I've written some code which colours individual cells on my stringgrid, within my delphi application, according to a list of data.
I now need to write some code in the OnDblClick event on my stringgrid which deduces whether or not a cell is coloured and then proceeds according to the result found. For instance:
DOUBLE CLICK CELL
IS CELL COLOURED
YES > PROCEED A
NO > PROCEED B
Store the color at the time you draw it into the predefined TStringGrid.Objects property. When you need to retrieve it, you can get it back from the Column and Row coordinates. Here's a trivial example that stores either clWhite or clBlack in the Objects for the cell based on whether or not it's an odd-numbered column, and simply displays the stored value as a string when the cell is selected. It should get you started.
procedure TForm1.FormCreate(Sender: TObject);
var
r, c: Integer;
const
ColorSel: array[Boolean] of TColor = (clWhite, clBlack);
begin
StringGrid1.RowCount := 10;
StringGrid1.ColCount := 6;
for c := 1 to StringGrid1.ColCount - 1 do
for r := 1 to StringGrid1.RowCount - 1 do
begin
StringGrid1.Cells[c, r] := Format('C: %d R: %d', [c, r]);
StringGrid1.Objects[c, r] := TObject(ColorSel[Odd(c)]);
end;
end;
procedure TForm1.StringGrid1SelectCell(Sender: TObject; ACol, ARow: Integer;
var CanSelect: Boolean);
begin
ShowMessage(ColorToString(TColor(StringGrid1.Objects[ACol, ARow])));
end;
You can use this in the OnMouseUp event easily to detect what color is in the cell. Remove the StringGrid1SelectCell (using the Object Inspector, just remove the value for the event) and add this as the OnMouseUp event for the grid instead:
procedure TForm1.StringGrid1MouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
var
Col, Row: Integer;
begin
StringGrid1.MouseToCell(X, Y, Col, Row);
if (Col > -1) and (Row > -1) then
ShowMessage(ColorToString(TColor(StringGrid1.Objects[Col, Row])));
end;
Handling the double-click then becomes pretty easy (thanks to #TLama for a big assist):
procedure TForm1.StringGrid1DblClick(Sender: TObject);
var
IsDefaultColor: Boolean;
CurrCellColor: TColor;
CurrCol, CurrRow: Integer;
begin
// Save typing by grabbing the currently selected cell col/row
CurrCol := StringGrid1.Col;
CurrRow := StringGrid1.Row;
// Get the stored color for the selected cell
CurrCellColor := TColor(StringGrid1.Objects[CurrCol, CurrRow]);
// See if it's been painted a different color than the default
IsDefaultColor := (CurrCellColor = StringGrid1.Color);
if not IsDefaultColor then
HandleDifferentColorCell
else
HandleNormalColorCell;
end;
Note that if you're choosing not to change the color for a cell, you should still assign the default color of the cell to the Objects[Column, Row] so that there's something meaningful there in order to avoid an improper conversion when retrieving the value.
Related
How can I make all my grids look the same way all over my forms?
I want to implement an alternate row color that must be applied on all grids of my project. Is it possible without adding the same DrawColumnCell event code for every grid?
I want to avoid adding the same code for each of my grids. I have like 30 grids in my project and multiplied by 13 rows of code it just adds a lot of code lines to my project making it "unfriendly".
I am looking for a solution that will only add 13 lines of code to the project, not 390 lines.
My formatting code looks like this (for example):
procedure TDBGrid.DBGrid1DrawColumnCell(Sender: TObject;const Rect: TRect;DataCol: Integer;Column: TColumn;State: TGridDrawState) ;
var
grid : TDBGrid;
row : integer;
begin
grid := sender as TDBGrid;
row := grid.DataSource.DataSet.RecNo;
if Odd(row) then
grid.Canvas.Brush.Color := clSilver
else
grid.Canvas.Brush.Color := clDkGray;
grid.DefaultDrawColumnCell(Rect, DataCol, Column, State) ;
end;
Probably I would need to extend the DBGrid somehow, but I do not know exactly how nor how to look for a solution for this on google
I tried to hack the DBGRid inside each form like this:
type
TDBGrid = class(DBGrids.TDBGrid)
protected
procedure DrawColumnCell(const Rect: TRect; DataCol: Integer;Column: TColumn; State: TGridDrawState); override;
end;
...
