Wsrtjtyk

I have StringGrid with 2 columns: Player and Scores. I have to sort this table looking at the score of a player.

This is the situation. I have tried with a StringGrid3.SortColRow(true, 1); but it sorts only the string value. If I have numbers like [1, 4, 12, 3] the sorted StringGrid becomes [a, 12, 3, 4].

I have to sort the Integer value, not the string one. Also, my problem is that I must move the player's name too with the numbers (as you can see in the picture above).

How could I do it?

You might write a comparator which is trying to sort by Numbers if both compared values are numbers. With casting the Stringgrid to its ancestor TCustomgrid you are able to use the procedure MoveRow to swap rows. An example showing sorting over many columns could look like this:

unit StringGridSortEnh;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, Grids, StdCtrls;



type

  TForm1 = class(TForm)

    StringGrid1: TStringGrid;

    Button1: TButton;

    Button2: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}

type

  TMoveSG = class(TCustomGrid);

  TSortInfo = Record

    col: Integer;

    asc: Boolean;

  End;



function CompareNumber(i1, i2: Double): Integer;

// Result: -1 if i1 < i2, 1 if i1 > i2, 0 if i1 = i2

begin

  if i1 < i2 then

    Result := -1

  else if i1 > i2 then

    Result := 1

  else

    Result := 0;

end;



// Compare Strings if possible try to interpret as numbers

function CompareValues(const S1, S2 : String;asc:Boolean): Integer;

var

  V1, V2 : Double;

  C1, C2 : Integer;

begin

  Val(S1, V1, C1);

  Val(S2, V2, C2);

  if (C1 = 0) and (C2 = 0) then  // both as numbers

     Result := CompareNumber(V1, V2)

  else  // not both as nubers

     Result := AnsiCompareStr(S1, S2);

  if not Asc then Result := Result * -1;



end;



procedure SortGridByCols(Grid: TStringGrid; ColOrder: array of TSortInfo; Fixed: Boolean);

var

  I, J, FirstRow: Integer;

  Sorted: Boolean;



  function Sort(Row1, Row2: Integer): Integer;

  var

    C: Integer;

  begin

    C := 0;

    Result := CompareValues(Grid.Cols[ColOrder[C].col][Row1], Grid.Cols[ColOrder[C].col][Row2],ColOrder[C].asc);

    if Result = 0 then

    begin

      Inc(C);

      while (C <= High(ColOrder)) and (Result = 0) do

      begin

        Result := CompareValues(Grid.Cols[ColOrder[C].col][Row1], Grid.Cols[ColOrder[C].col][Row2],ColOrder[C].asc);

        Inc(C);

      end;

    end;

  end;



begin

  for I := 0 to High(ColOrder) do

    if (ColOrder[I].col < 0) or (ColOrder[I].col >= Grid.ColCount) then

      Exit;



  if Fixed then

    FirstRow := 0

  else

    FirstRow := Grid.FixedRows;



  J := FirstRow;

  Sorted := True;

  repeat

    Inc(J);

    for I := FirstRow to Grid.RowCount - 2 do

      if Sort(I, I + 1) > 0 then

      begin

        TMoveSG(Grid).MoveRow(i + 1, i);

        Sorted := False;

      end;

  until Sorted or (J >= Grid.RowCount + 1000);

  Grid.Repaint;

end;



procedure TForm1.Button1Click(Sender: TObject);

const // we want to use only 4 columns

  MyArray: array[0..3] of TSortInfo =

    ((col: 1; asc: true),

     (col: 2; asc: true),

     (col: 3; asc: true),

     (col: 4; asc: false)

     );

begin

  SortGridByCols(StringGrid1,MyArray,true);

end;



procedure TForm1.Button2Click(Sender: TObject);

const  // we want to use only one column

  MyArray: array[0..0] of TSortInfo = ((col: 1; asc: true));

begin

  SortGridByCols(StringGrid1,MyArray,true);

end;



end.

In Lazarus you can define how the cells of a TStringGrid sort using the OnCompareCells event, see the following link for and example of how to do this with numbers and more info.

http://wiki.lazarus.freepascal.org/Grids_Reference_Page#Sorting_Columns_or_Rows

If you want to sort the rows in Delphi you would need to re-implement the SortColRow method from Lazarus.

You can do this with a class helper

Note that this has NOT been tested fully!

The AnsiCompareStr in the below procedures can then be swamped out to compare integers.

type

  TStringGridHelper = class helper  for TStringGrid

  public

    procedure SortColRow(IsColumn: Boolean; Index: Integer); overload;

    procedure SortColRow(IsColumn: Boolean; Index: Integer; FromIndex: Integer; ToIndex: Integer); overload;

end;





implementation





procedure TStringGridHelper.SortColRow(IsColumn: Boolean; Index: Integer);

begin

     if (IsColumn) then SortColRow(IsColumn, Index, FixedCols, ColCount - 1)

     else SortColRow(IsColumn, Index, FixedRows, RowCount - 1)

end;



procedure TStringGridHelper.SortColRow(IsColumn: Boolean; Index: Integer; FromIndex: Integer; ToIndex: Integer);

    var i, p, x, c : Integer;

    s1, s2 : String;

begin



    if (IsColumn) then

    begin

        for x := ToIndex downto FromIndex do

            for I := FromIndex to ToIndex - 1 do

            begin

                s1 := Cells[i, index];

                s2 := Cells[i + 1, index];



                c := AnsiCompareStr(s1, s2);

                if (c > 0) then

                begin

                    p := i + 1;

                    p := Max(p, FromIndex);

                    p := Min(p, ToIndex);



                    MoveColumn(i, p);

                end;

            end;

    end

    else

    begin

        for x := ToIndex downto FromIndex do

            for I := FromIndex to ToIndex - 1 do

            begin

                s1 := Cells[index, i];

                s2 := Cells[index, i + 1];

                c := AnsiCompareStr(s1, s2);

                if (c > 0) then

                begin

                    p := i + 1;

                    p := Max(p, FromIndex);

                    p := Min(p, ToIndex);



                    MoveRow(i, p);

                end;

            end;

    end;

end;

Are you using Lazarus instead of Delphi? I'm not aware of a sorting feature in the standard Delphi StringGrid implementation.

The issue is that the StringGrid is just that, a grid of Strings. It has no understanding that the strings are in fact numbers, so it can only sort them alphabetically.

If you are looking for a more complex sorting ability than the grid provides naturally you have a couple of choices. Either override the TStringGrid class and produce your own specialised version that sorts how you want it to (i'm afraid i don't have the Lazarus source code to hand to give you more specific instructions), or you can simply sort the records before you put them into the grid.

For instance, if you have a TPlayer class that represents your player and their scores then you can use TList.Sort(..) to sort it however you like before you loop over and populate the grid.

// 

// Sort the player scores by their *numeric* value, not by the string representation

//

function SortByPlayerScore(A, B: Pointer) : integer

begin

    Result := TPlayer(A).Score - TPlayer(B).Score;

end;



// ....



list.Sort(SortByPlayerScore);



grid.RowCount := list.Count + 1;

for i := 0 to list.Count - 1 do begin

    grid.Cells[0, i + 1] := list[i].Name;

    grid.Cells[1, i + 1] := IntToStr(list[i].Score);

end;