delphi - una - ¿Cómo hacer un cuadro combinado con el soporte de autocompletar de búsqueda de texto completo?

lista desplegable con sugerencias de búsqueda excel

Question

Me gustaría que un usuario pueda escribir la segunda o tercera palabra de un elemento TComboBox y que ese elemento aparezca en las opciones desplegables AutoSuggest

Por ejemplo, un cuadro combinado contiene los elementos:

• Mr John Brown
• Sra. Amanda Brown
• Sr. Brian Jones
• Sra. Samantha Smith

Cuando el usuario escribe "Br", aparece el menú desplegable:

• Mr John Brown
• Sra. Amanda Brown
• Sr. Brian Jones

y cuando el usuario escribe "Jo", aparece el menú desplegable:

• Mr John Brown
• Sr. Brian Jones

El problema es que la funcionalidad AutoSuggest solo incluye elementos en la lista desplegable que comienzan con lo que el usuario ha ingresado y, por lo tanto, en los ejemplos anteriores, nada aparecerá en el menú desplegable.

¿Es posible usar la interfaz IAutoComplete y / u otras interfaces relacionadas para evitar este problema?

Answer 1

El siguiente ejemplo usa la clase interpuesta del componente TComboBox . La principal diferencia con respecto a la clase original es que los elementos se almacenan en la propiedad separada StoredItems lugar de
los Items como siempre (usados ​​debido a la simplicidad).

StoredItems está siendo observado por el evento OnChange y cada vez que los cambie (por ejemplo, agregando o eliminando de esta lista de cadenas), el filtro actual lo reflejará incluso cuando el combo
la lista se deja caer

El punto principal aquí es capturar la notificación de mensaje CBN_EDITUPDATE que se envía cada vez que se modifica el texto de edición del combo pero no se procesa todavía. Cuando llega, solo busca en la lista StoredItems lo que ha escrito en la edición combinada y completa la propiedad Items con coincidencias.

Para la búsqueda de texto se usa ContainsText para que la búsqueda no distinga entre mayúsculas y minúsculas. Olvide mencionar,
la función AutoComplete debe desactivarse porque tiene su propia lógica no bienvenida para este propósito.

unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, StrUtils, ExtCtrls;
type
TComboBox = class(StdCtrls.TComboBox)
private
FStoredItems: TStringList;
procedure FilterItems;
procedure StoredItemsChange(Sender: TObject);
procedure SetStoredItems(const Value: TStringList);
procedure CNCommand(var AMessage: TWMCommand); message CN_COMMAND;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
property StoredItems: TStringList read FStoredItems write SetStoredItems;
end;
type
TForm1 = class(TForm)
ComboBox1: TComboBox;
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
constructor TComboBox.Create(AOwner: TComponent);
begin
inherited;
AutoComplete := False;
FStoredItems := TStringList.Create;
FStoredItems.OnChange := StoredItemsChange;
end;
destructor TComboBox.Destroy;
begin
FStoredItems.Free;
inherited;
end;
procedure TComboBox.CNCommand(var AMessage: TWMCommand);
begin
// we have to process everything from our ancestor
inherited;
// if we received the CBN_EDITUPDATE notification
if AMessage.NotifyCode = CBN_EDITUPDATE then
// fill the items with the matches
FilterItems;
end;
procedure TComboBox.FilterItems;
var
I: Integer;
Selection: TSelection;
begin
// store the current combo edit selection
SendMessage(Handle, CB_GETEDITSEL, WPARAM(@Selection.StartPos),
LPARAM(@Selection.EndPos));
// begin with the items update
Items.BeginUpdate;
try
// if the combo edit is not empty, then clear the items
// and search through the FStoredItems
if Text <> '''' then
begin
// clear all items
Items.Clear;
// iterate through all of them
for I := 0 to FStoredItems.Count - 1 do
// check if the current one contains the text in edit
if ContainsText(FStoredItems[I], Text) then
// and if so, then add it to the items
Items.Add(FStoredItems[I]);
end
// else the combo edit is empty
else
// so then we''ll use all what we have in the FStoredItems
Items.Assign(FStoredItems)
finally
// finish the items update
Items.EndUpdate;
end;
// and restore the last combo edit selection
SendMessage(Handle, CB_SETEDITSEL, 0, MakeLParam(Selection.StartPos,
Selection.EndPos));
end;
procedure TComboBox.StoredItemsChange(Sender: TObject);
begin
if Assigned(FStoredItems) then
FilterItems;
end;
procedure TComboBox.SetStoredItems(const Value: TStringList);
begin
if Assigned(FStoredItems) then
FStoredItems.Assign(Value)
else
FStoredItems := Value;
end;
procedure TForm1.FormCreate(Sender: TObject);
var
ComboBox: TComboBox;
begin
// here''s one combo created dynamically
ComboBox := TComboBox.Create(Self);
ComboBox.Parent := Self;
ComboBox.Left := 10;
ComboBox.Top := 10;
ComboBox.Text := ''Br'';
// here''s how to fill the StoredItems
ComboBox.StoredItems.BeginUpdate;
try
ComboBox.StoredItems.Add(''Mr John Brown'');
ComboBox.StoredItems.Add(''Mrs Amanda Brown'');
ComboBox.StoredItems.Add(''Mr Brian Jones'');
ComboBox.StoredItems.Add(''Mrs Samantha Smith'');
finally
ComboBox.StoredItems.EndUpdate;
end;
// and here''s how to assign the Items of the combo box from the form
// to the StoredItems; note that if you''ll use this, you have to do
// it before you type something into the combo''s edit, because typing
// may filter the Items, so they would get modified
ComboBox1.StoredItems.Assign(ComboBox1.Items);
end;
end.