procedure TDBGrid.DrawColumnCell(const Rect: TRect; DataCol: Integer;Column: TColumn; State: TGridDrawState) ;
var
grid : TDBGrid;
row : integer;
begin
row := 2;//grid.DataSource.DataSet.RecNo;
if Odd(row) then
Canvas.Brush.Color := clSilver
else
Canvas.Brush.Color := clDkGray;
DefaultDrawColumnCell(Rect, DataCol, Column, State) ;
end;
I can do this but I cannot access the sender, so I can access the dataset and know which record to color and which not (odd and even).
And this is a poor approach anyways since I will have to do it on every form, so it's not really a solution
Any ideas?
Thank you
If you put something like this in your datamodule, and assign it to the OnDrawColumnCell of every DBGrid, it seems to work (see notes that follow):
procedure TDataModule1.DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;
DataCol: Integer; Column: TColumn; State: TGridDrawState);
const
RowColors: array[Boolean] of TColor = (clSilver, clDkGray);
var
OddRow: Boolean;
begin
// Safety check, although it really isn't needed; no other control accepts
// this event handler definition, AFAIK, so the only way to call it with the
// wrong Sender type would be to do so in your own code manually. In my own
// code, I'd simply leave out the check and let the exception happen; if I
// was stupid enough to do so, I'd want my hand slapped rudely.
if (Sender is TDBGrid) then
begin
OddRow := Odd(TDBGrid(Sender).DataSource.DataSet.RecNo);
TDBGrid(Sender).Canvas.Brush.Color := RowColors[OddRow];
TDBGrid(Sender).DefaultDrawColumnCell(Rect, DataCol, Column, State);
end;
end;
A couple of notes:
First, you should avoid using TDataSet.RecNo in the first place, because post-BDE datasets don't typically have this value available. Accessing it (particularly on large or query-based datasets) causes a major performance hit to your application. Of course, not using it means that you can't use this solution. A better solution would be to use a handler for the dataset's BeforeScroll or AfterScroll event that toggled a boolean available to this code instead, and use that instead of the test for Odd(RecNo), or if the dataset is only used for displaying in the DBGrid, use the TDataSet.Tag in the AfterScroll event to track the row's odd/even state using
OddRow := Boolean(DataSet.Tag);
DataSet.Tag := Ord(not OddRow);
Add DBGrids to the uses clause of your datamodule, and manually declare the above event in the published section so that it's available to all units that use the datamodule. You can then assign it in the Object Inspector Events tab as usual from those units.
This does not properly handle the TGridDrawState (nor does your initial code). You'll need to add handling for that yourself, as that wasn't what you asked here.
Depending on which color you want for odd and even rows, you may want to reverse the order of the colors in RowColors.
I prefer the repeated typecasts so that it's clear what the code is doing. If it bothers you, you can simply declare a local variable instead:
var
OddRow: Boolean;
Grid: TDBGrid;
begin
if (Sender is TDBGrid) then
begin
Grid := TDBGrid(Sender);
OddRow := Odd(Grid.DataSource.DataSet.RecNo);
...
end;
end;
This works for Delphi XE7
type
TDBGrid=Class(Vcl.DBGrids.TDBGrid)
procedure WMVScroll(var Message: TWMVScroll); message WM_VSCROLL;
end;
procedure TDBGrid.WMVScroll(var Message: TWMVScroll);
begin
Self.Invalidate;
inherited;
end;
procedure TForm1. DBGrid1MouseWheel(Sender: TObject; Shift: TShiftState;
WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
begin
if Sender is TDBGrid then
(Sender as TDBGrid).Invalidate;
end;
procedure TForm1.DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;
DataCol: Integer; Column: TColumn; State: TGridDrawState);
const
MyRowColors : array[Boolean] of TColor = (clLime, clMoneyGreen);
var
RowNo : Integer;
OddRow : Boolean;
S : string;
begin
if Sender is TDBGrid then begin
with (Sender as TDBGrid) do begin
if (gdSelected in State) then begin
// Farbe für die Zelle mit dem Focus
// color of the focused row
Canvas.Brush.Color := clblue;
end
else begin
// count := trunc((Sender as TDBGrid).Height div (Rect.Bottom - Rect.Top));
// RowNo := (Sender as TDBGrid).Height div Rect.Top;
RowNo := Rect.Top div (Rect.Bottom - Rect.Top);
OddRow := Odd(RowNo);
Canvas.Brush.Color := MyRowColors[OddRow];
// Font-Farbe immer schwarz
// font color always black
Canvas.Font.Color := clBlack;
Canvas.FillRect(Rect);
// Denn Text in der Zelle ausgeben
// manualy output the text
if Column.Field <> nil then begin
S := Column.Field.AsString;
Canvas.TextOut(Rect.Left + 2, Rect.Top + 1, S);
// Canvas.TextOut(Rect.Left + 2, Rect.Top + 1, 'Column.Field.AsString');
end;
end;
end
end;
end;
I know that i can set custom colors to items when i add them to the list using OnDraw Events but i want to change colors of the items at a certain point after they are already in the list.
