Delphi 将自动完成字符串分配给
我正在从此处使用autocomplete修改编辑控件: 我想从DB加载自动完成字符串。我在自动完成控件子体上声明了新属性:Delphi 将自动完成字符串分配给,delphi,autocomplete,controls,Delphi,Autocomplete,Controls,我正在从此处使用autocomplete修改编辑控件: 我想从DB加载自动完成字符串。我在自动完成控件子体上声明了新属性: FACDataSource : TDataSource; FACFieldName : string; 我调用此函数来加载自动完成字符串: procedure TAutoCompleteEdit.ReadSuggestions; begin FAutoCompleteSourceList.Clear; if (not Assigned(FACDataSourc
FACDataSource : TDataSource;
FACFieldName : string;
我调用此函数来加载自动完成字符串:
procedure TAutoCompleteEdit.ReadSuggestions;
begin
FAutoCompleteSourceList.Clear;
if (not Assigned(FACDataSource)) or (not Assigned(FACDataSource.DataSet)) or (not ACEnabled) then
exit;
with FACDataSource.DataSet do
begin
if Active and (RecordCount > 0) and (FACFieldName <> '') then
begin
First;
while not EOF do
begin
FAutoCompleteSourceList.Add(FACDataSource.DataSet.FieldByName(FACFieldName).AsString);
Next;
end;
if FAutoCompleteSourceList.Count > 0 then
ACStrings := FAutoCompleteSourceList;
end;
我在以下行中获得AccessViolation:FACList.FStrings.Assign(Value)代码>(读取地址xxxyy)<代码>值
已定义,在该点上不是垃圾(例如,在中,我可以在调试器中查看字符串列表)。'FStrings'是一个空字符串列表
当控件被放到窗体上时,它可以正常工作。但如果我将其放置在用户输入DBGridEH单元格时显示的自定义就地编辑器中,则不会发生这种情况
inplace编辑器如下所示:
unit UInplaceAutoCompleteEditor;
interface
uses UDBAutoComplete, UMyInplaceEditor, classes, windows, Controls, Buttons, DB;
type TInplaceAutoCompleteEditor = class(TMyInplaceEditor)
private
FEditor : TAutoCompleteEdit;
FButton : TSpeedButton;
FShowButton : boolean;
procedure SetShowButton(value : boolean);
public
constructor Create(AOwner : TComponent); override;
procedure SetFocus; override;
destructor Destroy; override;
protected
procedure EditorKeyDown(Sender : TObject; var Key : Word; Shift : TShiftState);
function GetACDataSource : TDataSource;
procedure SetACDataSource(value : TDataSource);
function GetACFieldName : string;
procedure SetACFieldName(value : string);
procedure SetACEnabled(value : boolean);
function GetACEnabled : boolean;
published
property Editor : TAutoCompleteEdit read FEditor;
property ACDataSource : TDataSource read GetACDataSource write SetACDataSource;
property ACFieldName : string read GetACFieldName write SetACFieldName;
property ACEnabled : boolean read GetACEnabled write SetACEnabled;
property Button : TSpeedButton read FButton;
property ShowButton : boolean read FShowButton write SetShowButton;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('nikolaev', [ TInplaceAutoCompleteEditor ]);
end;
{ TInplaceAutoCompleteEditor }
constructor TInplaceAutoCompleteEditor.Create(AOwner: TComponent);
begin
inherited;
FEditor := TAutoCompleteEdit.Create(self);
FEditor.Parent := self;
FEditor.Align := alClient;
FEditor.Visible := true;
FEditor.WantTabs := true;
FEditor.OnKeyDown := EditorKeyDown;
FButton := TSpeedButton.Create(self);
FButton.Parent := self;
FButton.Align := alRight;
self.FOwnHeight := -1;
self.FOwnWidth := -1;
SetShowButton(false);
end;
destructor TInplaceAutoCompleteEditor.Destroy;
begin
Feditor.Destroy;
FButton.Destroy;
inherited;
end;
procedure TInplaceAutoCompleteEditor.EditorKeyDown(Sender: TObject;
var Key: Word; Shift: TShiftState);
begin
if Key in [ VK_Return, VK_Tab ] then
begin
self.Value := FEditor.Text;
Key := 0;
ConfirmValue;
end;
if Key = VK_Escape then
begin
Key := 0;
CancelValue;
end;
inherited;
end;
function TInplaceAutoCompleteEditor.GetACDataSource: TDataSource;
begin
Result := FEditor.ACDataSource;
end;
function TInplaceAutoCompleteEditor.GetACEnabled: boolean;
begin
Result := FEditor.ACEnabled;
end;
function TInplaceAutoCompleteEditor.GetACFieldName: string;
begin
Result := FEditor.ACFieldName
end;
procedure TInplaceAutoCompleteEditor.SetACDataSource(value: TDataSource);
begin
FEditor.ACDataSource := value;
end;
procedure TInplaceAutoCompleteEditor.SetACEnabled(value: boolean);
begin
FEditor.ACEnabled := value;
end;
procedure TInplaceAutoCompleteEditor.SetACFieldName(value: string);
begin
FEditor.acfieldname := value;
end;
procedure TInplaceAutoCompleteEditor.SetFocus;
begin
inherited;
FEditor.SetFocus;
end;
procedure TInplaceAutoCompleteEditor.SetShowButton(value: boolean);
begin
if value <> FShowButton then
begin
FShowButton := value;
FButton.Visible := value;
end;
end;
end.
