else
      Result := DefaultColWidth;
  end;
end;

procedure TColumn.FontChanged;
begin
  Include(FAssignedValues, cvFont);
  Title.RefreshDefaultFont;
  Changed(False);
end;

function TColumn.GetAlignment: TAlignment;
begin
  if cvAlignment in FAssignedValues then
    Result := FAlignment
  else
    Result := DefaultAlignment;
end;

function TColumn.GetColor: TColor;
begin
  if cvColor in FAssignedValues then
    Result := FColor
  else
    Result := DefaultColor;
end;

function TColumn.GetExpanded: Boolean;
begin
  Result := FExpanded and Expandable;
end;

function TColumn.GetField: TField;
var
  Grid              : TCustomASDBGrid;
begin { Returns Nil if FieldName can't be found in dataset }
  Grid := GetGrid;
  if (FField = nil) and (Length(FFieldName) > 0) and Assigned(Grid) and
    Assigned(Grid.DataLink.DataSet) then
    with Grid.Datalink.Dataset do
      if Active or (not DefaultFields) then
        SetField(FindField(FieldName));
  Result := FField;
end;

function TColumn.GetFont: TFont;
var
  Save              : TNotifyEvent;
begin
  if not (cvFont in FAssignedValues) and (FFont.Handle <> DefaultFont.Handle)
    then
  begin
    Save := FFont.OnChange;
    FFont.OnChange := nil;
    FFont.Assign(DefaultFont);
    FFont.OnChange := Save;
  end;
  Result := FFont;
end;

function TColumn.GetGrid: TCustomASDBGrid;
begin
  if Assigned(Collection) and (Collection is TASDBGridColumns) then
    Result := TASDBGridColumns(Collection).Grid
  else
    Result := nil;
end;

function TColumn.GetDisplayName: string;
begin
  Result := FFieldName;
  if Result = '' then
    Result := inherited GetDisplayName;
end;

function TColumn.GetImeMode: TImeMode;
begin
  if cvImeMode in FAssignedValues then
    Result := FImeMode
  else
    Result := DefaultImeMode;
end;

function TColumn.GetImeName: TImeName;
begin
  if cvImeName in FAssignedValues then
    Result := FImeName
  else
    Result := DefaultImeName;
end;

function TColumn.GetParentColumn: TColumn;
var
  Col               : TColumn;
  Fld               : TField;
  I                 : Integer;
begin
  Result := nil;
  Fld := Field;
  if (Fld <> nil) and (Fld.ParentField <> nil) and (Collection <> nil) then
    for I := Index - 1 downto 0 do
    begin
      Col := TColumn(Collection.Items[I]);
      if Fld.ParentField = Col.Field then
      begin
        Result := Col;
        Exit;
      end;
    end;
end;

function TColumn.GetPickList: TStrings;
begin
  if FPickList = nil then
    FPickList := TStringList.Create;
  Result := FPickList;
end;

function TColumn.GetReadOnly: Boolean;
begin
  if cvReadOnly in FAssignedValues then
    Result := FReadOnly
  else
    Result := DefaultReadOnly;
end;

function TColumn.GetShowing: Boolean;
var
  Col               : TColumn;
begin
  Result := not Expanded and Visible;
  if Result then
  begin
    Col := Self;
    repeat
      Col := Col.ParentColumn;
    until (Col = nil) or not Col.Expanded;
    Result := Col = nil;
  end;
end;

function TColumn.GetVisible: Boolean;
var
  Col               : TColumn;
begin
  Result := FVisible;
  if Result then
  begin
    Col := ParentColumn;
    Result := Result and ((Col = nil) or Col.Visible);
  end;
end;

function TColumn.GetWidth: Integer;
begin
  if not Showing then
    Result := -1
  else
    if cvWidth in FAssignedValues then
      Result := FWidth
    else
      Result := DefaultWidth;
end;

function TColumn.IsAlignmentStored: Boolean;
begin
  Result := (cvAlignment in FAssignedValues) and (FAlignment <>
    DefaultAlignment);
end;

