DevExpress部分使用技巧

KeyLife富翁笔记

作者 : 轻舞肥羊

标题 : DevExpress部分使用技巧(原创)

关键字: DevExpress,cxGrid

分类 : 开发技巧

密级 : 公开

(评分:★★★★ , 回复: 6, 阅读: 5204) »»

本文由轻舞肥羊发表于大富翁论坛

转载请标明出处,谢谢

声明:以下代码请看懂再使用,本人水平有限,发现bug希望提出,让我们共同改进

2004-1-10 17:06:00

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2004-1-10 17:08:06 1.扩展cxLookupComboBox,使其支持多列查询的cxLookupComboBoxEx//====================== ========================================================

// Unit Name: cxLookupComboBoxEx

// Author : ysai

// Date : 2003

// Purpose : 扩展cxLookupComboBox,cxDBLookupComboBox,使其支持多列过滤

// History :

// 2003-05-28大数据量改进

// 2003-07-07可操作性改进

// 2003-08-20效率改进

// 2003-08-29加入过滤延时

// 注意:

// 限制1,不能再使用Properties.OnChange事件

// 限制2,不能再使用Properties.ListSource.DataSet.OnFilterRecord事件

// 限制3,不能再使用Properties.ListSource.DataSet.Filtered属性

// 其它,最好在设计期设好一切属性,运行期再设置属性可能引发求知错误

//==============================================================================

unit cxLookupComboBoxEx;

interface

uses

SysUtils, Classes, Controls, Windows, Messages,DB,StrUtils,

cxControls, cxContainer, cxEdit, cxTextEdit,

cxMaskEdit, cxDropDownEdit, cxLookupEdit, cxDBLookupEdit,

cxDBLookupComboBox;

type

TcxLookupComboBoxEx = class(TcxLookupComboBox)

private

//保存要过滤的字段列表

FFieldList : TList;

FFindText : String;

//过滤事件

procedure _OnFilterRecord(DataSet: TDataSet; var Accept: Boolean);

//编辑框文字改变事件

procedure _OnChange(Sender : TObject);

procedure GetFieldList;

//延时过滤消息

procedure WMTimer (var Message: TMessage); message WM_TIMER;

protected

//下拉表格收回时

procedure CloseUp(AAccept: Boolean); override;

//过滤过程

procedure _FilterListSource;

//初始化下拉表格事件

procedure DoInitPopup; override;

public

constructor Create(AOwner : TComponent); override;

destructor Destroy; override;

//更新要过滤的字段列表

procedure UpdateFilterFields;

published

end;

TcxDBLookupComboBoxEx = class(TcxDBLookupComboBox)

private

//保存要过滤的字段列表

FFieldList : TList;

FFindText : String;

//过滤事件

procedure _OnFilterRecord(DataSet: TDataSet; var Accept: Boolean);

//编辑框文字改变事件

procedure _OnChange(Sender : TObject);

//取得要过滤的字段列表

procedure GetFieldList;

//延时过滤消息

procedure WMTimer (var Message: TMessage); message WM_TIMER;

protected

//下拉表格收回时

procedure CloseUp(AAccept: Boolean); override;

//过滤过程

procedure _FilterListSource;

//初始化下拉表格事件

procedure DoInitPopup; override;

public

constructor Create(AOwner : TComponent); override;

destructor Destroy; override;

//更新要过滤的字段列表

procedure UpdateFilterFields;

published

end;

procedure Register;

implementation

const

UM_TIMER_FILTER = WM_USER + $101; //自定义延时消息ID

FILTERTIMER = 500; //延时时间

DROPDOWN_ROWS = 12;

procedure Register;

begin

RegisterComponents('Dev Express', [TcxLookupComboBoxEx,TcxDBLookupComboBoxEx]);

end;

{ TcxLookupComboBoxEx }

procedure TcxLookupComboBoxEx.CloseUp(AAccept: Boolean);

begin

inherited;

//收起下拉后取消过滤

if Assigned(Properties.ListSource) then

if Assigned(Properties.ListSource.DataSet) then

Properties.ListSource.DataSet.Filtered := False;

end;

constructor TcxLookupComboBoxEx.Create(AOwner: TComponent);

begin

inherited;

//默认值

Properties.AutoSelect := False;

Properties.DropDownAutoSize := True;

