CxGrid使用小结(续)

激活内置编辑控件

1) <aView>.Controller.EditingController.ShowEdit(<aColumn>);
2) <aView>.Controller.EditingController.StartEditShowingTimer(<aColumn>);
3) <aView>.Controller.EditingItem := <aColumn>;
4) <aColumn>.Editing := True;

隐藏内置编辑控件
<aView>.Controller.EditingController.HideEdit(True);

===========================================================================

移除一个分组列

<aColumn>.GroupIndex := -1;
<aColumn>.Visible := True;

===========================================================================

保存修改到数据库

procedure <aForm>.FormClose(Sender: TObject; var Action: TCloseAction);
begin
if (<aGrid>.FocusedView <> nil) and (<aGrid>.FocusedView.DataController.EditState <> []) then
<aGrid>.FocusedView.DataController.Post;
end;

============================================================================

设置内置右键菜单

内置右键菜单包括二个菜单:cxGridStdHeaderMenu, TcxGridStdFooterMenu

uses cxGridStdPopupMenu;

procedure TForm1.cxGridPopupMenu1Popup(ASenderMenu: TComponent;
AHitTest: TcxCustomGridHitTest; X, Y: Integer; var AllowPopup: Boolean);
begin
if ASenderMenu is TcxGridStdHeaderMenu then
TcxGridStdHeaderMenu(ASenderMenu).OnPopup := StdHeaderMenuPopup;
end;

procedure TForm1.StdHeaderMenuPopup(Sender: TObject);
var
I: Integer;
begin
with TcxGridStdHeaderMenu(Sender).Items do
for I := 0 to Count - 1 do
if Items[I].Caption = 'Group By Box' then
begin
Items[I].Enabled := False;
System.Break;
end
end;

===========================================================================

得到选中记录的值

1) View.DataController.DataModeController.GridMode = False时

RecIdx := View.Controller.SelectedRecords[i].RecordIndex;
ColIdx := View.DataController.GetItemByFieldName(AFieldName).Index;
OutputVal := View.DataController.Values[RecIdx, ColIdx];

//RecID := View.DataController.GetRecordId(RecIdx);
//OutputVal := ADataSet.Lookup(View.DataController.KeyFieldNames, RecID, AFieldName);

2) View.DataController.DataModeController.GridMode = True时
Bkm := View.DataController.GetSelectedBookmark(ASelectedRecordIndex);
if ADataSet.BookmarkValid(TBookmark(Bkm)) then
begin
ADataSet.Bookmark := TBookmark(Bkm);
OutputVal := ADataSet.FieldByName(AFieldName).Value;
end;

View.BeginUpdate;
View.DataController.BeginLocate;
try
// make changes here…
finally
View.DataController.EndLocate;
View.EndUpdate;
end;

=============================================================

在GridMode禁用内置的右键Footer菜单

uses cxGridStdPopupMenu;

procedure cxGridPopupMenuOnPopup(...)
begin
if (ASenderMenu is TcxGridStdFooterMenu) and
<GridView>.DataController.DataModeController.GridMode then
AllowPopup := False;
end;

==============================================================

主从表任何时候只能展开一个组

procedure TForm1.ADetailDataControllerCollapsing(
ADataController: TcxCustomDataController; ARecordIndex: Integer;
var AAllow: Boolean);
var
I: Integer;
C: Integer;
begin
AAllow := False;
C := 0;
for I := 0 to ADataController.RecordCount - 1 do
begin
if ADataController.GetDetailExpanding(I) then
Inc(C);
if C > 1 then
AAllow := True;
end;
end;

procedure TForm1.ADetailDataControllerExpanding(
ADataController: TcxCustomDataController; ARecordIndex: Integer;
var AAllow: Boolean);
begin
ADataController.CollapseDetails;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
cxGrid1DBTableView1.DataController.OnDetailExpanding := ADetailDataControllerExpanding;
cxGrid1DBTableView1.DataController.OnDetailCollapsing := ADetailDataControllerCollapsing;
end;

