To thoroughly customize the drawing of a DBGrid control, you have to set its DefaultDrawing property to False and handle its OnDrawColumnCell event.

The DBGrid control in this example, which is connected to the commonly used BIOLIFE table of the DBDEMOS database, has the following properties:

object DBGrid1: TDBGrid

        Align = alClient

        DataSource = DataSource1

        DefaultDrawing = False

        Font.Height = -16

        Font.name = 'MS Sans Serif'

        Font.Style = [fsBold]

        TitleFont.Height = -11

        TitleFont.Name =  'MS Sans Serif'

        TitleFont.Style = []

        OnDrawColumnCell = DBGridDrawColumnCell

end

MEMO Field

For the memo we can simply implement the memo field's OnGetText and OnSetText events. In fact, the grid will even allow editing on a memo field IF its OnSetText event is not nil or null.

( You have to double click on the Table component or Query component and at the Field Editor select the TableNotes field. Under it's event tab you'll be able to insert these codes. )

procedure TForm1.TableNotesGetText

(Sender: TField;

var Text: String;

DisplayText: Boolean)

begin

        Text := Trim(Sender.AsString);

end;

procedure TForm1.TableNotesSetText

(Sender: TField;

const Text: String);

begin

        Sender.AsString := Text;

end;

Multiple Selection

toggle th dgMultiSelect element of the options property of the grid. Once you've selected this option, a user can keep the CTRL key pressed and click with the mouse to select multiple rows of the grid, with the effect you can see below and as follows:

procedure TForm1.Button1Click

(Sender: TObject);

var

        I: Integer;

        BookmarkList: TBookmarkList;

        Bookmark: TBookmarkStr;

begin

      // store the current position

     Bookmark := Table1.Bookmark;

try

        // empty the list box

        ListBox1.Items.Clear;

        // get the selected rows of the grid

        BookmarkList := DBGrid1.SelectedRows;

        for I := 0 to

            BookmarkList.count - 1 do

        begin

        // for each, move the table to that record

        Table1.Bookmark := BookmarkList[I];

        // add the name field to the listbox

        ListBox1.Items.Add

        (Table1.FieldByName ('Name').AsString);        

        end;

finally

        // go back to the initial record

        Table1.Bookmark := Bookmark;

end;

end;

Color Me Red

The OnDrawColumnCell event handler is called once for every cell of the grid and has several parameters, including the rectangle corresponding to the cell, the index of the column we have to draw, the column itself and the status of the cell. How can we set the color of specific cell to red ? see code below:

procedure TForm1.DBGridDrawColumnCell

(Sender: TObject;

const Rect: TRect; DataCol: Integer;

Column: TColumn; State: TGridDrawState);

begin

     // red font color if length > 100

     if (COlumn.Field = Table1Lengthcm)

        and

        (Table1Lengthcm.AsInteger > 100)

        then

        DBGrid1.Canvas.Font.Color := clRed;

        // default drawing

        DBGrid1.DefaultDrawDataCell (Rect, Column.Field, State);        

end;

Note: 

    Table1Lengthcm is a field

    column in DBGrid1

Image

For the image, the simplest approach is to create a temporary TBitmap object, assign the graphics field to it, and paint the bitmap to the Canvas of the grid.

var

        Bmp: TBitmap;

        OutRect: TRect;

        BmpWidth: Integer;

begin

        // default output rectangle

        OutRect := Rect;

        If Column.Field = TableCommon_Name

        then begin

        // draw the image

        Bmp := TBitmap.create;

        try

        Bmp.Assign(TableGraphic);

        BmpWidth := (Rect.Bottom - Rect.Top) * 2;

        OutRect.Right := Rect.Left + BmpWidth;

        DBGrid1.Canvas.StretchDraw (OutRect, Bmp);

        finally

                Bmp.Free;

        end;

        // reset output rectangle,

        // leaving space for the

        // graphic

        OutRect := Rect;

        OutRect.Left := OutRect.Left + BmpWidth;

        end;

As you can see in the code above, the program shows the image in a small rectangle on the left of the grid cell and then changes the output rectangle to the remaining area before activating the default drawing. to be inserted at the DBGridDrawColumnCell procedure, also.