type
TAutoCompleteEdit = class(TEdit)
private
FACList: TEnumString;
....
type
TEnumString = class(TObject, IInterface, IEnumString)
private
function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
function _AddRef: Integer; stdcall;
function _Release: Integer; stdcall;
....
end;
function TEnumString.QueryInterface(const IID: TGUID; out Obj): HResult;
begin
if GetInterface(IID, Obj) then
Result := 0
else
Result := E_NOINTERFACE;
end;
function TEnumString._AddRef: Integer;
begin
Result := -1;
end;
function TEnumString._Release: Integer;
begin
Result := -1;
end;
destructor TAutoCompleteEdit.Destroy;
begin
FACList.Free;
inherited;
end;
InplaceEditor用于DBGridEH
的后代。在某些情况下,我覆盖ShowEditor和HideEditor以显示/隐藏我的编辑器
同样,autocomplete控件仅在嵌入inplaceeditor控件时引发异常
导致访问冲突的原因是什么?问题在于,您使用的mis代码处理接口引用计数。以下是相关摘录:
type
TEnumString = class(TInterfacedObject, IEnumString)
....
请注意,此类派生自TInterfacedObject
,因此它使用引用计数管理其生存期
然后代码是这样的:
unit UInplaceAutoCompleteEditor;
interface
uses UDBAutoComplete, UMyInplaceEditor, classes, windows, Controls, Buttons, DB;
type TInplaceAutoCompleteEditor = class(TMyInplaceEditor)
private
FEditor : TAutoCompleteEdit;
FButton : TSpeedButton;
FShowButton : boolean;
procedure SetShowButton(value : boolean);
public
constructor Create(AOwner : TComponent); override;
procedure SetFocus; override;
destructor Destroy; override;
protected
procedure EditorKeyDown(Sender : TObject; var Key : Word; Shift : TShiftState);
function GetACDataSource : TDataSource;
procedure SetACDataSource(value : TDataSource);
function GetACFieldName : string;
procedure SetACFieldName(value : string);
procedure SetACEnabled(value : boolean);
function GetACEnabled : boolean;
published
property Editor : TAutoCompleteEdit read FEditor;
property ACDataSource : TDataSource read GetACDataSource write SetACDataSource;
property ACFieldName : string read GetACFieldName write SetACFieldName;
property ACEnabled : boolean read GetACEnabled write SetACEnabled;
property Button : TSpeedButton read FButton;
property ShowButton : boolean read FShowButton write SetShowButton;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('nikolaev', [ TInplaceAutoCompleteEditor ]);
end;
{ TInplaceAutoCompleteEditor }
constructor TInplaceAutoCompleteEditor.Create(AOwner: TComponent);
begin
inherited;
FEditor := TAutoCompleteEdit.Create(self);
FEditor.Parent := self;
FEditor.Align := alClient;
FEditor.Visible := true;
FEditor.WantTabs := true;
FEditor.OnKeyDown := EditorKeyDown;
FButton := TSpeedButton.Create(self);
FButton.Parent := self;
FButton.Align := alRight;
self.FOwnHeight := -1;
self.FOwnWidth := -1;