function TColumn.IsColorStored: Boolean;
begin
  Result := (cvColor in FAssignedValues) and (FColor <> DefaultColor);
end;

function TColumn.IsFontStored: Boolean;
begin
  Result := (cvFont in FAssignedValues);
end;

function TColumn.IsImeModeStored: Boolean;
begin
  Result := (cvImeMode in FAssignedValues) and (FImeMode <> DefaultImeMode);
end;

function TColumn.IsImeNameStored: Boolean;
begin
  Result := (cvImeName in FAssignedValues) and (FImeName <> DefaultImeName);
end;

function TColumn.IsReadOnlyStored: Boolean;
begin
  Result := (cvReadOnly in FAssignedValues) and (FReadOnly <> DefaultReadOnly);
end;

function TColumn.IsWidthStored: Boolean;
begin
  Result := (cvWidth in FAssignedValues) and (FWidth <> DefaultWidth);
end;

procedure TColumn.RefreshDefaultFont;
var
  Save              : TNotifyEvent;
begin
  if cvFont in FAssignedValues then
    Exit;
  Save := FFont.OnChange;
  FFont.OnChange := nil;
  try
    FFont.Assign(DefaultFont);
  finally
    FFont.OnChange := Save;
  end;
end;

procedure TColumn.RestoreDefaults;
var
  FontAssigned      : Boolean;
begin
  FontAssigned := cvFont in FAssignedValues;
  FTitle.RestoreDefaults;
  FAssignedValues := [];
  RefreshDefaultFont;
  FPickList.Free;
  FPickList := nil;
  ButtonStyle := cbsAuto;
  Changed(FontAssigned);
end;

procedure TColumn.SetAlignment(Value: TAlignment);
var
  Grid              : TCustomASDBGrid;
begin
  if IsStored then
  begin
    if (cvAlignment in FAssignedValues) and (Value = FAlignment) then
      Exit;
    FAlignment := Value;
    Include(FAssignedValues, cvAlignment);
    Changed(False);
  end
  else
  begin
    Grid := GetGrid;
    if Assigned(Grid) and (Grid.Datalink.Active) and Assigned(Field) then
      Field.Alignment := Value;
  end;
end;

procedure TColumn.SetButtonStyle(Value: TColumnButtonStyle);
begin
  if (Value = FButtonStyle) {or (FChineseCurrencyStyle)} then
    Exit;
  FButtonStyle := Value;
  Changed(False);
end;

procedure TColumn.SetColor(Value: TColor);
begin
  if (cvColor in FAssignedValues) and (Value = FColor) then
    Exit;
  FColor := Value;
  Include(FAssignedValues, cvColor);
  Changed(False);
end;

procedure TColumn.SetField(Value: TField);
begin
  if FField = Value then
    Exit;
  if Assigned(FField) and (GetGrid <> nil) then
    FField.RemoveFreeNotification(GetGrid);
  if Assigned(Value) and (csDestroying in Value.ComponentState) then
    Value := nil; // don't acquire references to fields being destroyed
  FField := Value;
  if Assigned(Value) then
  begin
    if GetGrid <> nil then
      FField.FreeNotification(GetGrid);
    FFieldName := Value.FullName;
  end;
  if not IsStored then
  begin
    if Value = nil then
      FFieldName := '';
    RestoreDefaults;
  end;
  Changed(False);
end;

procedure TColumn.SetFieldName(const Value: string);
var
  AField            : TField;
  Grid              : TCustomASDBGrid;
begin
  AField := nil;
  Grid := GetGrid;
  if Assigned(Grid) and Assigned(Grid.DataLink.DataSet) and
    not (csLoading in Grid.ComponentState) and (Length(Value) > 0) then
    AField := Grid.DataLink.DataSet.FindField(Value); { no exceptions }
  FFieldName := Value;
  SetField(AField);
  Changed(False);
end;

procedure TColumn.SetFont(Value: TFont);
begin
  FFont.Assign(Value);
  Include(FAssignedValues, cvFont);
  Changed(False);
end;