Answer 2

En la configuración del evento OnDropDown manipulado, los elementos TComboBox filtrados por:

• Función Pos
• RegEx
• o algo aún más avanzado

desde una lista de cadenas completa externa. O mejor, escribe tu propio descendiente TComboBox (TCustomComboBox).

Answer 3

Este código era bastante bueno en realidad, solo solucioné el error al manejar los mensajes cuando se desplegaba el combo, algunas interacciones menores con el comportamiento de TComboBox y lo hacía un poco más amigable para el usuario. Para usarlo solo invoque InitSmartCombo después de completar la lista de elementos.

TSmartComboBox reemplaza a TComboBox, si invoca InitSmartCombo se comporta como un combo inteligente, de lo contrario, actúa como TComboBox estándar

unit SmartCombo;
interface
uses stdctrls,classes,messages,controls,windows,sysutils;
type
TSmartComboBox = class(TComboBox)
// Usage:
// Same as TComboBox, just invoke InitSmartCombo after Items list is filled with data.
// After InitSmartCombo is invoked, StoredItems is assigned and combo starts to behave as a smart combo.
// If InitSmartCombo is not invoked it acts as standard TComboBox, it is safe to bulk replace all TComboBox in application with TSmartComboBox
private
FStoredItems: TStringList;
dofilter:boolean;
storeditemindex:integer;
procedure FilterItems;
procedure StoredItemsChange(Sender: TObject);
procedure SetStoredItems(const Value: TStringList);
procedure CNCommand(var AMessage: TWMCommand); message CN_COMMAND;
protected
procedure KeyPress(var Key: Char); override;
procedure CloseUp; override;
procedure Click; override;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
property StoredItems: TStringList read FStoredItems write SetStoredItems;
procedure InitSmartCombo;
end;
implementation
procedure TSmartComboBox.KeyPress(var Key: Char); // combo dropdown must be done in keypress, if its done on CBN_EDITUPDATE it messes up whole message processing mumbo-jumbo
begin
inherited;
if dofilter and not (ord(key) in [13,27]) then begin
if (items.Count<>0) and not droppeddown then SendMessage(Handle, CB_SHOWDROPDOWN, 1, 0) // something matched -> dropdown combo to display results
end;
end;
procedure TSmartComboBox.CloseUp; // ugly workaround for some wierd combobox/modified code interactions
var x:string;
begin
if dofilter then begin
if (items.count=1) and (itemindex=0) then text:=items[itemindex]
else if ((text<>'''') and (itemindex<>-1) and (text<>items[itemindex])) or ((text='''') and(itemindex=0)) then begin
storeditemindex:=itemindex;
x:=text;
itemindex:=items.indexof(text);
if itemindex=-1 then text:=x;
end
else storeditemindex:=-1;
end;
inherited;
end;
procedure TSmartComboBox.Click; // ugly workaround for some weird combobox/modified code interactions
begin
if dofilter then begin
if storeditemindex<>-1 then itemindex:=storeditemindex;
storeditemindex:=-1;
end;
inherited;
end;
procedure TSmartComboBox.InitSmartCombo;
begin
FStoredItems.OnChange:=nil;
StoredItems.Assign(Items);
AutoComplete := False;
FStoredItems.OnChange := StoredItemsChange;
dofilter:=true;
storeditemindex:=-1;
end;
constructor TSmartComboBox.Create(AOwner: TComponent);
begin
inherited;
FStoredItems := TStringList.Create;
dofilter:=false;
end;
destructor TSmartComboBox.Destroy;
begin
FStoredItems.Free;
inherited;
end;
procedure TSmartComboBox.CNCommand(var AMessage: TWMCommand);
begin
// we have to process everything from our ancestor
inherited;
// if we received the CBN_EDITUPDATE notification
if (AMessage.NotifyCode = CBN_EDITUPDATE) and dofilter then begin
// fill the items with the matches
FilterItems;
end;
end;
procedure TSmartComboBox.FilterItems;
var
I: Integer;
Selection: TSelection;
begin
// store the current combo edit selection
SendMessage(Handle, CB_GETEDITSEL, WPARAM(@Selection.StartPos), LPARAM(@Selection.EndPos));
// begin with the items update
Items.BeginUpdate;
try
// if the combo edit is not empty, then clear the items
// and search through the FStoredItems
if Text <> '''' then begin
// clear all items
Items.Clear;
// iterate through all of them
for I := 0 to FStoredItems.Count - 1 do begin
// check if the current one contains the text in edit, case insensitive
if (Pos( uppercase(Text), uppercase(FStoredItems[I]) )>0) then begin
// and if so, then add it to the items
Items.Add(FStoredItems[I]);
end;
end;
end else begin
// else the combo edit is empty
// so then we''ll use all what we have in the FStoredItems
Items.Assign(FStoredItems);
end;
finally
// finish the items update
Items.EndUpdate;
end;
// and restore the last combo edit selection
SendMessage(Handle, CB_SETEDITSEL, 0, MakeLParam(Selection.StartPos, Selection.EndPos));
end;
procedure TSmartComboBox.StoredItemsChange(Sender: TObject);
begin
if Assigned(FStoredItems) then
FilterItems;
end;
procedure TSmartComboBox.SetStoredItems(const Value: TStringList);
begin
if Assigned(FStoredItems) then
FStoredItems.Assign(Value)
else
FStoredItems := Value;
end;
procedure Register;
begin
RegisterComponents(''Standard'', [TSmartComboBox]);
end;
end.