SetShowButton(false);
end;
destructor TInplaceAutoCompleteEditor.Destroy;
begin
Feditor.Destroy;
FButton.Destroy;
inherited;
end;
procedure TInplaceAutoCompleteEditor.EditorKeyDown(Sender: TObject;
var Key: Word; Shift: TShiftState);
begin
if Key in [ VK_Return, VK_Tab ] then
begin
self.Value := FEditor.Text;
Key := 0;
ConfirmValue;
end;
if Key = VK_Escape then
begin
Key := 0;
CancelValue;
end;
inherited;
end;
function TInplaceAutoCompleteEditor.GetACDataSource: TDataSource;
begin
Result := FEditor.ACDataSource;
end;
function TInplaceAutoCompleteEditor.GetACEnabled: boolean;
begin
Result := FEditor.ACEnabled;
end;
function TInplaceAutoCompleteEditor.GetACFieldName: string;
begin
Result := FEditor.ACFieldName
end;
procedure TInplaceAutoCompleteEditor.SetACDataSource(value: TDataSource);
begin
FEditor.ACDataSource := value;
end;
procedure TInplaceAutoCompleteEditor.SetACEnabled(value: boolean);
begin
FEditor.ACEnabled := value;
end;
procedure TInplaceAutoCompleteEditor.SetACFieldName(value: string);
begin
FEditor.acfieldname := value;
end;
procedure TInplaceAutoCompleteEditor.SetFocus;
begin
inherited;
FEditor.SetFocus;
end;
procedure TInplaceAutoCompleteEditor.SetShowButton(value: boolean);
begin
if value <> FShowButton then
begin
FShowButton := value;
FButton.Visible := value;
end;
end;
end.
type
TAutoCompleteEdit = class(TEdit)
private
FACList: TEnumString;
....
type
TEnumString = class(TObject, IInterface, IEnumString)
private
function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
function _AddRef: Integer; stdcall;
function _Release: Integer; stdcall;
....
end;
function TEnumString.QueryInterface(const IID: TGUID; out Obj): HResult;
begin
if GetInterface(IID, Obj) then
Result := 0
else
Result := E_NOINTERFACE;
end;
function TEnumString._AddRef: Integer;
begin
Result := -1;
end;
function TEnumString._Release: Integer;
begin
Result := -1;
end;
destructor TAutoCompleteEdit.Destroy;
begin
FACList.Free;
inherited;
end;
因此,我们将保留对对象的引用,而不是对接口的引用。这看起来已经很可疑了
然后我们这样做:
constructor TAutoCompleteEdit.Create(AOwner: TComponent);
begin
inherited;
FACList := TEnumString.Create;
....
end;
destructor TAutoCompleteEdit.Destroy;
begin
FACList := nil;
inherited;
end;
这里没有任何东西可以让这个物体活着。在代码中的其他点,我们引用IEnumString
接口。但一旦该引用被释放,对象就会认为已经没有引用了。所以它被删除了。随后,代码引用了FACList
,它现在指向一个已被破坏的对象
解决此问题的一个简单方法是确保
tautompleedit
控件始终包含对接口的引用:
type
TAutoCompleteEdit = class(TEdit)
private
FACList: TEnumString;
FEnumString: IEnumString;
....
constructor TAutoCompleteEdit.Create(AOwner: TComponent);
begin
inherited;
FACList := TEnumString.Create;
FEnumString := FACList;
....
