[SOLVED] TCButton Array "Down" Property Not Working

[pixelink]

Okay... I have and example project.

I was originally using TSpeedButton to dynamically create a button array.However, there was no Hover Font Color.
LAINZ suggested using the TCButton, I love it! So customize-able!

However, the SpeedButton had the "Active" state that just automatically worked.
BUT, TCButton doesn't have that. The only property close to that is the "DOWN" state

And I can trigger that when the button is click. That works
However, if you click on multiple buttons they "go down" but previous ones that I click don't go back up.

So, the only way I know in theory is to loop through all the dynamically created buttons and set DOWN:=FALSE to clear everything.
And then only one button appears down.

Got it so far?

THE PROBLEM....

When i loop through the array to try an set all the buttons DOWN property to FALSE
I get errors saying the identifier is not known (or similar)

And what I don't understand is that

Item.Caption:='Button' + IntToStr(i); - works fine - "Caption" is exposed to the array

BUT

Item.Down:=false;  DOESN'T WORK. - Error: identifier idents no member "Down"

Why?

CODE JUST FOR TRYING TO RESET DOWN PROPERTY

Code: Pascal  [Select][+][-]

1.  
2. procedure TForm1.Button2Click(Sender: TObject);
3.  
4. // LOOP THROUGH BUTTONS - CHANGE DOWN TO FALSE
5.  
6.   var
7.   i: Integer;
8.   Item: TControl;
9. begin
10.   for i := (Panel1.ControlCount - 1) downto 0 do
11.   begin
12.     Item := Panel1.controls[i];
13.     Item.Caption:='Button' + IntToStr(i);
14.     Item.Down:=false;  - //DON'T WORK
15.     //TBCButton.Down:=false; - DON'T WORK
16.     //TBCButton(i).Down:=false; - DON'T WORK
17.  
18.   end;
19.  
20. end;
21.  
22.  

All other code works.
BUT if you want a project to see and try for yourself

Download from here:
https://www.pixelink.media/downloads/BtnArrays.zip

Thanks in advance

[pixelink]

Here is a screen shot of what i don't want to happen.

ONLY 1 button should be pressed down.

[pixelink]

What I don't get is that "Caption" is exposed as a Property, while "Down" is not in the code intellisense drop-down.

YET... "DOWN" is a property in the object inspector.

So, how do I get around something that is missing, or I am I even going to able to.

see screenshot

[pixelink]

Just so everyone knows.

Using TCButton1.Down:=False - directly works perfectly fine if you drag the control unto a form.
The property "DOWN" is there.

But, since I created the buttons dynamically, the "Item" (in my array loop) is not including the the "DOWN" property an an identifier.

I know the differences going on here.

[Josh]

Hi

The Down property is for the TBCButton.
TControl does not have this property.

You can access the property like

(item as TBCButton).Down:=

so a quick change of your code may help; I have not tested though so may contain bug(s)

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button2Click(Sender: TObject);
2.  
3. // LOOP THROUGH BUTTONS - CHANGE DOWN TO FALSE
4.  
5.   var
6.   i: Integer;
7.   Item: TControl;
8. begin
9.   for i := (Panel1.ControlCount - 1) downto 0 do
10.   begin
11.     Item := Panel1.controls[i];
12.     If Item is TBCButton then  // Added check in case panel has other controls
13.     Begin
14.        (item as TBCButton).Caption:='Button' + IntToStr(i);
15.        (item as TBCButton).Down:=false;  - //DON'T WORK
16.        //TBCButton.Down:=false; - DON'T WORK
17.        //TBCButton(i).Down:=false; - DON'T WORK
18.     end;
19.   end;
20. end;
21.  

Not you could use a with cause instead, my personal preference is casting as above that way I know exactly what is happening
ie
with (item as tbcbutton) do
begin
  down:=false;
  caption:='blah
.....
end;

[pixelink]

Hi

The Down property is for the TBCButton.
TControl does not have this property.

