How to change properties of a TlistBoxItem in a an

问题:

In my program, i made a function which reads a xml of a blog and put the Titles in a TListBox. But i need to change some properties in TListBoxItem, like font, height and color, but it doesn't change.

How to set it in runtime ?

repeat
  Title := ANode.ChildNodes['title'].Text;
  Link := ANode.ChildNodes['link'].Text;
  Desc := ANode.ChildNodes['description'].Text;
  DataPub := ANode.ChildNodes['pubDate'].Text;
  SetLength(Vet_News, Pos + 1);
  Vet_Nesw[Pos] := '<h2>'+Title+'</h2>'+Desc;
  Itemx := TListBoxItem.Create(self);
  Itemx.Text := Title;
  Itemx.ItemData.Detail := DataPub;
  Itemx.ItemData.accessory := TListBoxItemData.TAccessory.aMore;
  Itemx.TextSettings.WordWrap := true;
  Itemx.TextSettings.FontColor := TAlphaColorRec.Darkorange;
  Itemx.Height := 65;
  Itemx.FontColor := TAlphaColorRec.Darkorange; // i tried two ways to change the color
  lbNews.AddObject(Itemx); // lbnews is a Tlistbox 
  Inc(Pos);
  ANode := ANode.NextSibling;
until ANode = nil;

回答1:

[Tested with Delphi-XE7] At runtime, Listboxitems already have a calculated style stored in : aListboxItem.StyledSettings. To change a setting at runtime, you first have to remove it from the list of styled settings.

For example, if you want to change the FontColor, first remove the styled fontcolor:

aListboxItem.StyledSettings := aListboxItem.StyledSettings - [TStyledSetting.FontColor];

Then apply another one (let's say Green):

aListboxItem.FontColor := TAlphaColors.Green;

The TStyledSetting constants and corresponding TTextSettings properties are listed here in Delphi's doc.

Examples for changing styles at runtime can be found here and there.

Nota Bene: theListBox.Items[i] gives access to item content, not the item itself. To grab a ListboxItem as a control, and then act on its properties, you can use:

aListboxItem := theListBox.ListItems[i];

or

aListboxItem := theListBox.ItemByIndex(i);

Both giving exactly the same result, I cannot say if one is better.