[SOLVED] Virtual TreeView add/delete columns at runtime

[JD]

Hi there everyone,

I have a virtual treeview that I use as a grid and I want to add columns to it dynamically. The data structure is just a dynamic array of string and it is working very well for this purpose. This means that I can increase or decrease the columns in the virtual treeview at will.

The code snippet for column creation and deletion is shown below:

Code: Pascal  [Select][+][-]

1.       //
2.       if ACreateColumns then
3.       begin
4.         ATree.BeginUpdate;
5.        
6.         //intOldColumns := ATree.Header.Columns.Count;
7.         //// Delete the existing columns
8.         //for intGridCol := 0 to Pred(intOldColumns) do
9.         //  ATree.Header.Columns.Delete(intGridCol);
10.  
11.         ATree.Header.Columns.Clear;
12.         //
13.         for intGridCol := 0 to Pred(intColMax) do
14.         begin
15.           ATree.Header.Columns.Add;
16.           ATree.Header.Columns[intGridCol].Width := 120;
17.           // Column titles - from a JSON array
18.           ATree.Header.Columns[intGridCol].Text := UpCase(StringReplace(jsArrayRow.Objects[0].Names[intGridCol], '_', ' ', [rfReplaceAll]))
19.         end;
20.        
21.         //
22.         ATree.Header.Options := ATree.Header.Options + [{hoAutoResize,} hoVisible];
23.         ATree.Header.Height   := 26;
24.         //
25.         ATree.Invalidate;
26.         ATree.EndUpdate;
27.       end;
28.  

The code above works but the only problem is if I fill the virtual treeview with many columns, then clear it and fill the virtual treeview with fewer columns than before, I can still see the columns I had deleted earlier. It is as if the virtual treeview does not repaint/refresh itself properly.

Can anyone help me figure out what is wrong?

Cheers,

JD

[taazz]

have you tried to call invalidate after the endupdate?

[JD]

Hi there taazz,

I tried it but it still yields the same result. See screenshots

JD

[marcov]

Set the position field?

Anyway, here is my runtime instantiation, which is basically an evolved version of the grid in the "advanced" demo:

Code: Pascal  [Select][+][-]

1.   b:=objtype.create; // self descriptive class for vsteditor module, based on TXMLConfig nodes.
2.   for i:=0 to length(b.fielddescr)-1 do
3.     begin
4.       col:=actievst.header.Columns.Add;
5.       col.Style:=vsOwnerDraw;
6.       col.Options:=col.Options;
7.       if invisible in b.fielddescr[i].properties then
8.         col.Options:=col.Options-[covisible];
9.       if b.fielddescr[i].fieldtype=vtboolean then
10.        col.margin:=10
11.       else
12.        col.margin:=0;
13.       if b.fielddescr[i].color=tcolor(0) then
14.         col.Color:=globalcolor // colortest[i mod (high(colortest)+1)];
15.       else
16.         col.Color:=b.fielddescr[i].color;
17.       col.position:=i+1;
18.       col.width:=b.fielddescr[i].ColWidth;
19.       col.Text := b.fielddescr[i].description;
20.     end;
21.   b.free;
22.   ActieVST.Align:=alclient;
23.   actievst.RootNodeCount:=numberitems;
24.  
25.   actievst.Invalidate;
26.   actievst.Visible:=true;

[JD]

Hi there marcov,

Thanks for the reply. It still does not work. 

Your code is very similar to mine

Code: [Select]

for each field description
   add a column
   set the column's properties
   set the column header text
invalidate

The problem must be with the way older columns are removed.

I've tried ATree.Header.Columns.Clear and ATree.Clear and then called ATree.Invalidate but it is not working as expected. I still get the same visual results in the attachments I sent earlier.

JD

[balazsszekely]

It works fine here. Which version do you use? Please test attached project.

PS: If you still have issues upload a small demo.

[JD]

My sincere apologies to everyone. I found the problem. I ran the program on my Linux Mint 18.3 laptop and there were no drawing problems at all. It was just as I wanted it.

I then went back to my Windows laptop. I use Windows 7 but I added a theme to make it look like Windows 10 

Once I reverted to native Windows 7 theme and controls on the laptop, everything was perfect. No black headers, no drawing problems, everything was fine. I have egg on my face.

Thanks to everyone that offered suggestions and/or code.

JD