Properties.DropDownListStyle := lsEditList;

Properties.DropDownRows := DROPDOWN_ROWS;

Properties.DropDownSizeable := True;

Properties.IncrementalFiltering := False;

Properties.Revertable := True;

Properties.OnChange := _OnChange;

Properties.UseLeftAlignmentOnEditing := False;

end;

destructor TcxLookupComboBoxEx.Destroy;

begin

//释放过滤字段列表

if Assigned(FFieldList) then FFieldList.Free;

inherited;

end;

procedure TcxLookupComboBoxEx.DoInitPopup;

begin

//取得过滤字段

if Assigned(Properties.ListSource) then

if Assigned(Properties.ListSource.DataSet) then

begin

GetFieldList;

Properties.ListSource.DataSet.Filtered := False;

end;

inherited DoInitPopup;

end;

procedure TcxLookupComboBoxEx._FilterListSource;

//过滤字段

begin

if Assigned(Properties.ListSource)

and Assigned(Properties.ListSource.DataSet) then

try

Properties.ListSource.DataSet.DisableControls;

Properties.ListSource.DataSet.Filtered := False;

Properties.ListSource.DataSet.OnFilterRecord := _OnFilterRecord;

if Text <> '' then

begin

FFindText := Text;

if SelLength > 0 then

FFindText := LeftStr(Text,SelStart);

Properties.ListSource.DataSet.Filtered := FFindText <> '';

end;

Changed;

finally

Properties.ListSource.DataSet.EnableControls;

end;

procedure TcxLookupComboBoxEx.GetFieldList;

//取得过滤字段列表

var

i : Integer;

sFieldName : String;

fdTemp : TField;

begin

if not Assigned(FFieldList) then

begin

FFieldList := TList.Create;

for i:=0 to Properties.ListColumns.Count -1 do

begin

sFieldName := Properties.ListColumns.Items[i].FieldName;

if sFieldName = '' then Continue;

fdTemp := Properties.ListSource.DataSet.FindField(sFieldName);

if Assigned(fdTemp) then

FFieldList.Add(Pointer(fdTemp));

end;

procedure TcxLookupComboBoxEx._OnChange(Sender: TObject);

//设置延时

begin

if Focused and DroppedDown then

begin

KillTimer(Handle,UM_TIMER_FILTER);

SetTimer(Handle,UM_TIMER_FILTER,FILTERTIMER,nil);

end;

procedure TcxLookupComboBoxEx._OnFilterRecord(DataSet: TDataSet;

var Accept: Boolean);

//过滤事件

var

s : String;

i : Integer;

begin

s := LowerCase(FFindText);

if (s <> '') and (Properties.ListColumns.Count > 0) then

begin

Accept := False;

for i := 0 to FFieldList.Count -1 do

begin

Accept := Pos(s,LowerCase(TField(FFieldList[i]).AsString))>0;

if Accept then Exit;

end;

end

else

Accept := True;

end;

procedure TcxLookupComboBoxEx.WMTimer(var Message: TMessage);

//延时更新消息

begin

KillTimer(Handle,UM_TIMER_FILTER);

if Focused and DroppedDown then _FilterListSource;

end;

procedure TcxLookupComboBoxEx.UpdateFilterFields;

//更新要过滤的字段列表

begin

if Assigned(FFieldList) then

begin

FFieldList.Free;

FFieldList := nil;

end;

GetFieldList;

end;

{ TcxDBLookupComboBoxEx }

procedure TcxDBLookupComboBoxEx.CloseUp(AAccept: Boolean);

begin

inherited;

//收起下拉后取消过滤

if Assigned(Properties.ListSource) then

if Assigned(Properties.ListSource.DataSet) then

Properties.ListSource.DataSet.Filtered := False;

end;

constructor TcxDBLookupComboBoxEx.Create(AOwner: TComponent);

begin

inherited;

//默认值

Properties.AutoSelect := False;

Properties.DropDownListStyle := lsEditList;

Properties.DropDownRows := DROPDOWN_ROWS;

Properties.DropDownSizeable := True;

Properties.IncrementalFiltering := False;

Properties.Revertable := True;

Properties.OnChange := _OnChange;