Is there a way to do this ?
To redraw only certain items use the UpdateItems method. It has two input parameters where you can specify the range of the items to be redrawn. If you are going to redraw only one item, then just specify that one item index as a range.
In this example I'm storing the color of the item into the TListItem.Data property and fading this color in the timer's event. After changing the value I call the UpdateItems function which force the draw item event to fire. And yes, without DoubleBuffered set, it flickers (even when you set the timer's interval e.g. to 500ms).
procedure TForm1.FormCreate(Sender: TObject);
begin
ListView1.AddItem('Item 1', TObject(clWhite));
ListView1.AddItem('Item 2', TObject(clWhite));
ListView1.AddItem('Item 3', TObject(clWhite));
Timer1.Enabled := True;
end;
procedure TForm1.ListView1CustomDrawItem(Sender: TCustomListView;
Item: TListItem; State: TCustomDrawState; var DefaultDraw: Boolean);
begin
ListView1.Canvas.Brush.Color := TColor(Item.Data);
end;
procedure TForm1.Timer1Timer(Sender: TObject);
var
C: Byte;
I: TColor;
procedure ChangeItemColor;
begin
I := TColor(ListView1.Items[0].Data);
C := GetRValue(I);
if C < 150 then C := 255 else Dec(C);
I := RGB(C, C, C);
ListView1.Items[0].Data := TObject(I);
end;
begin
// color change
ChangeItemColor;
// repaint of the item with index 1
ListView1.UpdateItems(1, 1);
end;
All is in the title.
How can we also make an officehint customisable for each row. Mean when mousemove on a row, display the information of this record (from a db query).
Thanks
You can color individual cells using the CellProperties property of the grid. You can use this to color an entire row:
var
RowIndex: Integer;
ColIndex: Integer;
with MyDBAdvGrid do
begin
// you choose the row index; you may want to iterate all rows to
// color each of them
RowIndex := 2;
// now iterate all (non-fixed, visible) cells in the row and color each cell
for ColIndex := FixedCols to ColCount - 1 do
begin
CellProperties[ColIndex, RowIndex].BrushColor := clYellow;
CellProperties[ColIndex, RowIndex].FontColor := clGreen;
end;
end;
To fill your office hint with record data I would suggest updating it when the user moves the mouse. Use the MouseToCell function to get row and column under the mouse, then use MyDBAdvGrid.AllCells[ColIndex, RowIndex] to access the cell content.
An Alternative to Heinrich answer is to use the OnGetCellColor event.
This can be use like so:
procedure TDBAdvGrid.DBGridGetCellColor(Sender: TObject; ARow,
ACol: Integer; AState: TGridDrawState; ABrush: TBrush; AFont: TFont);
begin
if (your condition) then ABrush.Color := clRed;
end;
Similarly for the hint:
procedure TDBAdvGrid.DBGridGridHint(Sender: TObject; ARow, ACol: Integer;
var hintstr: String);
begin
hintstr := 'your hint text';
end;
I have a TStringGrid where the selected row (max 1, no multi-select) should always have a different background colo(u)r.
I set the DefaultDrawing property to false, and provide a method for the OnDrawCell event, shown below - but it is not working. I can't even describe exactly how it is not working; I supect that if I could I would already have solved the problem. Suffice it to say that instead of having complete rows all with the same background colour it is a mish-mash. Muliple rows have some cells of the "Selected" colour and not all cells of the cselected row have the selected colour.
