[SOLVED] Show memo field contents (multiline text) in dbgrid
lazarus / 16-Databases

----------------------------------------------------------------------
BigChimp · 2011-08-02 12:50

Hi,

I've got a dbgrid that loads memo fields (unlimited string). I've got
dgEditing set to false so I only show data.
The only thing that shows up is (MEMO).
Read the grid reference wiki.

Tried to:
Show multiline data as in http://wiki.lazarus.freepascal.org/Grids_Ref
erence_Page#Multilines_in_Grids. No differenceModified
gridcelleditor.lpi example to show a TMemo using the OnSelectEditor
property of the grid (code below)
Two questions:
1. What do I have to do to get the data showing correctly?
2. If I want to use the code below for something else, how do I
calculate BoundsRect? There is no aRow property in a dbgrid?

OnSelectEditor code:
Code: [Select]procedure TForm1.ResultsGridSelectEditor(Sender:
TObject; Column: TColumn;
  var Editor: TWinControl);
begin
  //GridCellMemo.BoundsRect:=ResultsGrid.CellRect(aCol,aRow);
  GridCellMemo.Text:=Column.Field.AsString;
  Editor:=GridCellMemo; //GridCellMemo.visible:=true, don't know if it
matters
end;

----------------------------------------------------------------------
Lacak2 · 2011-08-03 10:10

Quote from: BigChimp on August 02, 2011, 02:50:37 pmI've got a dbgrid
that loads memo fields (unlimited string). I've got dgEditing set to
false so I only show data.
The only thing that shows up is (MEMO).
Yes, it is how TBlobField.GetText works (uses TField.GetClassDesc).

Quote from: BigChimp on August 02, 2011, 02:50:37 pmTwo questions:
1. What do I have to do to get the data showing correctly?
I have no experience with this, but I think, that you must hook into
drawing cell and draw what you want.

----------------------------------------------------------------------
BigChimp · 2011-08-06 06:17

Thanks, Lacak2, I've solved problem 2: how to show a TMemo control as
an editor in a dbgrid. I've updated the wiki: http://wiki.lazarus.free
pascal.org/Grids_Reference_Page#Example:_How_to_set_a_memo_editor_for_
dbgrids

Comments welcome, there might be a more effective/elegant way of doing
things.

----------------------------------------------------------------------
BigChimp · 2011-09-07 11:03

Hmmm, I managed to get a bit further: now I can let a grid draw
nothing in a memo cell - just can't it to draw the proper text.

I'm using this OnDrawColumnCell event procedure in the dbgrid to try
and show memo fields:
(updated 16 September with new code)
Code: [Select]procedure TForm1.ResultsGridDrawColumnCell(Sender:
TObject; const Rect: TRect;
  DataCol: Integer; Column: TColumn; State: TGridDrawState);
// Draw memo text instead of (Memo)
// Note: grid DefaultDrawing property must be off to avoid duplicate
drawing
// To get this, I basically copied the existing DefaultDrawColumnCell
procedure
// but tested for memo first. If no memo, pass on to default
procedure.
// Maybe slower, more complicated, but it allows for changes in the
// core Lazarus DefaultDrawColumnCell procedure.
var
  OverrideDraw: boolean; //determine if we're going to override
drawing
  S: string;
  F: TField;
  DataRow: Integer;
begin
  OverrideDraw:=false;
  try
    F := Column.Field;
    if F.DataType = ftMemo then
    begin
      OverRideDraw:=true;
    end;
  except
    on E: exception do
    begin
      // We might have an inactive datalink or whatever,
      // in that case, pass on our problems to the existing
      // procedure.
      //showMessage('Exception: ' + E.Classname + '/' + E.Message);
      OverRideDraw:=false;
    end;
  end;

  if OverRideDraw=false then
  begin
    // Call normal procedure to handle drawing for us.
    ResultsGrid.DefaultDrawColumnCell(Rect,DataCol,Column,State);
  end
  else
  begin
    // Get to work displaying our memo contents
    // Basically shamelessly ripped from
    // DefaultDrawColumnCell
    // maybe fix something for first/header row
    if F<>nil then
    begin
      //DO display memo ;)
      S := F.AsString; //DisplayText will only show (Memo)
    end
    else
    begin
      S := '';
    end;
    //Actual drawing, taken from Grids.DrawCellText coding:
    ResultsGrid.Canvas.TextRect(Rect,Left,Top, S);
  end;
end;


Attached:
- project source code (hint: when started, load db2secout.txt, then
press export)
- screenshot of the problem.

Thanks for any help!

----------------------------------------------------------------------
BigChimp · 2012-03-14 10:36

Got drawing to work thanks to user137.
See http://lazarus.freepascal.org/index.php/topic,16300.0.html for
newest code.