) == DrawItemState.Selected && comboBox.DroppedDown)
        toolTip.Show(text, comboBox, e.Bounds.Right, e.Bounds.Bottom + 4);
    e.DrawFocusRectangle();
};
comboBox.DropDownClosed += (s, e) =>
    toolTip.Hide(comboBox);

Answer 2

With WPF use a ComboBox.ItemTemplate

<ComboBox               
    ItemsSource="{Binding Path=ComboBoxItemViewModels}"
    SelectedValue="{Binding SelectedComboBoxItem, 
    SelectedValuePath="Name"                
>
  <ComboBox.ItemTemplate>
    <DataTemplate>
      <TextBlock Text="{Binding Path=Name}" ToolTip="{Binding Path=Description}"/>
    </DataTemplate>
  </ComboBox.ItemTemplate>
</ComboBox>

Answer 3

Building upon the solution from Michael Sorens (fixed a few bugs and added features). A few things this does:

• It will display a preview of a file associated with the drop down (in this case a book title from an XML file, or you can add more descriptions in the tooltip, or display something completely different).
• It does not display tooltip for the "0" positon in the drop down (I had a placeholder, but you can simply remove the e.index>0 in the second if statement).

• It does not display the tooltip when the dropdown is CLOSED.

  private void comboBox1_DrawItem(object sender, DrawItemEventArgs e)
  {
      ComboBox comboBox1 = (ComboBox)sender;
      if (e.Index >= 0)
      {//Draws all items in drop down menu
          String text = comboBox1.GetItemText(comboBox1.Items[e.Index]);
          e.DrawBackground();
          using (SolidBrush br = new SolidBrush(e.ForeColor))
          {
              e.Graphics.DrawString(text, e.Font, br, e.Bounds);
          }
  
          if ((e.State & DrawItemState.Selected) == DrawItemState.Selected && e.Index > 0 && comboBox1.DroppedDown)
          {//Only draws tooltip when item 1+ are highlighted.  I had a "--" placeholder in the 0 position
              try
              {
                  XmlDocument doc;
                  XmlNode testNode;
                  doc = new XmlDocument();
                  String testXMLDoc = String.Format(@"{0}\{1}.xml", filePath, fileName);//global variables
                  String toolTip = "---Preview of File---";
                  doc.Load(testXMLDoc);
                  testNode = doc.SelectSingleNode("/Books");
                  if (testNode.HasChildNodes)
                  {
                      XmlNodeList nodeList = testNode.SelectNodes("Book");
                      foreach (XmlNode xmlNode in nodeList)
                      {
                          toolTip += "\r\n" + xmlNode.SelectSingleNode("Title").InnerXml;
                      }
                  }
                  this.toolTipHelp.Show(toolTip, comboBox1, e.Bounds.Right, e.Bounds.Bottom);
              }
              catch (Exception tp)
              {
                  Debug.WriteLine("Error in comboBox1 tooltip: " + tp);
              }
          }
          else
          {
              this.toolTipHelp.Hide(comboBox1);
          }
      }
      else
      {
          this.toolTipHelp.Hide(comboBox1);
      }
      e.DrawFocusRectangle();
  }