Note that I compare the cell's row with the strnggrid's row; I can't check the cell state for selected since only cell of the selected row is selected.
procedure TForm1.DatabaseNamesStringGridDrawCell(Sender: TObject;
ACol, ARow: Integer;
Rect: TRect;
State: TGridDrawState);
var cellText :String;
begin
if gdFixed in State then
DatabaseNamesStringGrid.Canvas.Brush.Color := clBtnFace
else
if ARow = DatabaseNamesStringGrid.Row then
DatabaseNamesStringGrid.Canvas.Brush.Color := clAqua
else
DatabaseNamesStringGrid.Canvas.Brush.Color := clWhite;
DatabaseNamesStringGrid.Canvas.FillRect(Rect);
cellText := DatabaseNamesStringGrid.Cells[ACol, ARow];
DatabaseNamesStringGrid.Canvas.TextOut(Rect.Left + 2, Rect.Top + 2, cellText);
end;
if you are trying of paint the selected row or cell with a different color you must check for the gdSelected value in the state var.
procedure TForm1.DatabaseNamesStringGridDrawCell(Sender: TObject;
ACol, ARow: Integer;
Rect: TRect;
State: TGridDrawState);
var
AGrid : TStringGrid;
begin
AGrid:=TStringGrid(Sender);
if gdFixed in State then //if is fixed use the clBtnFace color
AGrid.Canvas.Brush.Color := clBtnFace
else
if gdSelected in State then //if is selected use the clAqua color
AGrid.Canvas.Brush.Color := clAqua
else
AGrid.Canvas.Brush.Color := clWindow;
AGrid.Canvas.FillRect(Rect);
AGrid.Canvas.TextOut(Rect.Left + 2, Rect.Top + 2, AGrid.Cells[ACol, ARow]);
end;
Do you have run-time themes enabled? Run-time themes override any colour scheme you try to enforce for Windows Vista and up.
When a new cell is selected in a stringgrid only the previous and the new selected cell are invalidated. Thus the remaining cells of the previous and new row are not redrawn, giving the effect you describe.
One workaround would be to call InvalidateRow for both affected rows, but this is a protected method and you have to find a way to reach this method from an OnSelectCell event handler. Depending on your Delphi version there are different ways to accomplish that.
The cleanest way would be to derive from TStringGrid, but in most cases this is not feasible. With a newer Delphi version you can use a class helper to achieve this. Otherwise you have to rely on the usual protected hack.
This works for me
procedure TFmain.yourStringGrid(Sender: TObject; ACol, ARow: Integer; Rect: TRect;
State: TGridDrawState);
var
md: integer;
begin
with yourStringGrid do
begin
if yourStringGrid,Row = ARow then
Canvas.Brush.Color:= clYellow //your highlighted color
else begin
md := Arow mod 2;
if md <> 0 then Canvas.Brush.Color:= $00BADCC1 else //your alternate color
Canvas.Brush.Color:= clwhite;
end;
Canvas.FillRect(Rect);
Canvas.TextOut(L, Rect.top + 4, cells[ACol, ARow]);
end;
end;
Refresh the grid
procedure TFmain.yourStringGridClick(Sender: TObject);
begin
yourStringGrid.Refresh;
end;
Note: Has a little latency, but otherwise works great.
(Used in Delphi XE2)
In a previous question here I asked about drag n drop within the gridpanel.
Drag N Drop controls in a GridPanel
The question I have next is that I am having weird behavior whenever I try to move controls diagonally when they are near other controls. Controls that not suppose to move are shifting cells. Up and down, sideways it is fine. But diagonal moves, when the moved cell contents are on the same row/column with other cells which hold controls will cause unexpected shifts. I have tried beginupdate/endupdate the shifts still happen. There is a LOCK function for the gridpanel but lock anything. It happens when the drop is on an empty cell, and even cells that already have contents.
