Delphi stringgrid TAdvsTringgrid function to disable and reenable mouse clicks

Question

Is there a Delphi function to enable or disable mouse clicks for a stringgrid?

I'm using a derivation of stringgrid called Tadvstringgrid which allows coloring cells based on contens

I need to prevent mouse clicks inside a stringgrid while populating control with data from various threads.

Only disabling the control is not enough. If I click in random cells, the info gets screwed up meaning that some strings are placed in the last cell I've clicked.

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Grids, StdCtrls;

type
  TForm1 = class(TForm)
    StringGrid1: TStringGrid;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}




type
  TThread_populate_stringgrid = class(TThread)

  strict private

f_stringgrid_to_populate:Tstringgrid;
f_name:string;




  protected

    procedure Execute; override;




  public

    constructor Create(a_name:string;a_stringgrid_to_populate:Tstringgrid);




  end;



constructor TThread_populate_stringgrid.Create(a_name:string;a_stringgrid_to_populate:Tstringgrid);
begin
  inherited Create(False);
  freeonterminate:=true;
  priority:=tpNormal ;

f_name:=a_name;
f_stringgrid_to_populate:=a_stringgrid_to_populate;
end;






procedure TThread_populate_stringgrid.Execute;
begin

Synchronize(
procedure
begin



f_stringgrid_to_populate.cells[0,0]:='DATE';
f_stringgrid_to_populate.cells[1,0]:='NAME';
f_stringgrid_to_populate.cells[2,0]:='ADRESS';
f_stringgrid_to_populate.cells[3,0]:='CITY';
f_stringgrid_to_populate.cells[4,0]:='COUNTRY';


f_stringgrid_to_populate.Cols[0].Add(FormatDatetime('dd-mm-yyyy hh:mm:ss', Now));
f_stringgrid_to_populate.Cols[1].Add(f_name);
f_stringgrid_to_populate.Cols[2].Add('58 RED ROAD');
f_stringgrid_to_populate.Cols[3].Add('ENGLAND');
f_stringgrid_to_populate.Cols[3].Add('UK');



end
)
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
TThread_populate_stringgrid.Create('Andrei',form1.StringGrid1);
TThread_populate_stringgrid.Create('Matei',form1.StringGrid1);
TThread_populate_stringgrid.Create('Iulia',form1.StringGrid1);
TThread_populate_stringgrid.Create('Petru',form1.StringGrid1);
TThread_populate_stringgrid.Create('Gheorghe',form1.StringGrid1);
TThread_populate_stringgrid.Create('Tudor',form1.StringGrid1);
TThread_populate_stringgrid.Create('Cineva',form1.StringGrid1);
TThread_populate_stringgrid.Create('Altcine',form1.StringGrid1);
end;

end.

Thank you!

Answer 1

Here is the solution that works for me:

-In the main form place a "ApplicationEvents" component.

-Go to the Events section of the ApplicationEvents

-double click on "Onmessage" property and add the following procedure

procedure TForm1.deactivate_mouse_in_advstringgrid(var Msg: tagMSG;
  var Handled: Boolean);

 var
  pnt: TPoint;
  ctrl: TWinControl;
 begin
  if (
  (Msg.message = SB_VERT) OR
  (Msg.message = SB_HORZ) OR
  (Msg.message = WS_HSCROLL) OR
  (Msg.message = WS_VSCROLL) OR
  (Msg.message = WM_VSCROLL) OR
  (Msg.message = WM_MOUSEWHEEL) OR
  (Msg.message = WM_LBUTTONDOWN)   OR
  (Msg.message = WM_LBUTTONUP)   OR
  (Msg.message = WM_LBUTTONDBLCLK)   OR
  (Msg.message = WM_MBUTTONDOWN)   OR
  (Msg.message = WM_MBUTTONUP) OR
  (Msg.message = WM_MBUTTONDBLCLK) OR
  (Msg.message = WM_RBUTTONDOWN) OR
  (Msg.message = WM_RBUTTONUP) OR
  (Msg.message = WM_RBUTTONDBLCLK) OR
  (Msg.message = WM_KEYUP) OR
  (Msg.message = WM_KEYDOWN)
  )

  then
  begin

    if not GetCursorPos(pnt) then Exit;
    ctrl := FindVCLWindow(pnt);
    if Assigned(CTRL) then
   begin
      if Ctrl is TAdvstringgrid then
         begin
        // Msg.hwnd:=ctrl.Handle;
      //Msg.hwnd := advsg1.Handle;
            if thread_activ>0 then
               begin
              Msg.hwnd := 0;
              Exit;
                end
            else
              begin
              Msg.hwnd:=ctrl.Handle;
             end;
  end;
  end;
  end;
end;

If you use a Tadvstringgrid component change this code to "if Ctrl is TAdvstringgrid".

If you use a Stringgrid change this to "if Ctrl is TStringgrid".

The above procedure uses a global variable called "thread_activ" that contains the number of active threads. So if there are active threads using the Advstringgrid component the mouse clicks, mouse wheel, scroll bars, and key presses are supressed.

The thread is stored in a second unit having the following code:

unit thread_stringgrid;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Grids, StdCtrls;


type
  TThread_populate_stringgrid = class(TThread)

  strict private

f_stringgrid_to_populate:Tstringgrid;
f_name:string;


  protected

    procedure Execute; override;



  public
    CriticalSection: TRTLCriticalSection;
    constructor Create(a_name:string;a_stringgrid_to_populate:Tstringgrid);
  end;



implementation

{use the unit that holds the global vaiable "thread_activ"}
uses unit1;



constructor TThread_populate_stringgrid.Create(a_name:string;a_stringgrid_to_populate:Tstringgrid);
begin
  inherited Create(False);
  freeonterminate:=true;
  priority:=tpNormal ;

f_name:=a_name;
f_stringgrid_to_populate:=a_stringgrid_to_populate;
end;



procedure TThread_populate_stringgrid.Execute;
begin

//before the threads starts
InitializeCriticalSection(CriticalSection);

//in the thread
EnterCriticalSection(CriticalSection);
//From now on, you can safely make
//changes to the variables.

