Ex005, ComboBox
ComboBox is similar to ListBox except that ComboBox has Edit box, so that you can
enter new item from keyboard or select already existing items by selecting from drop-down
list.
Exercise 005: ComboBox
1. Drop two ComboBox, clear their text property, name first one 'cbFontName' and
the other 'cbFontSize'.
2. Drop a label, name it 'laFontTest', write 'Font test' on it's Caption.
3. Drop a button, and write '&Color' on it's Caption.
4. Drop a ColorDialg.
5. Write this code on form's OnCreate event (Don't forget to delete OnCreate begin keyword
befor pasting this code):
var
Counter: Byte;
begin
cbFontName.Items:= Screen.Fonts;
for Counter:= 4 to 32 do
cbFontSize.Items.Add(IntToStr(Counter*2));
6. Write this code on cbFontSize combo box's OnClick event:
laFontTest.Font.Size:=
StrToInt(cbFontSize.Text);
7. Write this code on cbFontName combo box's OnClick event:
laFontTest.Font.Name:= cbFontName.Text;
8. Write this code on Button's OnClick event:
if ColorDialog1.Execute then
laFontTest.Font.Color:=
ColorDialog1.Color;
9. Run the program and test it by selecting different font name, size, and color
using combo boxes and color button.
Notes:
- ComboBox has a Text property which represents user entry same like TEditBox, or
item selected from drop-down list.
- Screen is a global object which encapsulate some of user interface properties
and methods. Screen.Fonts is a TStringList in which all system fonts are listed.
- Assigning two StringLists copies all list items from a list to another such as:
cbFontName.Items:= Screen.Fonts;