我使用向导创建了一个带有 TComboBox 祖先的新组件。从编译、构建和安装，一切都很顺利。现在我尝试使用它，但出现以下错误：
Structure
Cannot resolve unit name 'SmartComboBox' at line 7 (7:55);
Undeclared identifier 'TSmartComboBox' at line 11 (11:21);
Messages
[dcc32 Fatal Error] main_u.pas(7): F2613 Unit 'SmartComboBox' not found.
用于新组件实施的 MRE
unit main_u;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, SmartComboBox;
type
TForm9 = class(TForm)
SmartComboBox1: TSmartComboBox;
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form9: TForm9;
implementation
{$R *.dfm}
end.
用于新组件安装程序包的 MRE
unit SmartComboBox;
interface
uses
System.SysUtils, System.Classes, Vcl.Controls, Vcl.StdCtrls,
Messages, Windows, StrUtils;
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
{ Private declarations }
FChar: Char; // @for UNICODE Filter
FIgnoreChar: boolean; // @for UNICODE Edit
FStoredItems: TStringList;
doFilter: boolean;
StoredItemIndex: Integer;
procedure StoredItemsChange(Sender: TObject);
procedure SetStoredItems(const Value: TStringList);
procedure CNCommand(var AMessage: TWMCommand); message CN_COMMAND;
function GetXText(var Key: Char): string;
function GetXSelStart: Integer;
protected
{ Protected declarations }
procedure KeyPress(var Key: Char); override;
// @Prevents a bug - typing values are appended when selecting a list while typing in Unicode
procedure EditWndProc(var Message: TMessage); override;
public
{ Public declarations }
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
procedure FilterItems;
procedure InitSmartCombo;
property StoredItems: TStringList read FStoredItems write SetStoredItems;
published
{ Published declarations }
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('My Components', [TSmartComboBox]);
end;
function TSmartComboBox.GetXText(var Key: Char): string;
var
tmp: string;
begin
if (Text = '') then // empty edit box
result := ''
else if SelLength > 0 then // has selection
begin
tmp := Copy(Text, SelStart + 1, SelLength);
result := ReplaceStr(Text, tmp, '');
end
else // not empty edit box and no selection
begin
tmp := Copy(Text, 1, SelStart);
result := tmp + Key;
result := result + Copy(Text, SelStart + 1, Length(Text) - SelStart);
Key := #0;
end;
end;
function TSmartComboBox.GetXSelStart: Integer;
begin
// empty edit box or has selection
if (Text = '') or (SelLength > 0) then
result := SelStart
else // not empty edit box and no selection
result := SelStart + 1;
end;
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
var
xSelStart: Integer;
xText: string;
begin
inherited;
if Ord(Key) = 8 then
FChar := Key;
if doFilter and not(Ord(Key) in [8, 13, 27]) then // BackSpace, Enter, ESC
begin
FChar := Key;
if DroppedDown then
Exit;
if Items.Count = 0 then
Exit;
// backup
xSelStart := GetXSelStart;
xText := GetXText(Key);
// dropdown
SendMessage(Handle, CB_SHOWDROPDOWN, 1, 0);
if xText.IsEmpty then
Exit;
// restore
Text := xText;
SelStart := xSelStart;
end;
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;
FIgnoreChar := False;
doFilter := False;
end;
destructor TSmartComboBox.Destroy;
begin
FStoredItems.Free;
inherited;
end;
procedure TSmartComboBox.EditWndProc(var Message: TMessage);
var
OldText: string;
begin
case Message.Msg of
WM_IME_ENDCOMPOSITION:
begin
OldText := Self.Text;
inherited;
FIgnoreChar := Self.Text = OldText;
end;
WM_CHAR:
begin
FIgnoreChar := False;
inherited;
end;
WM_IME_CHAR:
begin
if FIgnoreChar then
FIgnoreChar := False
else
inherited;
end;
else
inherited;
end;
end;
procedure TSmartComboBox.CNCommand(var AMessage: TWMCommand);
begin
// we have to process everything from our ancestor
inherited;
// @Filtering is applied to each Unicode being typed if it is being entered after the end of the text.
// @If you are typing in the middle of the text, do not apply filtering to the Unicode being typed
// (filtering is applied in units of completed Unicode characters)
if (SelStart < Length(Text)) and (FChar = #0) then
Exit;
// if we received the CBN_EDITUPDATE notification
if (AMessage.NotifyCode = CBN_EDITUPDATE) and doFilter then
begin
// fill the items with the matches
FilterItems;
end;
FChar := #0;
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 ContainsText(FStoredItems[I], Text) 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;
end.
我确定某事，某处我失踪了。