You can access the property like

(item as TBCButton).Down:=

so a quick change of your code may help; I have not tested though so may contain bug(s)

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button2Click(Sender: TObject);
2.  
3. // LOOP THROUGH BUTTONS - CHANGE DOWN TO FALSE
4.  
5.   var
6.   i: Integer;
7.   Item: TControl;
8. begin
9.   for i := (Panel1.ControlCount - 1) downto 0 do
10.   begin
11.     Item := Panel1.controls[i];
12.     If Item is TBCButton then  // Added check in case panel has other controls
13.     Begin
14.        (item as TBCButton).Caption:='Button' + IntToStr(i);
15.        (item as TBCButton).Down:=false;  - //DON'T WORK
16.        //TBCButton.Down:=false; - DON'T WORK
17.        //TBCButton(i).Down:=false; - DON'T WORK
18.     end;
19.   end;
20. end;
21.  

Well, that is weird, Drag a TCButton unto a form. It most certainly has a "DOWN" property... it works for me.

[Josh]

TControl is the base control,
TBCButton is a customized control that has additional properties like down, Hover, Gradients, etc etc etc, these are not part of the base TCOntrol.

[pixelink]

Hi

The Down property is for the TBCButton.
TControl does not have this property.

You can access the property like

(item as TBCButton).Down:=

so a quick change of your code may help; I have not tested though so may contain bug(s)

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button2Click(Sender: TObject);
2.  
3. // LOOP THROUGH BUTTONS - CHANGE DOWN TO FALSE
4.  
5.   var
6.   i: Integer;
7.   Item: TControl;
8. begin
9.   for i := (Panel1.ControlCount - 1) downto 0 do
10.   begin
11.     Item := Panel1.controls[i];
12.     If Item is TBCButton then  // Added check in case panel has other controls
13.     Begin
14.        (item as TBCButton).Caption:='Button' + IntToStr(i);
15.        (item as TBCButton).Down:=false;  - //DON'T WORK
16.        //TBCButton.Down:=false; - DON'T WORK
17.        //TBCButton(i).Down:=false; - DON'T WORK
18.     end;
19.   end;
20. end;
21.  

Not you could use a with cause instead, my personal preference is casting as above that way I know exactly what is happening
ie
with (item as tbcbutton) do
begin
  down:=false;
  caption:='blah
.....
end;

PERFECT - IT WORKS!

Code: Pascal  [Select][+][-]

1.  
2. (item as TBCButton).Down:=false;
3.  
4.  

Hmmm, I tried a lot of ways, but never would of thought that!


THANK YOU!

[pixelink]

TControl is the base control,
TBCButton is a customized control that has additional properties like down, Hover, Gradients, etc etc etc, these are not part of the base TCOntrol.

Oh, make sense.

[howardpc]

In fact, you only need the check "if item is TBCButton" once.
You don't need the "as" checks as well.

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button2Click(Sender: TObject);var
2.   i: Integer;
3.   item: TControl;
4. begin
5.   for i := (Panel1.ControlCount - 1) downto 0 do
6.   begin
7.     item := Panel1.controls[i];
8.     if item is TBCButton then
9.       begin
10.         item.Caption:='Button' + IntToStr(i);
11.         TBCButton(item).Down := False;
12.       end;
13.   end;
14. end;

[lucamar]

In fact, you only need the check "if item is TBCButton" once.
You don't need the "as" checks as well.

The "Something as TSomeClas" is not a check, it is the elegant  (and safer) way of casting Someting as a TSomeClass instead of using the not-always-safe hard-cast TSomeClass(Something).

There are not many differences but the main one is that using as allows the compiler (and runtime?) to check whether it's safe to cast, while the hardcast forces it to cast whether it's safe or not.

ETA Forgot to say that if you really know what you're doing (as in this case, after the check with "is") the hard-cast may be be slightly quicker. Avoiding all those pesky checks and all that.

So you're mostly right

[howardpc]

Perhaps I was foolish to term the "as" operator a "check".
It is only a check in the sense that if the potential cast is invalid it will raise an exception, which is rarely what the user wants to encounter.

If a cast is unsafe it means the programmer is at fault, not the user, and so some uses of "as" I see are simply lazy programming by people who perhaps aren't really sure what they are doing, and throw in an "as" to "protect" flawed code.

IMHO it is far better to make an explicit check using "is" which returns a clear boolean result. Provided the result is True, an appropriate hard cast is perfectly valid, and all risk of an exception (at least an exception on account of an invalid cast) is removed.