Author: Mike Shkolnik

How can I delete the row in TStringGrid component?

Answer:

If you worked with TStringGrid component, then you saw that in this component the 
Borland developers not provided the method for row deleting. 
In this tip I describe the few ways for it: 

1. navigate by rows and copy the row contains to the prev row: 
1   
2   procedure DeleteRow(yourStringGrid: TStringGrid; ARow: Integer);
3   var
4     i, j: Integer;
5   begin
6     with yourStringGrid do
7     begin
8       for i := ARow to RowCount - 2 do
9         for j := 0 to ColCount - 1 do
10          Cells[j, i] := Cells[j, i + 1];
11      RowCount := RowCount - 1
12    end;
13  end;


2. the modificated #1: 
14  
15  procedure DeleteRow(yourStringGrid: TStringGrid; ARow: Integer);
16  var
17    i: Integer;
18  begin
19    with yourStringGrid do
20    begin
21      for i := ARow to RowCount - 2 do
22        Rows[i].Assign(Rows[i + 1]);
23      RowCount := RowCount - 1
24    end;
25  end;


3. the "hacked" way. The TCustomGrid type (the TStringGrid is TCustomGrid's 
successor) have the DeleteRow method. But this method allocated not in public 
section but in protected section. So the all successors can "see" this DeleteRow 
method. 

26  type
27    THackStringGrid = class(TStringGrid);
28  
29  procedure DeleteRow(yourStringGrid: TStringGrid; ARow: Integer);
30  begin
31    with THackStringGrid(yourStringGrid) do
32      DeleteRow(ARow);
33  end;


Personally I use the third method but the first and second are more visual.

Also you should clear the Row after moving the data to the row above.  If not you 
will get the old date back when you add a Row. 

34  if StringGrid.RowCount > 2 then
35  begin
36    if StringGrid.Selection.Top <> (StringGrid.RowCount - 1) then
37    begin
38      for iRow := StringGrid.Selection.Top to (StringGrid.RowCount - 2) do
39      begin
40        for iCol := 0 to (StringGrid.ColCount - 1) do
41        begin
42          StringGrid.Cells[iCol, iRow] := StringGrid.Cells[iCol, iRow + 1];
43        end;
44      end;
45    end;
46    StringGrid.Rows[StringGrid.RowCount - 1].Clear;
47    StringGrid.RowCount := StringGrid.RowCount - 1;