=================================================================

动态创建层次(Level)和视图(View)

var
Grid: TcxGrid;
Level: TcxGridLevel;
View: TcxGridDBTableView;
begin
// Creates a Grid instance
Grid := TcxGrid.Create(SomeOwner);
Grid.Parent := SomeParent;
// Creates a Level
Level := Grid.Levels.Add;
Level.Name := 'SomeLevelName';
// Creates a View
View := Grid.CreateView(TcxGridDBTableView) as TcxGridDBTableView;
View.Name := 'SomeViewName';
// … and binds it to the Level
Level.GridView := View;
// Hooks up the View to the data
View.DataController.DataSource := SomeDataSource;
// … and creates all columns
View.DataController.CreateAllItems;
end;



此楼回复Re：
--------------------------------------------------------------------------------

======================================================================

获得Group Footer合计行对应的记录

procedure TForm1.cxGrid1DBTableView1CustomDrawFooterCell(
Sender: TcxGridTableView; ACanvas: TcxCanvas;
AViewInfo: TcxGridColumnHeaderViewInfo; var ADone: Boolean);
var
ALevel, ADataGroupIndex: Integer;
AGridRecord, AGroupRecord: TcxCustomGridRecord;
begin
if AViewInfo is TcxGridRowFooterCellViewInfo and // Row footer
(TcxGridDBColumn(AViewInfo.Column).DataBinding.FieldName = 'Area') then // Area column
begin
AGridRecord := TcxGridRowFooterCellViewInfo(AViewInfo).GridRecord;
ALevel := TcxGridRowFooterCellViewInfo(AViewInfo).Container.GroupLevel;
ADataGroupIndex := Sender.DataController.Groups.DataGroupIndexByRowIndex[AGridRecord.Index];
if ADataGroupIndex <> -1 then
begin
AGroupRecord := AGridRecord;
while AGroupRecord.Level <> ALevel do
AGroupRecord := AGroupRecord.ParentRecord;
AViewInfo.Text := AGroupRecord.DisplayTexts[0];
end;
end;
end;

===========================================================================

访问过滤之后的记录

var
I: Integer;
begin
Memo1.Lines.Clear;
with cxGrid1DBTableView1.DataController do
for I := 0 to FilteredRecordCount - 1 do
Memo1.Lines.Add(DisplayTexts[FilteredRecordIndex[I], 0]);
end;

============================================================================

获得单元的Font

cxGrid1DBTableView1.ViewInfo.RecordsViewInfo.Items[1].GetCellViewInfoByItem(
cxGrid1DBTableView1Company).EditViewInfo.Font;

============================================================================

根据Level名称找到Level对象

function GetLevelByName(AGrid: TcxGrid; ALevelName: string): TcxGridLevel;

function LoopThroughLevels(ALevel: TcxGridLevel; ALevelName: string): TcxGridLevel;
var
I: Integer;
begin
Result := nil;
for I := 0 to ALevel.Count - 1 do
begin
if ALevel[I].Name = ALevelName then
begin
Result := ALevel[I];
Exit;
end;
if ALevel[I].Count > 0 then
begin
Result := LoopThroughLevels(ALevel[I], ALevelName);
if Result <> nil then
Exit;
end;
end;
end;

var
I: Integer;
begin
Result := nil;
for I := 0 to AGrid.Levels.Count - 1 do
begin
if AGrid.Levels[I].Name = ALevelName then
begin
Result := AGrid.Levels[I];
Exit;
end;
if AGrid.Levels[I].Count > 0 then
begin
Result := LoopThroughLevels(AGrid.Levels[I], ALevelName);
if Result <> nil then
Exit;
end;
end;
end;

============================================================================

指定Filter Builder打开/保存过滤文件的默认路径

uses
..., cxFilterControlDialog;

procedure TForm.GridView1FilterControlDialogShow(
Sender: TObject);
begin
TfmFilterControlDialog(Sender).OpenDialog.InitialDir := 'D:/'
end;

============================================================================

保存/恢复带汇总行的布局

<TableView>.StoreToIniFile('c:/Grid.ini', True, [gsoUseSummary]);
<GridView>.RestoreFromIniFile(<inifilename>,True,False {or True, optional},[gsoUseSummary]);

============================================================================

取消过滤时移到第一行

uses
cxCustomData;

procedure TYour_Form.AViewDataControllerFilterChanged(Sender: TObject);
var
Filter: TcxDataFilterCriteria;
begin
with Sender as TcxDataFilterCriteria do
if IsEmpty then
DataController.FocusedRowIndex := 0;
end;

