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DevExpress Bars 5 to 6 - BarByName is gone, BarByComponentName not functioning properly. Help?

Posted on 2011-03-18
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Last Modified: 2012-05-11
I use the method to introduce new elements to the bar during run time, when I say BarByComponent name, I mean that I need to invoke the name of the bar into a variable so I can call it whenever I want it, however I suspect this is not the case.

Issue: Instead of introducing the new element, a blank space is introduced instead, when clicked upon it generates an access violation error.

Example of my code:

var
  BarX: TdxBar;
begin
BarX := mainBar.BarByComponentName('barMenuList');
...

Thank you.
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Question by:John86a
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12 Comments
 
LVL 32

Expert Comment

by:Ephraim Wangoya
ID: 35169272

Your question is not very clear
However yo need to test the validity of the BarX
Assuming MainBar is type TdxBarManager

var
  BarX: TdxBar;
begin
  BarX := MainBar.BarByComponentName('barMenuList');
  if Assigned(BarX) then
  begin
      //do your stuff  
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Author Comment

by:John86a
ID: 35171533
I was using that correctly, but after studying mad except logins I found out the reason for the error..

exception class   : EAccessViolation
exception message : Access violation at address 0064BEA0 in module 'RF8.exe'. Read of address 000000A0.

Main ($9c8):
0064bea0 +00000 RF8.exe      dxBar              32483   +0 TdxBar.GetItemLinks
006497b5 +00005 RF8.exe      dxBar              32483   +0 TdxBar.GetControl

At this exact point inside dxBar.pas:

function TdxBarItemControl.GetItem: TdxBarItem
begin
 Result := GetItemByLink(FItemLink)
end;
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LVL 24

Expert Comment

by:jimyX
ID: 35171574
Would you test following code please and show what's the result:
var
  BarX : TdxBar;
  Found : Boolean;
  i : integer;
begin
  Found := False;
  for i := 0 to MainBar.Bars.Count-1 do
    begin
      if MainBar.Bars[i].Name = 'barMenuList' then
        begin
          Found := True;
          //BarX := MainBar.Bars[i];
          break;
        end;
    end;

  if Found then
    Showmessage('barMenuList found')
  else
    Showmessage('barMenuList not found')
end;

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LVL 24

Assisted Solution

by:jimyX
jimyX earned 332 total points
ID: 35171608
Just noticed something, doesn't "BarX" require to be created first before used?
Something like this:
var
  BarX: TdxBar;
begin
  BarX := TdxBar.Create(MainBar);
  BarX := MainBar.BarByComponentName('barMenuList');
  //...
  BarX.Free;
end;

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Accepted Solution

by:
Ephraim Wangoya earned 668 total points
ID: 35171619
@jimmyX
What is that?
How can you create an object that you are searching for?
That is plain wrong.
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Author Comment

by:John86a
ID: 35171650
That's not the origin of the error, this is:

try
 dxbarManager.LockUpdate := true;
 DeleteMenus;
 RecreateMenus(mainBar);
 Finally
 try
 dxBarManager.LockUpdate := False;
 Except
 end;
end;
0
 
LVL 24

Expert Comment

by:jimyX
ID: 35171789
@ ewangoya
What to say man, over 12 hours looking at the screen, my brain is fried.
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LVL 32

Expert Comment

by:Ephraim Wangoya
ID: 35172859

@jimmyX
I know the feeling, happens to all of us one time or another
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LVL 32

Assisted Solution

by:Ephraim Wangoya
Ephraim Wangoya earned 668 total points
ID: 35173318

What is the code in DeleteMenus.
Before destroying an item in your DeleteMenus procedure, change its visible property to false Control.Visible := False

try
 dxbarManager.LockUpdate := true;
  try
    try
      DeleteMenus;
      RecreateMenus(mainBar);
    except
      //why are you hiding the exception
    end;
 Finally
   dxBarManager.LockUpdate := False;
 end;

  //try updating the mainBar
  mainBar.Update;  //or refresh
end;
0
 

Author Comment

by:John86a
ID: 35173613
Update or refresh does not exist. Do you have msn? I have separated its and bits of the parts where debugger accused the error. I do not wish to post it here.
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Author Comment

by:John86a
ID: 35173616
I'll accept your msn as a solution, and then we can go on from there.
0
 

Author Closing Comment

by:John86a
ID: 35180401
Issue unresolved, going to be doing some debugging to get to the bottom of it. Might post another question later.
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