I have known about Raize Components for a long time. The buzz I've always heard was something like this...
"Oh yeah, Raize is good if you want a nice consistent look to all of your components within your program."
That's not really very exciting when you are thinking about spending $400.
Then I watched a video from Code Rage 5 where Ray demonstrates and talks about his components. Wow, did this change my mind. I purchased Raize Components 6.0 three days later. Here is the Code Rage 5 video I'm talking about
UI Design with Raize Components.
There's also an XE2 Code Rage 6 video
UI Design with Raize Components and RAD Studio XE2
You owe it to yourself to watch one or both of these videos.
Anyway, I have a passion for using Id/Value pairs in all of my lookup code. I find it much easier to pass around an integer Id instead of the actual string value. I guess this comes from years of creating databases with lookup tables based on nonsensical auto-increment Id's. For example:
tblColors
| Id | Value |
| 1 | Blue |
| 2 | Green |
| 3 | Red |
| 4 | Yellow |
So, I was very excited when I learned that the TRzComboBox component from Raize supports Id/Value Pairs. You just right click on the control, choose Edit Items & Values and enter your Id value pairs.
When you want to retrieve the Value associated with the ItemIndex of the control you simply reference the
TRzComboBox.Value property.
Okay that was the easy part. Now how do you go about doing the opposite, setting the control so the ItemIndex refletcs the Id value? That's a good question.
Suppose we have the value 7 which represents "Seven" stored in an interger variable and we want to set the control so that Seven is the highlighted item.
You simply iterate through the control testing each of the values to see if it matches. Upon a match you set the ItemIndex.
Raize makes this easy beacause it exposes both the Value property and the Values property. Value corresponds to the ItemIndex and Values is a TStringList of all the values.
Below is a simple little program to demonstrate how to do set the ItemIndex to the Value. It does require Raize Componets 6.0 from
http://www.raize.com/
The key is a little helper procedure that accepts two parameters. The first is a TRzComboBox, and the second is the Id value. By passing the TRzComboBox by reference it allows any changes to the ItemIndex to happen directly to the control itself.
Procedure SetComboBoxValue(var cb:TRzComboBox; x:integer);
var i :integer;
begin
for i := 0 to cb.Count - 1 do
if x = StrToInt(cb.Values[i]) then
begin
cb.ItemIndex := i;
Exit;
end;
end;
As you can see, it simply iterates through the list of values looking for a match and when found it Exits.
Enjoy,
Semper Fi - Gunny Mike
UPDATE 08/08/2012 9:25 PM EST
I just received an email from Ray Konopka regarding
TRzComboBox.Value property. It turns out that the
Value property is a
read/write property. That means you can assign a value to the
Value property and it will change the
ItemIndex property automatically! How simple is that...
RzComboBox1.Value := IntToStr(7);
Thanks Ray and keep up the great work.
object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 203
ClientWidth = 226
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
PixelsPerInch = 96
TextHeight = 13
object RzButton1: TRzButton
Left = 64
Top = 112
Width = 110
Caption = 'Value = 1'
TabOrder = 0
OnClick = RzButton1Click
end
object RzComboBox1: TRzComboBox
Left = 64
Top = 32
Width = 110
Height = 21
TabOrder = 1
Text = 'One'
OnChange = RzComboBox1Change
Items.Strings = (
'One'
'Two'
'Three'
'Four'
'Five'
'Six'
'Seven'
'One Hundred'
'Nine Nine Nine')
ItemIndex = 0
Values.Strings = (
'1'
'2'
'3'
'4'
'5'
'6'
'7'
'100'
'999')
end
end
unit SetComboBox;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls,
Forms, Dialogs, StdCtrls, RzCmboBx, RzButton;
type
TForm1 = class(TForm)
RzButton1: TRzButton;
RzComboBox1: TRzComboBox;
procedure RzButton1Click(Sender: TObject);
procedure RzComboBox1Change(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
Procedure SetComboBoxValue(var cb:TRzComboBox; x:integer);
var
Form1: TForm1;
implementation
{$R *.dfm}
Procedure SetComboBoxValue(var cb:TRzComboBox; x:integer);
var i :integer;
begin
for i := 0 to cb.Count - 1 do
if x = StrToInt(cb.Values[i]) then
begin
cb.ItemIndex := i;
Exit;
end;
end;
procedure TForm1.RzButton1Click(Sender: TObject);
var
i,j : integer;
begin
i := Random(RzComboBox1.Count);
j := StrToInt(RzComboBox1.Values[i]);
RzButton1.Caption := 'Value = ' + IntToStr(j);
SetComboBoxValue(RzComboBox1,j);
end;
procedure TForm1.RzComboBox1Change(Sender: TObject);
begin
RzButton1.Caption := 'Value = ' + RzComboBox1.Value;
end;
end.