=============================================================================

排序后移到第一行

可以设置DataController.Options.FocusTopRowAfterSorting := True，也可以使用如下的代码：

uses
cxCustomData;

procedure TYour_Form.Your_ViewDataControllerSortingChanged(Sender: TObject);
begin
TcxCustomDataController(Sender).FocusedRowIndex := 0;
end;

==============================================================================

判断当前行是否第一行或最后一行

可以使用DataController的IsBOF, IsEOF方法，或者：
<AView>.Controller.Controller.FocusedRow.IsFirst
<AView>.Controller.Controller.FocusedRow.IsLast

==============================================================================

根据指定值查找记录

DataController提供了好几个方法来得到指定值对应的RecordIndex
对于Bound View可以使用FindRecordIndexByKeyValue方法

===============================================================================

编辑和显示Blob字段

该字段的Properties设置为BlobEdit，并将BlobPaintStyle 属性设为 bpsText

===============================================================================

得到可见行数

<View>.ViewInfo.VisibleRecordCount

===============================================================================

保存后的行设置为当前行

const
CM_SETFOCUSEDRECORD = WM_USER + 1002;

type
TForm1 = class(TForm)
cxGrid1DBTableView1: TcxGridDBTableView;
cxGrid1Level1: TcxGridLevel;
cxGrid1: TcxGrid;
dxMemData1: TdxMemData;
dxMemData1Field1: TStringField;
dxMemData1Field2: TIntegerField;
DataSource1: TDataSource;
cxGrid1DBTableView1RecId: TcxGridDBColumn;
cxGrid1DBTableView1Field1: TcxGridDBColumn;
cxGrid1DBTableView1Field2: TcxGridDBColumn;
Timer1: TTimer;
CheckBox1: TCheckBox;
procedure Timer1Timer(Sender: TObject);
procedure dxMemData1AfterPost(DataSet: TDataSet);
procedure CheckBox1Click(Sender: TObject);
private
procedure CMSetFocusedRecord(var Msg: TMessage); message CM_SETFOCUSEDRECORD;
public
{ Public declarations }
end;

var
Form1: TForm1;
FocusedIdx: Integer;


implementation

{$R *.dfm}

procedure TForm1.Timer1Timer(Sender: TObject);
begin
dxMemData1.AppendRecord(['', IntToStr(Random(1000)), Random(1000)]);
end;

procedure TForm1.dxMemData1AfterPost(DataSet: TDataSet);
begin
PostMessage(Handle, CM_SETFOCUSEDRECORD, Integer(cxGrid1DBTableView1), MakeLParam(cxGrid1DBTableView1.Controller.FocusedRowIndex, cxGrid1DBTableView1.Controller.TopRowIndex));
end;

procedure TForm1.CMSetFocusedRecord(var Msg: TMessage);
begin
TcxGridDBTableView(msg.WParam).Controller.FocusedRowIndex := Msg.LParamLo;
TcxGridDBTableView(msg.WParam).Controller.TopRowIndex := Msg.LParamHi;
end;

procedure TForm1.CheckBox1Click(Sender: TObject);
begin
Timer1.Enabled := TCheckBox(Sender).Checked;
end;

end.

=================================================================================

删除记录并获得焦点

procedure TForm1.BtnDeleteClick(Sender: TObject);
var
FocusedRow, TopRow: Integer;
View: TcxGridTableView;
DataController: TcxGridDataController;
begin
View := cxGrid1.FocusedView as TcxGridTableView;
DataController := View.DataController;

// Remember the top row (the vertical scrollbar position)
TopRow := View.Controller.TopRowIndex;
// Remember the focused row(!) index
FocusedRow := DataController.FocusedRowIndex;

DataController.DeleteFocused;

// After deletion the same row must be focused,
// although it will correspond to a different data record
DataController.FocusedRowIndex := FocusedRow;
// Restore the top row
View.Controller.TopRowIndex := TopRow;
end;

//=======================================================================================
数据库中的财务表为：
ID 收支类型 金额 其它属性

其中收支类型只有两种值：0 表示收入，1 表示支出 ；金额都是正数。

设置cxGrid的Footer 可以使得在显示时，列表的下方出现汇总行：“金额”的和
同样设置Default For Groups可以使得在用户拖动表头属性实现分组时，显示组内的汇总行：“金额”的和。

