這是一個簡單的測試,演示了我在項目中遇到的問題,使用Delphi 2007.我使用TComponent類來存儲組件的各種狀態。但是從不調用Int64屬性編寫器方法(只設置目標字段)。因此,它不可能依靠作家更新的GUI的從TList或這樣的事情......爲什麼發佈的Int64屬性編寫器方法不會被調用 - 組件流
例如:
TTestClass = Class(TComponent)
Private
Fb: Int64;
Fa: Integer;
Procedure SetFa(Const Value: Integer);
Procedure SetFb(Const Value: Int64);
Published
Property a: Integer Read Fa Write SetFa;
Property b: Int64 Read Fb Write SetFb;
Public
Procedure SaveInstance(Var Str: TStream);
Procedure LoadInstance(Var Str: TStream);
Procedure ReallyLoadInstance(Var Str: TStream);
Procedure Assign(Source: TPersistent); Override;
End;
TForm1 = Class(TForm)
Button1: TButton;
Button2: TButton;
Button3: TButton;
Procedure Button1Click(Sender: TObject); // test: 1st step, save the class
Procedure Button2Click(Sender: TObject); // test: 2nd step, try and fail to reload
Procedure Button3Click(Sender: TObject); // test: 3rd step, successfull reloading
Private
TestClass: TTestClass;
Str: TStream;
Public
Constructor Create(AOwner: TComponent); Override;
Destructor Destroy; Override;
End;
Var
Form1: TForm1;
Implementation
{$R *.dfm}
Procedure TTestClass.SetFa(Const Value: Integer);
Begin
Fa := Value;
ShowMessage('ok for "simple types"....');
End;
Procedure TTestClass.SetFb(Const Value: Int64);
Begin
Fb := Value;
ShowMessage('and for the others');
End;
Procedure TTestClass.SaveInstance(Var Str: TStream);
Begin
Str.Position := 0;
Str.WriteComponent(Self);
End;
Procedure TTestClass.Assign(Source: TPersistent);
Begin
If Not (Source Is TTestClass) Then Inherited
Else
Begin
b := TTestClass(Source).Fb;
End;
End;
Procedure TTestClass.LoadInstance(Var Str: TStream);
Begin
Str.Position := 0;
// this will work for fa and not fb.
Str.ReadComponent(Self);
End;
Procedure TTestClass.ReallyLoadInstance(Var Str: TStream);
Begin
Str.Position := 0;
Assign(Str.ReadComponent(Nil));
End;
Constructor TForm1.Create(AOwner: TComponent);
Begin
RegisterClasses([TTestClass]);
Inherited;
TestClass := TTestClass.Create(Self);
Str := TmemoryStream.Create;
End;
Destructor TForm1.Destroy;
Begin
Str.Free;
Inherited;
End;
Procedure TForm1.Button1Click(Sender: TObject);
Begin
Str.Size := 0;
TestClass.SaveInstance(Str);
End;
Procedure TForm1.Button2Click(Sender: TObject);
Begin
If Str.Size = 0 Then Exit;
TestClass.LoadInstance(Str);
// guess what...only first message
End;
Procedure TForm1.Button3Click(Sender: TObject);
Begin
If Str.Size = 0 Then Exit;
TestClass.ReallyLoadInstance(Str);
End;
正如TypInfo.pas有一個「tkInt64」的情況下(這似乎調用「SetProc」過程),不應該發佈-int64-props使用「Writer」來設置(通常與其他「常用」類型一樣)?
你說得對,我」我完全忘記了默認值沒有寫入。但是,這仍然會顯示一個錯誤,正如您在第一個列表中所說的那樣。 – az01