here is the test project (Delphi 2010 w/o exe)
http://www.mediafire.com/?xmrgm7ydhygfw2r
type
TForm1 = class(TForm)
GridPanel1: TGridPanel;
btn1: TButton;
btn3: TButton;
btn2: TButton;
lbl1: TLabel;
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
procedure GridPanelDragDrop(Sender, Source: TObject; X, Y: Integer);
procedure btnDragOver(Sender, Source: TObject; X, Y: Integer;
State: TDragState; var Accept: Boolean);
procedure btnDragDrop(Sender, Source: TObject; X, Y: Integer);
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure SetColumnWidths(aGridPanel: TGridPanel);
var
i,pct: Integer;
begin
aGridPanel.ColumnCollection.BeginUpdate;
pct:=Round(aGridPanel.ColumnCollection.Count/100);
for i := 0 to aGridPanel.ColumnCollection.Count - 1 do begin
aGridPanel.ColumnCollection[i].SizeStyle := ssPercent;
aGridPanel.ColumnCollection[i].Value := pct;
end;
aGridPanel.ColumnCollection.EndUpdate;
end;
procedure SetRowWidths(aGridPanel: TGridPanel);
var
i,pct: Integer;
begin
aGridPanel.RowCollection.BeginUpdate;
pct:=Round(aGridPanel.RowCollection.Count/100);
for i := 0 to aGridPanel.RowCollection.Count - 1 do begin
aGridPanel.RowCollection[i].SizeStyle := ssPercent;
aGridPanel.RowCollection[i].Value := pct;
end;
aGridPanel.RowCollection.EndUpdate;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
btn1.OnDragOver := btnDragOver;
btn2.OnDragOver := btnDragOver;
btn3.OnDragOver := btnDragOver;
GridPanel1.OnDragOver := btnDragOver;
GridPanel1.OnDragDrop := GridPanelDragDrop;
btn1.OnDragDrop := btnDragDrop;
btn2.OnDragDrop := btnDragDrop;
btn3.OnDragDrop := btnDragDrop;
SetColumnWidths(GridPanel1);
SetRowWidths(GridPanel1);
end;
procedure TForm1.btnDragOver(Sender, Source: TObject; X, Y: Integer;
State: TDragState; var Accept: Boolean);
begin
Accept := (Source is TButton);
end;
procedure TForm1.btnDragDrop(Sender, Source: TObject; X, Y: Integer);
var
src_x,src_y, dest_x, dest_y: Integer;
btnNameSrc,btnNameDest: string;
src_ctrlindex,dest_ctrlindex:integer;
begin
if Source IS tBUTTON then
begin
//GridPanel1.ColumnCollection.BeginUpdate;
btnNameSrc := (Source as TButton).Name;
btnNameDest := (Sender as TButton).Name;
src_ctrlindex := GridPanel1.ControlCollection.IndexOf(Source as tbutton);
src_x := GridPanel1.ControlCollection.Items[src_ctrlindex].Column;
src_y := GridPanel1.ControlCollection.Items[src_ctrlindex].Row;
dest_ctrlindex := GridPanel1.ControlCollection.IndexOf(Sender as tbutton);
dest_x := GridPanel1.ControlCollection.Items[dest_ctrlindex].Column;
dest_y := GridPanel1.ControlCollection.Items[dest_ctrlindex].Row;
GridPanel1.ControlCollection[src_ctrlindex].Column := dest_x;
GridPanel1.ControlCollection[src_ctrlindex].Row := dest_y;
//GridPanel1.ColumnCollection.EndUpdate;
lbl1.Caption := Format('"%s" from cell %d:%d to Cell %s=%d:%d', [btnNameSrc,src_x,src_y,btnNameDest,dest_x,dest_y]);
end;
end;
procedure TForm1.GridPanelDragDrop(Sender, Source: TObject; X, Y: Integer);
var
DropPoint: TPoint;
CellRect: TRect;
i_col, i_row, src_x,src_y, dest_x, dest_y: Integer;
btnNameSrc,btnNameDest: string;
src_ctrlindex:integer;
begin
if Source is tbutton then
begin
btnNameSrc := (Source as TButton).Name;
btnNameDest := '';
src_ctrlindex := GridPanel1.ControlCollection.IndexOf(Source as tbutton);
src_x := GridPanel1.ControlCollection.Items[src_ctrlindex].Column;
src_y := GridPanel1.ControlCollection.Items[src_ctrlindex].Row;
DropPoint := Point(X, Y);
for i_col := 0 to GridPanel1.ColumnCollection.Count-1 do
for i_row := 0 to GridPanel1.RowCollection.Count-1 do
begin
CellRect := GridPanel1.CellRect[i_col, i_row];
if PtInRect(CellRect, DropPoint) then
begin
// Button was dropped over Cell[i_col, i_row]
dest_x := i_col;
dest_y := i_row;
Break;
end;
end;
lbl1.Caption := Format('"%s" from cell %d:%d to Cell %s=%d:%d', [btnNameSrc,src_x,src_y,btnNameDest,dest_x,dest_y]);
GridPanel1.ControlCollection[src_ctrlindex].Column := dest_x;
GridPanel1.ControlCollection[src_ctrlindex].Row := dest_y;
end;
end;
This is not about dragging, when an item's both column and row are changing the change occurs in two steps. With your code, first the column, then the row. If in the column change, f.i., there happens to be already an other control, this other control is pushed aside, even if its cell is not the ultimate location of the target cell of the moving control.