procedure TColumn.SetImeMode(Value: TImeMode);
begin
  if (cvImeMode in FAssignedValues) or (Value <> DefaultImeMode) then
  begin
    FImeMode := Value;
    Include(FAssignedValues, cvImeMode);
  end;
  Changed(False);
end;

procedure TColumn.SetImeName(Value: TImeName);
begin
  if (cvImeName in FAssignedValues) or (Value <> DefaultImeName) then
  begin
    FImeName := Value;
    Include(FAssignedValues, cvImeName);
  end;
  Changed(False);
end;

procedure TColumn.SetIndex(Value: Integer);
var
  Grid              : TCustomASDBGrid;
  Fld               : TField;
  I, OldIndex       : Integer;
  Col               : TColumn;
begin
  OldIndex := Index;
  Grid := GetGrid;

  if IsStored then
  begin
    Grid.BeginLayout;
    try
      I := OldIndex + 1;                // move child columns along with parent
      while (I < Collection.Count) and (TColumn(Collection.Items[I]).ParentColumn
        = Self) do
        Inc(I);
      Dec(I);
      if OldIndex > Value then          // column moving left
      begin
        while I > OldIndex do
        begin
          Collection.Items[I].Index := Value;
          Inc(OldIndex);
        end;
        inherited SetIndex(Value);
      end
      else
      begin
        inherited SetIndex(Value);
        while I > OldIndex do
        begin
          Collection.Items[OldIndex].Index := Value;
          Dec(I);
        end;
      end;
    finally
      Grid.EndLayout;
    end;
  end
  else
  begin
    if (Grid <> nil) and Grid.Datalink.Active then
    begin
      if Grid.AcquireLayoutLock then
      try
        Col := Grid.ColumnAtDepth(Grid.Columns[Value], Depth);
        if (Col <> nil) then
        begin
          Fld := Col.Field;
          if Assigned(Fld) then
            Field.Index := Fld.Index;
        end;
      finally
        Grid.EndLayout;
      end;
    end;
    inherited SetIndex(Value);
  end;
end;

procedure TColumn.SetPickList(Value: TStrings);
begin
  if Value = nil then
  begin
    FPickList.Free;
    FPickList := nil;
    Exit;
  end;
  PickList.Assign(Value);
end;

procedure TColumn.SetPopupMenu(Value: TPopupMenu);
begin
  FPopupMenu := Value;
  if Value <> nil then
    Value.FreeNotification(GetGrid);
end;

procedure TColumn.SetReadOnly(Value: Boolean);
var
  Grid              : TCustomASDBGrid;
begin
  if FRowNumber then
  begin
    ShowMessage('RowNumber屬性為真；行號字段不可編輯！');
    FReadonly := True;
    Exit;
  end;
  Grid := GetGrid;
  if not IsStored and Assigned(Grid) and Grid.Datalink.Active and Assigned(Field)
    then
    Field.ReadOnly := Value
  else
  begin
    if (cvReadOnly in FAssignedValues) and (Value = FReadOnly) then
      Exit;
    FReadOnly := Value;
    Include(FAssignedValues, cvReadOnly);
    Changed(False);
  end;
end;

procedure TColumn.SetTitle(Value: TColumnTitle);
begin
  FTitle.Assign(Value);
end;

procedure TColumn.SetWidth(Value: Integer);
var
  Grid              : TCustomASDBGrid;
  TM                : TTextMetric;
  DoSetWidth        : Boolean;
begin
  DoSetWidth := IsStored;
  if not DoSetWidth then
  begin
    Grid := GetGrid;
    if Assigned(Grid) then
    begin
      if Grid.HandleAllocated and Assigned(Field) and Grid.FUpdateFields then
        with Grid do
        begin
          Canvas.Font := Self.Font;
          GetTextMetrics(Canvas.Handle, TM);
          Field.DisplayWidth := (Value + (TM.tmAveCharWidth div 2) -
            TM.tmOverhang - 3)
            div TM.tmAveCharWidth;
        end;
      if (not Grid.FLayoutFromDataset) or (cvWidth in FAssignedValues) then
        DoSetWidth := True;
    end
    else
      DoSetWidth := True;
  end;