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;
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