{increment variable from main unit1}
inc(unit1.thread_activ);

//End of safe block
LeaveCriticalSection(CriticalSection);

Synchronize(
procedure
begin

f_stringgrid_to_populate.cells[0,0]:='DATE';
f_stringgrid_to_populate.cells[1,0]:='NAME';
f_stringgrid_to_populate.cells[2,0]:='ADRESS';
f_stringgrid_to_populate.cells[3,0]:='CITY';
f_stringgrid_to_populate.cells[4,0]:='COUNTRY';


f_stringgrid_to_populate.Cols[0].Add(FormatDatetime('dd-mm-yyyy hh:mm:ss', Now));
f_stringgrid_to_populate.Cols[1].Add(f_name);
f_stringgrid_to_populate.Cols[2].Add('58 RED ROAD');
f_stringgrid_to_populate.Cols[3].Add('ENGLAND');
f_stringgrid_to_populate.Cols[3].Add('UK');



end
);

{eliminate thread counter from global variable "thread_activ"}
 EnterCriticalSection(CriticalSection);
  try
{decrement variable from main unit1}
dec(unit1.thread_activ);
finally
 LeaveCriticalSection(CriticalSection);
 end;

end;

(*
procedure TForm1.Button1Click(Sender: TObject);
begin
TThread_populate_stringgrid.Create('Andrei',form1.StringGrid1);
TThread_populate_stringgrid.Create('Matei',form1.StringGrid1);
TThread_populate_stringgrid.Create('Iulia',form1.StringGrid1);
TThread_populate_stringgrid.Create('Petru',form1.StringGrid1);
TThread_populate_stringgrid.Create('Gheorghe',form1.StringGrid1);
TThread_populate_stringgrid.Create('Tudor',form1.StringGrid1);
TThread_populate_stringgrid.Create('Cineva',form1.StringGrid1);
TThread_populate_stringgrid.Create('Altcine',form1.StringGrid1);
end;

*)

(*
procedure TForm1.GridDrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
var
  S: string;
  RectForText: TRect;
begin
  // Check for your cell here (in this case the cell in column 4 and row 2 will be colored)
  //if (ACol = 1) and (ARow = 1) then
  if ((ACol = 1) and (ARow>0))  then
  begin
    S := form1.StringGrid1.Cells[ACol, ARow];
    if (s='Andrei') then
      begin
    // Fill rectangle with colour
    //form1.StringGrid1.Canvas.Brush.Color := clBlack;
    form1.StringGrid1.Canvas.FillRect(Rect);
    // Next, draw the text in the rectangle
    form1.StringGrid1.Canvas.Font.Color := clGreen;
    RectForText := Rect;
    // Make the rectangle where the text will be displayed a bit smaller than the cell
    // so the text is not "glued" to the grid lines
    InflateRect(RectForText, -2, -2);
    // Edit: using TextRect instead of TextOut to prevent overflowing of text
    form1.StringGrid1.Canvas.TextRect(RectForText, S);
      end;
  end;

   // if (ACol = 2) and (ARow = 1) then
     if ((ACol = 2)and (ARow>0)) then
  begin

    S := form1.StringGrid1.Cells[ACol, ARow];
    if (s='58 RED ROAD') then
    begin

    // Fill rectangle with colour
    //form1.StringGrid1.Canvas.Brush.Color := clwhite;
    form1.StringGrid1.Canvas.FillRect(Rect);
    // Next, draw the text in the rectangle
    form1.StringGrid1.Canvas.Font.Color := clRed;
    RectForText := Rect;
    // Make the rectangle where the text will be displayed a bit smaller than the cell
    // so the text is not "glued" to the grid lines
    InflateRect(RectForText, -2, -2);
    // Edit: using TextRect instead of TextOut to prevent overflowing of text
    form1.StringGrid1.Canvas.TextRect(RectForText, S);
    end
    else
    begin
     // Fill rectangle with colour
    //form1.StringGrid1.Canvas.Brush.Color := clwhite;
    form1.StringGrid1.Canvas.FillRect(Rect);
    // Next, draw the text in the rectangle
    form1.StringGrid1.Canvas.Font.Color := clBlue;
    RectForText := Rect;
    // Make the rectangle where the text will be displayed a bit smaller than the cell
    // so the text is not "glued" to the grid lines
    InflateRect(RectForText, -2, -2);
    // Edit: using TextRect instead of TextOut to prevent overflowing of text
    form1.StringGrid1.Canvas.TextRect(RectForText, S);
    end;
  end;


     //if (ACol = 3) and (ARow = 1) then
     if ((ACol = 3)and (ARow>0)) then
  begin
    S := form1.StringGrid1.Cells[ACol, ARow];
    if s='Altcine' then
    begin
    // Fill rectangle with colour
    //form1.StringGrid1.Canvas.Brush.Color := clwhite;
    form1.StringGrid1.Canvas.FillRect(Rect);
    // Next, draw the text in the rectangle
    form1.StringGrid1.Canvas.Font.Color := clYellow;
    RectForText := Rect;
    // Make the rectangle where the text will be displayed a bit smaller than the cell
    // so the text is not "glued" to the grid lines
    InflateRect(RectForText, -2, -2);
    // Edit: using TextRect instead of TextOut to prevent overflowing of text
    form1.StringGrid1.Canvas.TextRect(RectForText, S);
    end;
  end;

 *)



end.

I hope that this helps others. Have a great day!