end;
通过此更改,您可以删除tautompleedit
的析构函数,因为FEnumString
后面的对象将被引用计数机制销毁
另一种解决方法是将
TEnumString
更改为禁用自动引用计数。看起来是这样的:
unit UInplaceAutoCompleteEditor;
interface
uses UDBAutoComplete, UMyInplaceEditor, classes, windows, Controls, Buttons, DB;
type TInplaceAutoCompleteEditor = class(TMyInplaceEditor)
private
FEditor : TAutoCompleteEdit;
FButton : TSpeedButton;
FShowButton : boolean;
procedure SetShowButton(value : boolean);
public
constructor Create(AOwner : TComponent); override;
procedure SetFocus; override;
destructor Destroy; override;
protected
procedure EditorKeyDown(Sender : TObject; var Key : Word; Shift : TShiftState);
function GetACDataSource : TDataSource;
procedure SetACDataSource(value : TDataSource);
function GetACFieldName : string;
procedure SetACFieldName(value : string);
procedure SetACEnabled(value : boolean);
function GetACEnabled : boolean;
published
property Editor : TAutoCompleteEdit read FEditor;
property ACDataSource : TDataSource read GetACDataSource write SetACDataSource;
property ACFieldName : string read GetACFieldName write SetACFieldName;
property ACEnabled : boolean read GetACEnabled write SetACEnabled;
property Button : TSpeedButton read FButton;
property ShowButton : boolean read FShowButton write SetShowButton;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('nikolaev', [ TInplaceAutoCompleteEditor ]);
end;
{ TInplaceAutoCompleteEditor }
constructor TInplaceAutoCompleteEditor.Create(AOwner: TComponent);
begin
inherited;
FEditor := TAutoCompleteEdit.Create(self);
FEditor.Parent := self;
FEditor.Align := alClient;
FEditor.Visible := true;
FEditor.WantTabs := true;
FEditor.OnKeyDown := EditorKeyDown;
FButton := TSpeedButton.Create(self);
FButton.Parent := self;
FButton.Align := alRight;
self.FOwnHeight := -1;
self.FOwnWidth := -1;
SetShowButton(false);
end;
destructor TInplaceAutoCompleteEditor.Destroy;
begin
Feditor.Destroy;
FButton.Destroy;
inherited;
end;
procedure TInplaceAutoCompleteEditor.EditorKeyDown(Sender: TObject;
var Key: Word; Shift: TShiftState);
begin
if Key in [ VK_Return, VK_Tab ] then
begin
self.Value := FEditor.Text;
Key := 0;
ConfirmValue;
end;
if Key = VK_Escape then
begin
Key := 0;
CancelValue;
end;
inherited;
end;
function TInplaceAutoCompleteEditor.GetACDataSource: TDataSource;
begin
Result := FEditor.ACDataSource;
end;
function TInplaceAutoCompleteEditor.GetACEnabled: boolean;
begin
Result := FEditor.ACEnabled;
end;
function TInplaceAutoCompleteEditor.GetACFieldName: string;
begin
Result := FEditor.ACFieldName
end;
procedure TInplaceAutoCompleteEditor.SetACDataSource(value: TDataSource);
begin
FEditor.ACDataSource := value;
end;
procedure TInplaceAutoCompleteEditor.SetACEnabled(value: boolean);
begin
FEditor.ACEnabled := value;
end;
procedure TInplaceAutoCompleteEditor.SetACFieldName(value: string);
begin
FEditor.acfieldname := value;
end;
procedure TInplaceAutoCompleteEditor.SetFocus;
begin
inherited;
FEditor.SetFocus;
end;
procedure TInplaceAutoCompleteEditor.SetShowButton(value: boolean);
begin
if value <> FShowButton then
begin
FShowButton := value;
FButton.Visible := value;
end;
end;
end.
type
TAutoCompleteEdit = class(TEdit)
private
FACList: TEnumString;
....
type
TEnumString = class(TObject, IInterface, IEnumString)
private
function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
function _AddRef: Integer; stdcall;
function _Release: Integer; stdcall;
....
