Bug in DropDownList?
Victor Garcia Aprea
I'm not sure if this is the right place to post possible bugs, if not please
tell me where this should go.
By answering a question in the webcontrols newsgroups I found what I think
may be a bug.
I was trying to give a simple example on how to add an attribute to an
<option> element. But I didnt worked.
I tried:
[C#]
ListItem li = new ListItem("One","1");
li.Attributes.Add("style","background-color:red");
// dd1 is an instance of DropDownList class
dd1.Items.Add(li);
The ListItem class has an Attributes collection (I already know that style
object for the <option> element only accepts background-color and color and
ignores everything else) so I tought that when rendering its Items the
DropDownList class would also output the contents of this collection. But my
simple example was not working so I ended up dissasemblying the
RenderContents method of the DropDownList class and found that it output its
<option> elements with only a selected (based on the Selected property of
the ListItem) and a value attribute. There is no reference at all a the
Attributes collection of a ListItem.
I think this may be a bug and let MS know about it,
-Victor.
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Ken Cox [Microsoft MVP]
Can individual list items have styles in HTML? Wouldn't the style be applied
to the control as a whole?
If so, this works:
DropDownList1.BackColor = Color.Red
Ken
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Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Dim li As New ListItem()
li.Value = "1"
li.Text = "One"
DropDownList1.Items.Add(li)
DropDownList1.BackColor = Color.Red
End Sub
"Victor Garcia Aprea" <v...@NOobiesSPAM.com> wrote in message
news:#liY77uzBHA.2380@tkmsftngp04...
Victor Garcia Aprea
> Can individual list items have styles in HTML? Wouldn't the style be
applied
> to the control as a whole?
Yes they can. I checked the html reference at msdn. The <option> element
supports a sytle object which in turns accepts background-color and color
and ignores everything else. So writing something like this:
> DropDownList1.BackColor = Color.Red
This will not help in setting each item individually to a different color.
This is an example:
<select>
<option style="color:red" value="1">One</option>
<option style="color:blue" value="1">One</option>
</select>
This actually gives you a different color for each item (I tried it and it
worked ok).
But as I posted before the RenderContents of DropDownList is just ignoring
the Attributes collection of the ListItem class.
-Victor.
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"Ken Cox [Microsoft MVP]" <BANSPAM...@sympatico.ca> wrote in message
news:OVOV4XvzBHA.2508@tkmsftngp03...
Ken Cox [Microsoft MVP]
something every day.
I suspect you've got a bug there.
Ken
"Victor Garcia Aprea" <v...@NOobiesSPAM.com> wrote in message
news:OfanMcvzBHA.1512@tkmsftngp05...
Victor Garcia Aprea
While we wait to confirm if that is a bug, I have written a modified version
of RenderContents:
[C#]
override protected void RenderContents(HtmlTextWriter writer)
{
for(int c=0;c<Items.Count;c++)
{
ListItem i = Items[c];
writer.WriteBeginTag("option");
if(i.Selected)
writer.WriteAttribute("selected","selected",false);
writer.WriteAttribute("value",i.Value,true);
IEnumerator d = Items[c].Attributes.Keys.GetEnumerator();
while(d.MoveNext())
writer.WriteAttribute(d.Current.ToString(),Items[c].Attributes[d.Current.ToS
tring()]);
writer.Write('>');
System.Web.HttpUtility.HtmlEncode(i.Text,writer);
writer.WriteEndTag("option");
writer.WriteLine();
}
}
Deriving a new class from DropDownList and overriding its RenderContents
method with the method above will output the Attributes collection.
-Victor.
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"Ken Cox [Microsoft MVP]" <BANSPAM...@sympatico.ca> wrote in message
news:ea#VUpvzBHA.2640@tkmsftngp07...
Ken Cox [Microsoft MVP]
BUG: Attributes Property of ListItem Only Works Within an HtmlSelect Control
(Q309338)
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q309338
The ListItem control has a property Attributes of type AttributeCollection .
When the ListItem is inside a RadioButtonList or a DropDownList , key-value
pairs that you assign to the Attributes property of the ListItem (either
programmatically or declaratively) are not rendered.
Ken
"Victor Garcia Aprea" <v...@NOobiesSPAM.com> wrote in message
news:u4Yvw5wzBHA.2520@tkmsftngp05...
Victor Garcia Aprea
it applies exactly to the case we found yesterday.
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"Ken Cox [Microsoft MVP]" <BANSPAM...@sympatico.ca> wrote in message
news:e6Buai0zBHA.2272@tkmsftngp02...