偶看新闻终结者4 百度影音:DevExpress部分使用技巧(原创)_大海拾贝
来源：百度文库 编辑：偶看新闻 时间：2024/05/04 18:41:39
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;
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;
end;
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;
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;
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;
end;
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;
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;
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;
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;
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;
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