Properties.UseLeftAlignmentOnEditing := False;

end;

destructor TcxDBLookupComboBoxEx.Destroy;

begin

//释放过滤字段列表

if Assigned(FFieldList) then FFieldList.Free;

inherited;

end;

procedure TcxDBLookupComboBoxEx.DoInitPopup;

begin

//取得过滤字段

if Assigned(Properties.ListSource) then

if Assigned(Properties.ListSource.DataSet) then

begin

GetFieldList;

Properties.ListSource.DataSet.Filtered := False;

end;

inherited DoInitPopup;

end;

procedure TcxDBLookupComboBoxEx._FilterListSource;

//过滤字段

begin

if Assigned(Properties.ListSource)

and Assigned(Properties.ListSource.DataSet) then

try

Properties.ListSource.DataSet.DisableControls;

Properties.ListSource.DataSet.Filtered := False;

Properties.ListSource.DataSet.OnFilterRecord := _OnFilterRecord;

if Text <> '' then

begin

FFindText := Text;

if SelLength > 0 then

FFindText := LeftStr(Text,SelStart);

Properties.ListSource.DataSet.Filtered := FFindText <> '';

end;

Changed;

finally

Properties.ListSource.DataSet.EnableControls;

end;

procedure TcxDBLookupComboBoxEx.GetFieldList;

//取得过滤字段列表

var

i : Integer;

sFieldName : String;

fdTemp : TField;

begin

if not Assigned(FFieldList) then

begin

FFieldList := TList.Create;

for i:=0 to Properties.ListColumns.Count -1 do

begin

sFieldName := Properties.ListColumns.Items[i].FieldName;

if sFieldName = '' then Continue;

fdTemp := Properties.ListSource.DataSet.FindField(sFieldName);

if Assigned(fdTemp) then

FFieldList.Add(Pointer(fdTemp));

end;

procedure TcxDBLookupComboBoxEx._OnChange(Sender: TObject);

//设置延时

begin

if Focused and DroppedDown then

begin

KillTimer(Handle,UM_TIMER_FILTER);

SetTimer(Handle,UM_TIMER_FILTER,FILTERTIMER,nil);

end;

procedure TcxDBLookupComboBoxEx._OnFilterRecord(DataSet: TDataSet;

var Accept: Boolean);

//过滤事件

var

s : String;

i : Integer;

begin

s := LowerCase(FFindText);

if (s <> '') and (Properties.ListColumns.Count > 0) then

begin

Accept := False;

for i := 0 to FFieldList.Count -1 do

begin

Accept := Pos(s,LowerCase(TField(FFieldList[i]).AsString))>0;

if Accept then Exit;

end;

end

else

Accept := True;

end;

procedure TcxDBLookupComboBoxEx.WMTimer(var Message: TMessage);

//延时更新消息

begin

KillTimer(Handle,UM_TIMER_FILTER);

if Focused and DroppedDown then _FilterListSource;

end;

procedure TcxDBLookupComboBoxEx.UpdateFilterFields;

//更新要过滤的字段列表

begin

if Assigned(FFieldList) then

begin

FFieldList.Free;

FFieldList := nil;

end;

GetFieldList;

end;

end.

2004-1-10 17:14:06 2.动态生成TcxGridDBTableView的列及页脚的合计栏var

i : Integer;

cl : TcxGridDBColumn;

begin

Screen.Cursor := crHourGlass;

cxtvMaster.BeginUpdate;

try

cxtvMaster.ClearItems;

cxtvMaster.DataController.Summary.FooterSummaryItems.Clear;

for i := 0 to cxtvMaster.DataController.DataSet.FieldCount - 1 do

begin

cl := cxtvMaster.CreateColumn;

cl.DataBinding.FieldName :=

cxtvMaster.DataController.DataSet.Fields[i].FieldName;

if cxtvMaster.DataController.DataSet.Fields[i] is TNumericField then

begin

TNumericField(cxtvMaster.DataController.DataSet.Fields[i])

.DisplayFormat := '#,##0.00';

cl.Width := 80;

with TcxGridDBTableSummaryItem(

cxtvMaster.DataController.Summary.FooterSummaryItems.Add) do

begin

Column := cl;

FieldName := cl.DataBinding.FieldName;

Format := '#,##0.00';

Kind := skSum;

end;

end

else if cxtvMaster.DataController.DataSet.Fields[i] is TStringField then

cl.Width := 100

else

cl.Width := 80;

cl.HeaderAlignmentHorz := taCenter;

end; //if

finally

cxtvMaster.EndUpdate;

