Unreachable handles, unable to delete panel

Ihave a code something like it:

   function [Constraints]=screensec()

if nargin >=2
    ParentPanel=varargin{1};
else
    ParentPanel=figure('Position', [200 300 600 300],...
        'Toolbar','none','menubar','none');
end

%create array of level to ease the selection if unavailable later
LevelAr=['None';strcat(repmat({'Level_'},1,9)',cellstr(int2str([1:9]')))];
ConMod=[];

%Data for the first table
DesTitles= fieldnames(Output.Des);
SiDes= size(DesTitles,1);
DataDes=[DesTitles, repmat({'None'},SiDes,1)]

%Define number of nodes that can be selected
NbofNodes=1;

MainTable= uitable ('parent',ParentPanel,...
    'units','normalized',...
    'Position',[0 .7 .45 .3],'rowname',[],...  
    'columnname',{'Type' 'Stage'},...
    'columnformat',{'char' {'None' 'Level_1'}},...
    'columneditable', [false true true],'data', {'a';'b';'c'},...
    'celleditcallback',@Add_Level);

      function Add_Level(gcf,~,~)

          %Check levels change, remove useless level (not in order)
          Table=get(gcf,'data');         
          LevelNb= Table(:,2);        
          InClean=find(ismember(LevelAr(2:end),LevelNb)==0);     
          Level=InClean(1,1)-1;
          [~,IndToCh]=ismember(LevelNb,LevelAr(2:end));
          TableChange=(IndToCh>Level) %the +1 is to remove the 'None'
          Table(TableChange,2)={'None'};
          NewChoice=LevelAr(1:Level+2); %Create the new possibilities.
          set(gcf,'data',Table,'columnformat',{'char' NewChoice'});

          %Width of level panel 
          xsiz=0.33
          try
          delete(ConMod.ParentP(:))
          ConMod=[];
          end
          %Reinitialize        

          if Level>0
              for i=1:Level

                  ConMod.ParentP(i)=uipanel('units','normalized','parent', ParentPanel,...
                      'Position', [0+xsiz*(i-1) 0 xsiz .7],...
                      'title',['Level_',int2str(i)]);

                  ConMod.But.Min(i)=uicontrol('Parent', ConMod.ParentP(i),'units','normalized',...
                      'position',[.4 .9 .2 .1],'style','pushbutton',...
                      'string','All','callback',@All_Same);

                  ConMod.Level(i)= uitable('Parent', ConMod.ParentP(i),'units','normalized',...
                      'position', [0 0 1 .8],'rowname',[],...
                      'columneditable',[false true true true true],...
                      'columnname', {'Type' 'Min' 'Max' 'Min pos' 'Maxpos'});                

              end
          end

      end 
end

My problem is that every time I call the function, I am able to set('ConMod.But.Min(i)','string',xxx), but I am unable to delete ConMod.ParentP(i) directly, "it does not exist". where does the handle goes when parent are defined?

Basically I just want to create panel (kind of boxes) that will handle different controls and be able to supress them every time to reinitilise and create new ones (overwrite).

Is there a best practice tutorial for dynamic gui like this?

Thank you in advance

[Jan]

The posted function "function [Constraints]=screensec()" does not accept inputs. Therefore "if nargin >=2" cannot be true.

In "function Add_Level(gcf,~,~)" you redefine "gcf" as a local variable, such that the built-in function with the same name is not reachable anymore. This is not an error, but the effects may be surprising.

When you run "for i=1:Level", the loop is not entered for Level<1, so you can omit the check "if Level > 0".

Answer 1

[Jan]

You've posted just some parts of the code, you call it "something like this". But the cause of the error is concealed in the real code, while the posted one cannot run at all. Therefore we cannot guess, what's exactly going on.

Matt Figs 41 GUI examples are without doubt a good manual for dynamic GUIs.

[Johan]

I posted the code that now works. I added a global variable, it is now easier to delete and empty. I guess the handles was stuck in the figure... for me it looks a bit dirty, but I do not think I leave anything behind or anything accumulating...

Thank you for your answer at least!

[Jan]

I do not see global variables in your code. I usually store handles in a struct, and this struct in the figure using GUIDATA or SETAPPDATA.

[Johan]

ConMod=[];

I think it acts as a global variable in nested function as it appears in light blue (and works). It allows me to avoid playing with setappdata with which I am still feeling incomfortable.

Thank you,