Begin/EndUpdate will not work, the control collection never checks the update count. What can you do is to use a protected hack to access the control item's InternalSetLocation method. This method has a 'MoveExisting' parameter which you can pass 'False'.
type
THackControlItem = class(TControlItem);
procedure TForm1.GridPanelDragDrop(Sender, Source: TObject; X, Y: Integer);
var
[...]
begin
if Source is tbutton then
begin
[...]
lbl1.Caption := Format('"%s" from cell %d:%d to Cell %s=%d:%d', [btnNameSrc,src_x,src_y,btnNameDest,dest_x,dest_y]);
THackControlItem(GridPanel1.ControlCollection[src_ctrlindex]).
InternalSetLocation(dest_x, dest_y, False, False);
// GridPanel1.ControlCollection[src_ctrlindex].Column := dest_x;
// GridPanel1.ControlCollection[src_ctrlindex].Row := dest_y;
end;
end;
You might need to test if the target cell is empty or not before calling 'InternalSetLocation' depending on what you expect to be the correct control movement.
I use a quite different way to do the Job... Create a whole unit just to add a method to ExtCtrls.TControlCollection without touching unit ExtCtrls (first hack) and make such method use InternalSetLocation (second hack). I also explain both hacks on this post.
Then i only need to add such unit to implementation uses section (before gridpanel declaration) and call the method i created... very simple to use.
Here is how i do it, step by step:
I include such unit i maded for such job to the project (add file)
I add to my TForm interface uses section such unit (or where i need it)
I use my method AddControlAtCell instead of ExtCtrls.TControlCollection.AddControl
Here is the unit i had created for such job, save it as unitTGridPanel_WithAddControlAtCell:
unit unitTGridPanel_WithAddControlAtCell;
interface
uses
Controls
,ExtCtrls
;
type TGridPanel=class(ExtCtrls.TGridPanel)
private
public
procedure AddControlAtCell(AControl:TControl;AColumn:Integer;ARow:Integer); // Add Control on specifed cell, if there already exists a Control it will be deleted
end;
implementation
uses
SysUtils
;
type
THackControlItem=class(TControlItem); // To get internal access to InternalSetLocation procedure
procedure TGridPanel.AddControlAtCell(AControl:TControl;AColumn:Integer;ARow:Integer);
var
TheControlItem:TControlItem; // To let it be added in a specified cell, since ExtCtrls.TControlCollection.AddControl contains multiply BUGs
begin // Add Control on specifed cell, if there already exists a Control it will be deleted
if (-1<AColumn)and(AColumn<ColumnCollection.Count) // Cell with valid Column
and // Cell inside valid range
(-1<ARow)and(ARow<RowCollection.Count) // Cell with valid Row
then begin // Valid cell, must check if there is already a control
if (Nil<>ControlCollection.ControlItems[AColumn,ARow]) // Check if there are any controls
and // A control is already on the cell
(Nil<>ControlCollection.ControlItems[AColumn,ARow].Control) // Check if cell has a control
then begin // There is already a control, must be deleted
ControlCollection.Delete(ControlCollection.IndexOf(ControlCollection.ControlItems[AColumn,ARow].Control)); // Delete the control
end;
TheControlItem:=ControlCollection.Add; // Create the TControlItem
TheControlItem.Control:=TControl(AControl); // Put the Control in the specified cell without altering any other cell
THackControlItem(ControlCollection.Items[ControlCollection.IndexOf(AControl)]).InternalSetLocation(AColumn,ARow,False,False); // Put the ControlItem in the cell without altering any other cell
end
else begin // Cell is out of range
raise Exception.CreateFmt('Cell [%d,%d] out of range on ''%s''.',[AColumn,ARow,Name]);
end;
end;
end.