end;
function TEnumString.QueryInterface(const IID: TGUID; out Obj): HResult;
begin
if GetInterface(IID, Obj) then
Result := 0
else
Result := E_NOINTERFACE;
end;
function TEnumString._AddRef: Integer;
begin
Result := -1;
end;
function TEnumString._Release: Integer;
begin
Result := -1;
end;
destructor TAutoCompleteEdit.Destroy;
begin
FACList.Free;
inherited;
end;
然后您需要tautompleedit
析构函数如下所示:
unit UInplaceAutoCompleteEditor;
interface
uses UDBAutoComplete, UMyInplaceEditor, classes, windows, Controls, Buttons, DB;
type TInplaceAutoCompleteEditor = class(TMyInplaceEditor)
private
FEditor : TAutoCompleteEdit;
FButton : TSpeedButton;
FShowButton : boolean;
procedure SetShowButton(value : boolean);
public
constructor Create(AOwner : TComponent); override;
procedure SetFocus; override;
destructor Destroy; override;
protected
procedure EditorKeyDown(Sender : TObject; var Key : Word; Shift : TShiftState);
function GetACDataSource : TDataSource;
procedure SetACDataSource(value : TDataSource);
function GetACFieldName : string;
procedure SetACFieldName(value : string);
procedure SetACEnabled(value : boolean);
function GetACEnabled : boolean;
published
property Editor : TAutoCompleteEdit read FEditor;
property ACDataSource : TDataSource read GetACDataSource write SetACDataSource;
property ACFieldName : string read GetACFieldName write SetACFieldName;
property ACEnabled : boolean read GetACEnabled write SetACEnabled;
property Button : TSpeedButton read FButton;
property ShowButton : boolean read FShowButton write SetShowButton;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('nikolaev', [ TInplaceAutoCompleteEditor ]);
end;
{ TInplaceAutoCompleteEditor }
constructor TInplaceAutoCompleteEditor.Create(AOwner: TComponent);
begin
inherited;
FEditor := TAutoCompleteEdit.Create(self);
FEditor.Parent := self;
FEditor.Align := alClient;
FEditor.Visible := true;
FEditor.WantTabs := true;
FEditor.OnKeyDown := EditorKeyDown;
FButton := TSpeedButton.Create(self);
FButton.Parent := self;
FButton.Align := alRight;
self.FOwnHeight := -1;
self.FOwnWidth := -1;
SetShowButton(false);
end;
destructor TInplaceAutoCompleteEditor.Destroy;
begin
Feditor.Destroy;
FButton.Destroy;
inherited;
end;
procedure TInplaceAutoCompleteEditor.EditorKeyDown(Sender: TObject;
var Key: Word; Shift: TShiftState);
begin
if Key in [ VK_Return, VK_Tab ] then
begin
self.Value := FEditor.Text;
Key := 0;
ConfirmValue;
end;
if Key = VK_Escape then
begin
Key := 0;
CancelValue;
end;
inherited;
end;
function TInplaceAutoCompleteEditor.GetACDataSource: TDataSource;
begin
Result := FEditor.ACDataSource;
end;
function TInplaceAutoCompleteEditor.GetACEnabled: boolean;
begin
Result := FEditor.ACEnabled;
end;
function TInplaceAutoCompleteEditor.GetACFieldName: string;
begin
Result := FEditor.ACFieldName
end;
procedure TInplaceAutoCompleteEditor.SetACDataSource(value: TDataSource);
begin
FEditor.ACDataSource := value;
end;
procedure TInplaceAutoCompleteEditor.SetACEnabled(value: boolean);
begin
FEditor.ACEnabled := value;
end;
procedure TInplaceAutoCompleteEditor.SetACFieldName(value: string);
begin
FEditor.acfieldname := value;
end;
procedure TInplaceAutoCompleteEditor.SetFocus;
begin
inherited;
FEditor.SetFocus;
end;
procedure TInplaceAutoCompleteEditor.SetShowButton(value: boolean);
begin
if value <> FShowButton then
begin
FShowButton := value;
FButton.Visible := value;
end;
end;
end.
type
TAutoCompleteEdit = class(TEdit)
private
FACList: TEnumString;
....
type
TEnumString = class(TObject, IInterface, IEnumString)
private
function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
function _AddRef: Integer; stdcall;
function _Release: Integer; stdcall;
....
end;
function TEnumString.QueryInterface(const IID: TGUID; out Obj): HResult;
begin
if GetInterface(IID, Obj) then
Result := 0
else
Result := E_NOINTERFACE;
end;
function TEnumString._AddRef: Integer;
begin
Result := -1;
end;
function TEnumString._Release: Integer;
begin
Result := -1;
end;
destructor TAutoCompleteEdit.Destroy;
begin
FACList.Free;
inherited;
end;
最后一个选择是完全避免持有
TEnumString
,而只持有IEnumString
引用。让引用计数像在第一个解决方案中一样管理生存期。但是,您需要实现另一个接口,该接口允许tautompleedit
获取TStrings
对象。@KenWhite您的链接答案在其他方面非常好。如果你能在那里修改代码,那也许是最好的。@David:完成了,谢谢。(我选择了你的第一个建议,因为在我看来这是最干净的。)@KenWhite谢谢。我能看到这三个选项的优点,我想这就是为什么我没能把我的颜色钉在桅杆上!