我在stringgrid中嵌套了一个ComboBox,是否与这个有关? procedure Tfrmsfjl.cbInplaceComboBoxChange(Sender: TObject); var intRow:integer; begin inherited; {Get the ComboBox selection and place in the grid} with cbInplaceComboBox do begin intRow := sgall.Row; if (sgall.Col = 2) then sgall.Cells[2, intRow] := Items[ItemIndex] else sgall.Cells[sgall.Col, intRow] := Items[ItemIndex]; Visible := False; end; sgall.SetFocus; try if not dm.ADO_conn.Connected then dm.ADO_conn.Open; try strsql:='select * from syn_sfxm where sfxm='''+sgall.Cells[0,introw]+''''; with dm.sfxm do begin close; SQL.Clear; sql.Add(strsql); open; end; sgall.cells[1,introw]:=dm.sfxm.FieldByName('sfxmbh').AsString; except showmessage('无法查找到相关信息!'); end; //dm.ADO_conn.Close; dm.sfxm.Close; except showmessage('无法与数据库连接!'); exit; end; end;
access voliation 是非法访问,
可能是网络有问题,也可能是内存泄露...
procedure Tfrmsfjl.cbInplaceComboBoxChange(Sender: TObject);
var
intRow:integer;
begin
inherited; {Get the ComboBox selection and place in the grid}
with cbInplaceComboBox do
begin
intRow := sgall.Row;
if (sgall.Col = 2) then
sgall.Cells[2, intRow] := Items[ItemIndex]
else
sgall.Cells[sgall.Col, intRow] := Items[ItemIndex];
Visible := False;
end;
sgall.SetFocus;
try
if not dm.ADO_conn.Connected then dm.ADO_conn.Open;
try
strsql:='select * from syn_sfxm where sfxm='''+sgall.Cells[0,introw]+'''';
with dm.sfxm do
begin
close;
SQL.Clear;
sql.Add(strsql);
open;
end;
sgall.cells[1,introw]:=dm.sfxm.FieldByName('sfxmbh').AsString;
except
showmessage('无法查找到相关信息!');
end;
//dm.ADO_conn.Close;
dm.sfxm.Close;
except
showmessage('无法与数据库连接!');
exit;
end;
end;
检查程序内部给stringgrid赋值时是否有读取了并不存在的数据项,例如越界读取
请仔细检查你的程序逻辑,看是否使用未初始化的指针、未实例化的对象,或使用了已经解除的指针或对象,或者解除了的全局对象未将其置为nil。
同样的操作在xp上有错但在win2000上没错,是由于win2000使用了更稳定和厚实的内存管理方法。
fscyber(无知无识) 的代码,是否有错
经过我多方查找,终找到一个比较好的例子,和大家一同分享:
=========================================================
StringGrid.dpr:
program StringGrid;uses
Forms,
frmMain in 'frmMain.pas' {Form1};{$R *.RES}begin
Application.Initialize;
Application.CreateForm(TForm1, Form1);
Application.Run;
end.
===================================================================
StringGrid.dpr
program StringGrid;uses
Forms,
frmMain in 'frmMain.pas' {Form1};{$R *.RES}begin
Application.Initialize;
Application.CreateForm(TForm1, Form1);
Application.Run;
end.
=========================================================================
frmMain.dfm
object Form1: TForm1
Left = 189
Top = 108
Width = 430
Height = 390
Caption = 'Example: TStringGrid advanced using'
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
OldCreateOrder = False
OnCreate = FormCreate
PixelsPerInch = 96
TextHeight = 13
object StringGrid1: TStringGrid
Left = 8
Top = 8
Width = 405
Height = 201
ColCount = 2
DefaultColWidth = 200
DefaultRowHeight = 21
RowCount = 9
TabOrder = 0
OnDrawCell = StringGrid1DrawCell
OnSelectCell = StringGrid1SelectCell
RowHeights = (
21
21
21
21
21
21
21
21
21)
end
object cbInplaceComboBox: TComboBox
Left = 216
Top = 32
Width = 145
Height = 21
Style = csDropDownList
ItemHeight = 13
TabOrder = 1
OnChange = cbInplaceComboBoxChange
Items.Strings = (
'1 value '
'2 value '
'3 value '
'4 value'
'5 value'
'6 value'
'7 value '
'8 value'
'9 value')
end
object Button1: TButton
Left = 320
Top = 333
Width = 91
Height = 25
Caption = '&Close'
Default = True
TabOrder = 2
OnClick = Button1Click
end
object MemoDescription: TMemo
Left = 7
Top = 216
Width = 406
Height = 105
Font.Charset = DEFAULT_CHARSET
Font.Color = clNavy
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = [fsBold]
Lines.Strings = (
'In this sample I shows how you can:'
''
'1. change the inplace editor for second column '
' from standard inplace editor to user TComboBox component'
''
' view the next procedures:'
' - TfrmMain.FormCreate'
' - TfrmMain.CMDialogKey'
' - TfrmMain.cbInplaceComboBoxChange'
' - TfrmMain.StringGrid1SelectCell'
''
'2. draw the cell values with different fonts'