Answer 4

Gracias por el corazón! Con un poco de retrabajo, creo que es bastante correcto.

unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, StrUtils, ExtCtrls;
type
TComboBox = class(StdCtrls.TComboBox)
private
FStoredItems: TStringList;
procedure FilterItems;
procedure StoredItemsChange(Sender: TObject);
procedure SetStoredItems(const Value: TStringList);
procedure CNCommand(var AMessage: TWMCommand); message CN_COMMAND;
protected
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
property StoredItems: TStringList read FStoredItems write SetStoredItems;
end;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
private
public
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
{}constructor TComboBox.Create(AOwner: TComponent);
begin
inherited;
AutoComplete := False;
FStoredItems := TStringList.Create;
FStoredItems.OnChange := StoredItemsChange;
end;
{}destructor TComboBox.Destroy;
begin
FStoredItems.Free;
inherited;
end;
{}procedure TComboBox.CNCommand(var AMessage: TWMCommand);
begin
// we have to process everything from our ancestor
inherited;
// if we received the CBN_EDITUPDATE notification
if AMessage.NotifyCode = CBN_EDITUPDATE then begin
// fill the items with the matches
FilterItems;
end;
end;
{}procedure TComboBox.FilterItems;
type
TSelection = record
StartPos, EndPos: Integer;
end;
var
I: Integer;
Selection: TSelection;
xText: string;
begin
// store the current combo edit selection
SendMessage(Handle, CB_GETEDITSEL, WPARAM(@Selection.StartPos), LPARAM(@Selection.EndPos));
// begin with the items update
Items.BeginUpdate;
try
// if the combo edit is not empty, then clear the items
// and search through the FStoredItems
if Text <> '''' then begin
// clear all items
Items.Clear;
// iterate through all of them
for I := 0 to FStoredItems.Count - 1 do begin
// check if the current one contains the text in edit
// if ContainsText(FStoredItems[I], Text) then
if Pos( Text, FStoredItems[I])>0 then begin
// and if so, then add it to the items
Items.Add(FStoredItems[I]);
end;
end;
end else begin
// else the combo edit is empty
// so then we''ll use all what we have in the FStoredItems
Items.Assign(FStoredItems)
end;
finally
// finish the items update
Items.EndUpdate;
end;
// and restore the last combo edit selection
xText := Text;
SendMessage(Handle, CB_SHOWDROPDOWN, Integer(True), 0);
if (Items<>nil) and (Items.Count>0) then begin
ItemIndex := 0;
end else begin
ItemIndex := -1;
end;
Text := xText;
SendMessage(Handle, CB_SETEDITSEL, 0, MakeLParam(Selection.StartPos, Selection.EndPos));
end;
{}procedure TComboBox.StoredItemsChange(Sender: TObject);
begin
if Assigned(FStoredItems) then
FilterItems;
end;
{}procedure TComboBox.SetStoredItems(const Value: TStringList);
begin
if Assigned(FStoredItems) then
FStoredItems.Assign(Value)
else
FStoredItems := Value;
end;
//=====================================================================
{}procedure TForm1.FormCreate(Sender: TObject);
var
ComboBox: TComboBox;
xList:TStringList;
begin
// here''s one combo created dynamically
ComboBox := TComboBox.Create(Self);
ComboBox.Parent := Self;
ComboBox.Left := 8;
ComboBox.Top := 8;
ComboBox.Width := Width-16;
// ComboBox.Style := csDropDownList;
// here''s how to fill the StoredItems
ComboBox.StoredItems.BeginUpdate;
try
xList:=TStringList.Create;
xList.LoadFromFile(''list.txt'');
ComboBox.StoredItems.Assign( xList);
finally
ComboBox.StoredItems.EndUpdate;
end;
ComboBox.DropDownCount := 24;
// and here''s how to assign the Items of the combo box from the form
// to the StoredItems; note that if you''ll use this, you have to do
// it before you type something into the combo''s edit, because typing
// may filter the Items, so they would get modified
ComboBox.StoredItems.Assign(ComboBox.Items);
end;
end.