Alias value for Combobox items

[golcarlad]

Is there a way for a combobox item to have an "alias" value e.g. if you select from colours combobox - RED, then you can return a value of 987, or BLUE would return 876 - whatever.
Bearing in mind you cant use Tag property when pre-popping a combobox at design time.
Or is this a case for custom controls?

 

[JurkMonkey]

ComboBoxes are a bit dumb.

Create a hashtable that uses the combobox index as key, and your "alias" as the value. Just remember to clear this hash table whenever you clear your combobox

 

[Aptitude]

VB6 used to include a property called ItemData for doing this. A while ago I wrote an article about how to emulate this behaviour in VB.Net. The same technique should be possible in C#.

The article is here: [URL unfurl="true"]http://www.mgbrown.com/PermaLink37.aspx[/url]

 

[Aptitude]

Looks like Tek-Tips messed the link up. It should be:

http://www.mgbrown.com/PermaLi-nk37.aspx

but without the hyphen. Why oh why are they replacing link37 with that dum rubbish?

 

[golcarlad]

Cheers guys - its nice to know that comboboxes are dumb afterall, I always kept trying to make them do stuff, I they just dont want to play! lol

 

[dEVooXiAm]

ComboBoxes are not dumb.. and you dont need any hash tables to have more data on them.

As you might have already noticed, ComboBox.Items.Add requires an object variable, NOT just a string. This means you can add actual objects to the list, whose structure is up to you. Just dont forget to set ComboBox.DisplayMember and ComboBox.ValueMember (if needed) to the names of corresponding object's properties.

Example:

class MyOwnListItem
{
   private string text;
   private int value;

   public string Text { get { return text; } }
   public int Value { get { return value; } }

   public MyOwnListItem(string newText, int newValue)
   {
      text = newText;
      value = newValue;
   }
}

class MyForm
{
   // .........
   protected void FillComboBox()
   {
       myCombo.DisplayMember = "Text";
       myCombo.ValueMember = "Value";
       myCombo.Items.Add(new MyOwnListItem("One", 1));
       myCombo.Items.Add(new MyOwnListItem("Two", 2));
   }

   protected void AccessComboBox()
   {
      string selText = myCombo.SelectedText;
      int selValue = (int) myCombo.SelectedValue;
      MyOwnListItem selItem = (MyOwnListItem) myCombo.SelectedItem;
   }
}

good luck

------------------
When you do it, do it right.