HDPI TDBAdvGrid StringToColumnStates and ColumnStatesToString

VCL TMS VCL UI Pack
1

There appears to be a HDPI problem with saving/restoring column states for TDBAdvGrid when using them on a frame. Here is a screen shot showing the problem I am having. I have a main form which dynamically creates frames on tabsheets containing a TDBAdvGrid and allows you to close them afterwards. I save and restore the column widths in an ini file. The screen shot shows the values saved and retrieved from the ini file when I create the frame and destroy it. I have not changed anything other than loading the data. I'll investigate it further on my side as perhaps it's a problem loading the data rather than these two functions but that is where I am seeing the problem so I wanted to run it by you in case you have any insight that might help.

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2

What Delphi version do you use?
What is the DPI situation? DPI at time of saving? DPI at time of loading?

3

Delphi 11 Update 3 patch 1
Resolution is shown in the screenshot font scale 500% display resolution 7680 x 3240

4

I have updated my Delphi with the latest VCL UI pack 13.0.1.0

5

I suspect it is something I am doing wrong. I have a grid on a form that I am saving/restoring in a similar way and that works fine but I seem to remember their are issues with frames and HDPI. Please don't waste any time on it for now, I just thought it might have been a known issue with frames. I have to park this job for a bit anyway and it will be a week at least before I am back on it. Many thanks.

6

Ok, thanks for informing. Let us know if further investigation is needed.

7

Hi Bruno,
ColPersistDemo_2023-09-26.zip (26.9 KB)

Please find attached a demo application that shows the problem with frames and HDPI. I am running this on a Parallels VM. Display settings; Scale 500%, resolution 7680 x 3240. When I save/restore column states form a form it's fine but on a frame it multiplies it by 2 each time. Here is an extract from the log of the test app.

[26/09/2023 10:02:26][Value: Windows 11 (Version 22H2, OS Build 22621.2283, 64-bit Edition)][Type: string]
[26/09/2023 10:02:31][Trace][Value: ReadString( STATES,FORM ) = 10#40,128,128,128,128,128,128,128,128,128#0,1,9,2,3,4,5,6,7,8#1,0,1,1,1,1,1,1,1,1][Type: string][Type: string][Type: string]
[26/09/2023 10:02:37][Trace][Value: WriteString( STATES,FORM,10#40,128,128,128,128,128,128,128,128,128#0,1,9,2,3,4,5,6,7,8#1,0,1,1,1,1,1,1,1,1 )][Type: string][Type: string][Type: string]
[26/09/2023 10:02:40][Trace][Value: ReadString( STATES,FRAME ) = 10#40,128,128,128,128,128,128,128,128,128#0,1,9,2,3,4,5,6,7,8#1,0,1,1,1,1,1,1,1,1][Type: string][Type: string][Type: string]
[26/09/2023 10:02:42][Trace][Value: WriteString( STATES,FRAME,10#80,256,256,256,256,256,256,256,256,128#0,1,9,2,3,4,5,6,7,8#1,0,1,1,1,1,1,1,1,1 )][Type: string][Type: string][Type: string]
8

We have seen this issue. Sadly it seems tied to an underlying VCL problem.
(We expect you will see the same problem with getting and setting the column widths of a TStringGrid when used on a frame).
It is due to a different sequence of creating the frame and calling ChangeScale in this create process. We have not yet found a reliable workaround.
This might also change in a future Delphi version, so at this point, it is unsure what to do about this issue.

9

Thanks Bruno, that's helpful. After what you said I overridded the ScaleForPPI procedure and put the code to restore the column states in there and it appears to work. I only have one monitor now, so can't test what happens if you drag it on to another screen but I suspect it will just reset to what's saved in the ini file which again wouldn't be a problem. What do you think to this approach, do you think it is a reasonable workaround?

procedure TFrameDemo.RestoreColumnStates;
var
  inif: TINIFile;
  colstates: string;
  i: Integer;
  col: TDBGridColumnItem;
begin
  for i := 0 to ADOTable1.FieldCount - 1 do
  begin
    CheckListBox1.Items.Add( ADOTable1.Fields[ i ].FieldName );
    CheckListBox1.Checked[ i ] := true;
  end;

  DBAdvGrid1.SetColumnOrder;
  DBAdvGrid1.Options := DBAdvGrid1.Options + [ goColSizing, goColMoving ];

  inif      := TINIFile.Create( cSettingsIniPath );
  colstates := inif.ReadString( cSection, cIdentFrame, '' );
  TMSLogger.TraceFormat( 'ReadString( {%s},{%s} ) = {%s}', [ cSection, cIdentFrame, colstates ] );
  inif.Free;

  if colstates <> '' then
      DBAdvGrid1.StringToColumnStates( colstates );

  for i := 0 to ADOTable1.FieldCount - 1 do
  begin
    col := DBAdvGrid1.ColumnByFieldName[ CheckListBox1.Items[ i ] ];
    if DBAdvGrid1.IsHiddenColumn( col.Index ) then
        CheckListBox1.Checked[ i ] := false;
  end;
end;

procedure TFrameDemo.ScaleForPPI( NewPPI: Integer );
begin
  inherited;
  RestoreColumnStates;
end;
1 Like
10

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11

This is a good solution as this makes the timing of the scaling the same between using a subform or using a frame.