''
' view the next procedure:'
' - TfrmMain.StringGrid1DrawCell'
' '
'3. change alignment for cells'
' '
' view the next procedure:'
' - TfrmMain.StringGrid1DrawCell')
ParentFont = False
ScrollBars = ssVertical
TabOrder = 3
end
end
========================================================================
frmMain.pas
unit frmMain;interfaceuses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, Grids;type
TForm1 = class(TForm)
StringGrid1: TStringGrid;
cbInplaceComboBox: TComboBox;
Button1: TButton;
MemoDescription: TMemo;
procedure FormCreate(Sender: TObject);
procedure cbInplaceComboBoxChange(Sender: TObject);
procedure StringGrid1SelectCell(Sender: TObject; ACol, ARow: Integer;
var CanSelect: Boolean);
procedure StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
Rect: TRect; State: TGridDrawState);
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
procedure CMDialogKey(var msg: TCMDialogKey); message CM_DIALOGKEY;
public
{ Public declarations }
end;var
Form1: TForm1;implementation{$R *.DFM}procedure TForm1.FormCreate(Sender: TObject);
var
i:integer;
begin
StringGrid1.DefaultRowHeight:=cbInplaceComboBox.Height;
cbInplaceComboBox.Visible:=False;
StringGrid1.Cells[0,0]:='Row No';
StringGrid1.Cells[1,0]:='Values(from combobox)';
for i:=1 to StringGrid1.RowCount-1 do
StringGrid1.Cells[0,i]:=IntToStr(i);
end;procedure TForm1.CMDialogKey(var msg:TCMDialogKey);
begin
if (ActiveControl = cbInplaceComboBox) then
begin
if (msg.CharCode = VK_TAB) then
begin
//set focus back to the grid and pass the tab key to it
cbInplaceComboBox.SetFocus;
cbInplaceComboBox.Perform(WM_KEYDOWN, msg.CharCode, msg.KeyData);
// swallow this message
msg.result := 1;
Exit;
end;
end; inherited;
end;procedure TForm1.cbInplaceComboBoxChange(Sender: TObject);
var
intRow:integer;
begin
inherited; {Get the ComboBox selection and place in the grid}
with cbInplaceComboBox do
begin
intRow := StringGrid1.Row;
if (StringGrid1.Col = 2) then
StringGrid1.Cells[2, intRow] := Items[ItemIndex]
else
StringGrid1.Cells[StringGrid1.Col, intRow] := Items[ItemIndex];
Visible := False;
end;
StringGrid1.SetFocus;
end;procedure TForm1.StringGrid1SelectCell(Sender: TObject; ACol,
ARow: Integer; var CanSelect: Boolean);
var
R:TRect;
begin
if ((ACol = 1) and (ARow <> 0)) then
begin
{Size and position the combo box to fit the cell}
R := StringGrid1.CellRect(ACol, ARow);
R.Left := R.Left + StringGrid1.Left;
R.Right := R.Right + StringGrid1.Left;
R.Top := R.Top + StringGrid1.Top;
R.Bottom := R.Bottom + StringGrid1.Top; {Show the combobox}
with cbInplaceComboBox do
begin
Left := R.Left + 1;
Top := R.Top + 1;
Width := (R.Right + 1) - R.Left;
Height := (R.Bottom + 1) - R.Top;
ItemIndex := Items.IndexOf(StringGrid1.Cells[ACol, ARow]);
Visible := True;
SetFocus;
end;
end;
CanSelect := True;end;procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
Rect: TRect; State: TGridDrawState);
const
AlignFlags: array [TAlignment] of Integer =
(DT_LEFT or DT_VCENTER or DT_WORDBREAK or DT_EXPANDTABS or DT_NOPREFIX,
DT_RIGHT or DT_VCENTER or DT_WORDBREAK or DT_EXPANDTABS or DT_NOPREFIX,
DT_CENTER or DT_VCENTER or DT_WORDBREAK or DT_EXPANDTABS or DT_NOPREFIX);
var s: string;
begin
inherited; with Rect do
begin
Left := Left + 2;
Top := Top + 2;
Right := Right - 5
end; s:= StringGrid1.Cells[ACol, ARow]; if (ARow = 0) and (ACol < StringGrid1.ColCount) then
begin
StringGrid1.Canvas.Font.Style := StringGrid1.Canvas.Font.Style + [fsBold];
StringGrid1.Canvas.Brush.Color := StringGrid1.FixedColor;
StringGrid1.Canvas.FillRect(Rect); DrawText(StringGrid1.Canvas.Handle,
PChar(s), Length(s),
Rect, AlignFlags[taCenter]);
end
else
if (ACol = 0) and (ARow > 0) and (ARow < StringGrid1.RowCount) then
begin
StringGrid1.Canvas.FillRect(Rect);
DrawText(StringGrid1.Canvas.Handle,
PChar(s), Length(s),
Rect, AlignFlags[taRightJustify]);
end;
end;procedure TForm1.Button1Click(Sender: TObject);
begin
close;
end;end.