I hope the comments are enough clear, please read them to understand why and how i do it.
Then, when i need to add a control to the gridpanel at a specified cell i do the next simple call:
TheGridPanel.AddControlAtCell(TheControl,ACloumn,ARow); // Add it at desired cell without affecting other cells
A very, very basic example of adding a runtime newly created TCheckBox at a specific cell could be like this:
// AColumn is of Type Integer
// ARow is of Type Integer
// ACheckBox is of Type TCheckBox
// TheGridPanel is of Type TGridPanel
ACheckBox:=TCheckBox.Create(TheGridPanel); // Create the Control to be added (a CheckBox)
ACheckBox.Visible:=False; // Set it to not visible, for now (optimization on speed, e tc)
ACheckBox.Color:=TheGridPanel.Color; // Just to use same background as on the gridpanel
ACheckBox.Parent:=TheGridPanel; // Set the parent of the control as the gridpanel (mandatory)
TheGridPanel.AddControlAtCell(ElCheckBox,ACloumn,ARow); // Add it at desired cell without affecting other cells
ElCheckBox.Visible:=True; // Now it is added, make it visible
ElCheckBox.Enabled:=True; // And of course, ensure it is enabled if needed
Please Note that i use this two Hacks:
type THackControlItem let me access the method InternalSetLocation.
type TGridPanel=class(ExtCtrls.TGridPanel) let me add a method to ExtCtrls.TGridPanel without even touching (neither needing source of ExtCtrls)
Important: Also note that i mention it requieres to add the unit to the uses of the interface of each form where you want to use the method AddControlAtCell; that is for normal people, advanced people could also create another unit, etc... the 'concept' is to have the unit on the uses before the declaration of the GridPanel where you wnat to use it... example: if GridPanel is putted at design time on a form... it must go on implementation uses of such form unit.
Hope this helps some one else.
The solution below works without any kind of hacking.
My code is in C++ Builder but i think it is simply to understand for Delphi users because it rely only on VCL functions.
PS: note that I drag TPanels instead of TButtons (a very minor change).
void TfrmVCL::ButtonDragDrop(TObject *Sender, TObject *Source, int X, int Y)
{
TRect CurCellRect;
TRect DestCellRect;
int Col;
int Row;
int destCol; int destRow;
int srcIndex; int destIndex;
TPanel *SrcBtn;
TPanel *DestBtn;
SrcBtn = dynamic_cast<TPanel *>(Source);
if (SrcBtn)
{
int ColCount = GridPnl->ColumnCollection->Count ;
int RowCount = GridPnl->RowCollection->Count ;
// SOURCE
srcIndex = GridPnl->ControlCollection->IndexOf( SrcBtn );
// DESTINATION
// we get coordinates of the button I drag onto
DestBtn= dynamic_cast<TPanel *>(Sender);
if (!DestBtn) return;
destIndex = GridPnl->ControlCollection->IndexOf( DestBtn );
destCol = GridPnl->ControlCollection->Items[ destIndex ]->Column; // the column for the dragged button
destRow = GridPnl->ControlCollection->Items[ destIndex ]->Row;
DestCellRect = GridPnl->CellRect[ destCol ][ destRow ];
// Check all cells
for ( Col = 0 ; Col < ColCount ; Col++ )
{
for ( Row = 0 ; Row < RowCount ; Row++ )
{
// Get the bounding rect for this cell
CurCellRect = GridPnl->CellRect[ Col ][ Row ];
if (IntersectRect_ForReal(DestCellRect, CurCellRect))
{
GridPnl->ControlCollection->Items[srcIndex]->SetLocation(Col, Row, false);
return;
}
}
}
}
}