上面说的，用过cxGrid应该都会，下面就有这么一个问题

如果我想使汇总行的值变为如下的值应该怎样实现：
收支类型为0的金额的和 - 收支类型为1的金额的和
实现Footer的功能好办，因为它的值不会变，自己用循环写一个就完了，但是Default For Groups的功能就不好说了，因为它的值是根据用户拖动的属性计算的，而且还有可能是多层分组，想不出来了，所有到这来问
是不是要设置什么属性？或者cxGrid根本就没这个功能，那该用什么方法解决？希望哪位帮我解决，谢谢了先！

给你一个例子,可能对你有帮助,
with tvOrders.DataController.Summary do

begin
BeginUpdate;
try
SummaryGroups.Clear;
//The first summary group
with SummaryGroups.Add do
begin
//Add proposed grouping column(s)
TcxGridTableSummaryGroupItemLink(Links.Add).Column := tvOrdersCustomerID;
//Add summary items
with SummaryItems.Add as TcxGridDBTableSummaryItem do
begin
Column := tvOrdersPaymentAmount;
Kind := skSum;
Format := 'Amount Paid: $,0';
end;

with SummaryItems.Add as TcxGridDBTableSummaryItem do
begin
Column := tvOrdersPaymentAmount;
Kind := skCount;
Format := 'Records: 0';
end;

end;

//The second summary group
with SummaryGroups.Add do
begin
//Add proposed grouping column(s)
TcxGridTableSummaryGroupItemLink(Links.Add).Column := tvOrdersProductID;
//Add summary items
with SummaryItems.Add as TcxGridDBTableSummaryItem do
begin
Column := tvOrdersQuantity;
Kind := skSum;
Position := spFooter;
Format := 'TOTAL = 0';
end;

with SummaryItems.Add as TcxGridDBTableSummaryItem do
begin
Column := tvOrdersPurchaseDate;
Kind := skMin;
Position := spFooter;
end;
end;

finally
EndUpdate;
end;
end;

2007-7-19 12:56:41 go on

订单号 商品名 单价 数量 金额
001 aa 11.00 2 22.00
001 bb 2.00 2 4.00
001 cc 3.00 3 9.00

----------------------合计 7 35.00

002 ee 11.00 2 22.00
002 bb 3.00 2 6.00
002 cc 3.00 3 9.00

----------------------合计 7 37.00


总计14 72.00

每个单号分一个小结，能实现吗？

最后在底下实现总的合计




回复人：dctony() ( ) 信誉：100 2007-1-12 21:48:23 得分:100


?
可以的，cxGrid的功能比你想象的还要强大。
1.你先放一个cxGrid，设置好View，设置View.DataController连接的DataSource
2.激活DataSource连接的DataSet，双击cxGrid，点击Retrieve Fields，取得所有的Column
3.设置View的OptionsView.Footer=True，OptionsView.GroupFooters=True，这是为了把分组小计和总计面板显示出来
4.将“订单号”字段拖到cxGrid上方的分组面板(GroupbyBox)，将数据按“订单号”分组。这时你会发现单身所有的数据都缩起来了，如果想使所有的数据都展开，可以设置View.DataController.Options.dcoGroupsAlwaysExpanded=True
5.设置分组小计：把View.DataController.Summary.DefaultGroupSummaryItems点开，新增一个Item，Column属性在下拉里选择“数量”字段，FieldName属性为空，Format属性可以设置数值的显示格式，Kind属性下拉skSum加总，Position属性一定要选择spFooter。
6.设置总计：把View.DataController.Summary.FooterSummaryItems点开，新增一个Item，Column属性在下拉里选择“数量”字段，FieldName属性为空，Format属性可以设置数值的显示格式，Kind属性下拉skSum加总，Position属性一定要选择spFooter。
大功告成，按F9看一下胜利果实吧。

再奉送一个技巧，在Form1再放一个TcxGridPopupMenu控件，就在cxGrid控件旁边的那个，把TcxGridPopupMenu的Grid属性设置成你的cxGrid。
然后运行程序，在运行状态，点击Grid上的所有地方，左键或右键，你都会有意外收获。

ExpressQuantumGrid控件实在是太复杂，太庞大，最好的了解它的方法就是查帮助。