Screen.Cursor := crDefault;

end;

2004-1-10 17:24:32 3.动态生成TcxGridDBBandedTableView的列及页脚的合计栏如果存储过程或SQL返回如下结果集

员工 1月$ 1月￥ 2月$ 2月￥合计$ 合计￥

-------------------------------------------

测试员A 200 1658 300 2487 500 4145

将生成如下样式的Grid(页脚没有画出,麻烦,另外设置了显示格式,金额将以#,##0.00的方式显示)

_________________________________________________

| 员工 | 1月 | 2月 | 合计 |

|-----------------------------------------------|

| 员工 | ＄ | ￥ | ＄ | ￥ | ＄ | ￥ |

|-----------------------------------------------|

|测试员A | 200 | 1658 | 300 | 2487 | 500 | 4145 |

-------------------------------------------------

var

i : Integer;

cl : TcxGridDBBandedColumn;

begin

Screen.Cursor := crHourGlass;

cxbtvMaster.BeginUpdate;

try

cxbtvMaster.ClearItems;

cxbtvMaster.Bands.Clear;

cxbtvMaster.DataController.Summary.FooterSummaryItems.Clear;

for i := 0 to cxbtvMaster.DataController.DataSet.FieldCount - 1 do

begin

if i = 0 then

with cxbtvMaster.Bands.Add do

begin

Options.HoldOwnColumnsOnly := True;

Caption := cxbtvMaster.DataController.DataSet.Fields[i].FieldName;

end;

if RightStr(

cxbtvMaster.DataController.DataSet.Fields[i].FieldName,

1) = '$' then

with cxbtvMaster.Bands.Add do

begin

Options.HoldOwnColumnsOnly := True;

Caption := Copy(

cxbtvMaster.DataController.DataSet.Fields[i].FieldName, 1,

Length(cxbtvMaster.DataController.DataSet.Fields[i].FieldName)

- 1);

cxbtvMaster.DataController.DataSet.Fields[i].DisplayLabel := '＄';

end;

if RightStr(

cxbtvMaster.DataController.DataSet.Fields[i].FieldName,

1) = '￥' then

cxbtvMaster.DataController.DataSet.Fields[i].DisplayLabel := '￥';

cl := cxbtvMaster.CreateColumn;

cl.HeaderAlignmentHorz := taCenter;

cl.Position.BandIndex := cxbtvMaster.Bands.Count - 1;

cl.DataBinding.FieldName :=

cxbtvMaster.DataController.DataSet.Fields[i].FieldName;

if cxbtvMaster.DataController.DataSet.Fields[i] is TNumericField then

begin

TNumericField(cxbtvMaster.DataController.DataSet.Fields[i])

.DisplayFormat := '#,##0.00';

cl.Width := 80;

with TcxGridDBBandedTableSummaryItem(

cxbtvMaster.DataController.Summary.FooterSummaryItems.Add) do

begin

Column := cl;

FieldName := cl.DataBinding.FieldName;

Format := '#,##0.00';

Kind := skSum;

end;

end

else if cxbtvMaster.DataController.DataSet.Fields[i] is TStringField then

cl.Width := 100

else

cl.Width := 80;

end; //if

finally

cxbtvMaster.EndUpdate;

Screen.Cursor := crDefault;

end;

2004-1-31 22:36:25 4.自动调整列宽的方法要注意的地方可以用ApplyBestFit实现自动列宽;

不能在BeginUpdate和EndUpdate之间调用这个方法,否则会产生下标越界错误;

在BeginUpdate和EndUpdate中清除/建立列不会产生屏幕闪烁,其它需要长时间更新cxGrid数据的操作最好放在BeginUpdate和EndUpdate执行,并用try包起来.

2004-2-8 15:32:30 DevExpress Bar的动态菜单没有什么说明,细心点应该知道表结构及数据的内容形式

对比了一下代码,用dxBar比用ToolBar+PopupMenu生成动态菜单要简单,只用了一个递归过程

type

//菜单项

PMenuItemInfo = ^TMenuItemInfo;

TMenuItemInfo = record

ID : string;

ParentID : string;

Caption : string;

Hint : string;

LibraryName : string;

ProcedureName : string;

wParam : Integer;

lParam : Integer;

end;

procedure TmgMainForm.BuildMenu;

//生成菜单

procedure SetMenuItemInfo(

const ADataSet : TDataSet;

const AItem : PMenuItemInfo

);

begin

AItem.ID := ADataSet.FieldByName('ID').AsString;

AItem.ParentID := ADataSet.FieldByName('ParentID').AsString;

AItem.Caption := ADataSet.FieldByName('Caption').AsString;

AItem.Hint := ADataSet.FieldByName('Hint').AsString;

AItem.LibraryName := ADataSet.FieldByName('LibraryName').AsString;

AItem.ProcedureName := ADataSet.FieldByName('ProcedureName').AsString;

AItem.wParam := ADataSet.FieldByName('wParam').AsInteger;

AItem.lParam := ADataSet.FieldByName('lParam').AsInteger;

end;

procedure CreateItemList(

const ADataSet : TDataSet;

const AList : TList;

const AText : string

);

//根据父节点建立子项目列表

var

m : PMenuItemInfo;

i : Integer;

begin

ADataSet.First;

for i := 0 to ADataSet.RecordCount - 1 do

begin

if ADataSet.FieldByName('ParentID').AsString = AText then

begin

New(m);

SetMenuItemInfo(ADataSet,m);

AList.Add(m);

ADataSet.Delete;

end else

ADataSet.Next;

end; //for

end;

procedure CreateMenuItems(

const ADataSet : TDataSet;

const AKeyValue : string;

const AItemLinks : TdxBarItemLinks;

const AIndex : Integer

);

//建立菜单项

var

db : TdxBarButton;

dbs : TdxBarSubItem;

l : TList;

i : Integer;

j : Integer;

bg : Boolean;

begin

bg := False;

j := AIndex;

l := TList.Create;

try

CreateItemList(ADataSet, l, AKeyValue);

for i := 0 to l.Count - 1 do

begin

if ADataSet.Locate('ParentID', PMenuItemInfo(l[i]).ID, []) then

begin

//有子项

dbs := TdxBarSubItem.Create(dxBar);

dbs.Caption := PMenuItemInfo(l[i]).Caption;

dbs.Hint := PMenuItemInfo(l[i]).Hint;

dbs.Tag := Integer(l[i]);

if AIndex > 0 then

dbs.ImageIndex := 0;

with AItemLinks.Add do

begin

Item := dbs;

Index := j;

BeginGroup := bg;

end; //with

bg := False;

CreateMenuItems(ADataSet, PMenuItemInfo(l[i]).ID, dbs.ItemLinks, 0);

if dbs.ItemLinks.Count = 0 then

dbs.Free

else

Inc(j);

end

else begin

//无子项

if not (PMenuItemInfo(l[i]).Caption = '-') then

begin

db := TdxBarButton.Create(dxBar);

db.Caption := PMenuItemInfo(l[i]).Caption;

db.Hint := PMenuItemInfo(l[i]).Hint;

db.Tag := Integer(l[i]);

db.OnClick := MenuItemClick;

if AIndex > 0 then

db.ImageIndex := 0;

with AItemLinks.Add do

begin

Item := db;

Index := j;

BeginGroup := bg;

end;

bg := False;

Inc(j);

end

else begin

bg := True;

end; //if bg

end; //if Locate

end; //for

finally

l.Free;

end;

var

rsMenus : TDataSet;

begin

rsMenus := mgDMMain.GetMenus; //取得数据集

if Assigned(rsMenus) then

try

CreateMenuItems(rsMenus, '', dxBar.Bars[0].ItemLinks, 1);

//一定要刷新一下,否则不更改样式会出错

dxBar.Bars[0].ItemLinks[0].Visible := False;

dxBar.Bars[0].ItemLinks[0].Visible := True;

finally

rsMenus.Free;

end;

2005-1-4 16:34:35 取得TcxLookupComboBox下拉列表中各项的内容Properties.DataController.Values包含了所有内容,如果要取得当前选择行的内容,用以下代码

//cmb:TcxLookupComboBox;

with cmb.Properties.DataController do

ShowMessage(Values[FindRecordIndexByKey(cmb.EditValue),0]);

//0代表显示的第一列,以Properties.ListColumns为准,可以从这个集合中查找对应的字段名

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