作爲屬性的自定義類的數組

Question

我想使用自定義類的數組作爲我的組件的屬性，但問題是值未保存到組件，這意味着如果我設置值，保存所有工作，再次打開該項目，該值組件將消失...我的代碼如下所示：

unit Unit1; 

interface 

uses Windows, ExtCtrls,Classes,Controls; 

type 

    TMyClass=class(TPersistent) 
    private 
    FName: string; 
    FValue: double; 
    public 
    property Name: string read FName write FName; 
    property Value: double read FValue write FValue; 
    end; 

    TMyComponent= class(TCustomPanel) 
    private 
    FMyArray: array[0..200] of TMyClass; 

    function GetmyArray(Index: Integer): TMyClass; 

    procedure SetMyArray(index: Integer; Value: TMyClass); 
    public 
    property myArray[index: Integer]: TMyClass read GetMyArray write SetMyArray; 
    end; 

implementation 

function TMyComponent.GetmyArray(Index: Integer): TMyClass; 
begin 
    result:= FmyArray[Index]; 
end; 

procedure TMyComponent.SetMyArray(index: Integer; Value: TMyClass); 
begin 
    FMyArray[index].FName:= Value.FName; 
    FMyArray[index].FValue:= Value.FValue; 
end; 

end. 

我知道，只有已發佈的屬性可以被串流播放，但問題是，我的財產是一個數組，它不能被髮布... 我的建議是使用DefineProperties()來提供自定義流，但我不知道如何做到這一點與數組。 我認爲其他的可能性是將TMyClass修改爲TMyComponent可以作爲其父類的類，就像在TChart中完成的一樣，您可以在其中添加不同的系列類。但我不知道是什麼類，這應該是

TMyClass=class(T???????????) 

有了，我可以拿出財產MYARRAY創造TMyClass並添加到TMyComponent如下所示：

MyArray1.parent:= MyComponent1; 
MyArray2.parent:= MyComponent2; 
... 

。哪一個更好？或者還有其他更好的想法嗎？

Answer 1

的simpliest（和優選的）解決方案是改變TMyClass從TCollectionItem導出並改變TMyComponent.FMyArray到TOwnedCollection。然後，DFM將自動爲您流式傳輸項目，並且您可以獲得本機設計時支持，以創建和操作對象及其屬性。

試試這個：

unit Unit1; 

interface 

uses 
    Windows, ExtCtrls, Classes, Controls; 

type 
    TMyClass = class(TCollectionItem) 
    private 
    FName: string; 
    FValue: double; 

    procedure SetName(const AValue: string); 
    procedure SetValue(AValue: double); 
    public 
    procedure Assign(ASource: TPersistent); override; 
    published 
    property Name: string read FName write SetName; 
    property Value: double read FValue write SetValue; 
    end; 

    TMyArray = class(TOwnedCollection) 
    private 
    function GetItem(Index: Integer): TMyClass; 
    procedure SetItem(Index: Integer; const Value: TMyClass); 
    public 
    constructor Create(AOwner: TPersistent); 
    function Add: TMyClass; reintroduce; 
    function Insert(Index: Integer): TMyClass; reintroduce; 
    property Items[Index: Integer]: TMyClass read GetItem write SetItem; default; 
    end; 

    TMyComponent = class(TCustomPanel) 
    private 
    FMyArray: TMyArray; 

    procedure SetMyArray(Value: TMyArray); 
    public 
    constructor Create(AOwner: TComponent); override; 
    destructor Destroy; override; 
    published 
    property myArray: TMyArray read FMyArray write SetMyArray; 
    end; 

implementation 

procedure TMyClass.Assign(ASource: TPersistent); 
begin 
    if ASource is TMyClass then 
    begin 
    with TMyClass(ASource) do 
    begin 
     Self.FName := Name; 
     Self.FValue := Value; 
    end; 
    Changed(False); 
    end else 
    inherited; 
end; 

procedure TMyClass.SetName(const AValue: string); 
begin 
    if FName <> AValue then 
    begin 
    FName := AValue; 
    Changed(False); 
    end; 
end; 

procedure TMyClass.SetValue(AValue: double); 
begin 
    if FValue <> AValue then 
    begin 
    FValue := AValue; 
    Changed(False); 
    end; 
end; 

constructor TMyArray.Create(AOwner: TPersistent); 
begin 
    inherited Create(AOwner, TMyClass); 
end; 

function TMyArray.GetItem(Index: Integer): TMyClass; 
begin 
    Result := TMyClass(inherited GetItem(Index)); 
end; 

procedure TMyArray.SetItem(Index: Integer; const Value: TMyClass); 
begin 
    inherited SetItem(Index, Value); 
end; 

function TMyArray.Add: TMyClass; 
begin 
    Result := TMyClass(inherited Add); 
end; 

function TMyArray.Insert(Index: Integer): TMyClass; 
begin 
    Result := TMyClass(inherited Insert(Index)); 
end; 

constructor TMyComponent.Create(AOwner: TComponent); 
begin 
    inherited; 
    FMyArray := TMyArray.Create(Self); 
end; 

destructor TMyComponent.Destroy; 
begin 
    FMyArray.Free; 
    inherited; 
end; 

procedure TMyComponent.SetMyArray(Value: TMyArray); 
begin 
    FMyArray.Assign(Value); 
end; 

end. 

Answer 2

我投票給DefineProperties！必要的代碼可能如下所示（在陣列中的實例假設無爲nil）：

procedure TMyComponent.DefineProperties(Filer: TFiler); 
begin 
    inherited; 
    Filer.DefineProperty('MyArray', ReadMyArray, WriteMyArray, true); 
end; 

procedure TMyComponent.ReadMyArray(Reader: TReader); 
var 
    N: Integer; 
begin 
    N := 0; 
    Reader.ReadListBegin; 
    while not Reader.EndOfList do begin 
    Reader.ReadListBegin; 
    FMyArray[N].Name := Reader.ReadString; 
    FMyArray[N].Value := Reader.ReadFloat; 
    Reader.ReadListEnd; 
    Inc(N); 
    end; 
    Reader.ReadListEnd; 
end; 

procedure TMyComponent.WriteMyArray(Writer: TWriter); 
var 
    I: Integer; 
begin 
    Writer.WriteListBegin; 
    for I := 0 to High(FMyArray) do begin 
    Writer.WriteListBegin; 
    Writer.WriteString(FMyArray[I].Name); 
    Writer.WriteFloat(FMyArray[I].Value); 
    Writer.WriteListEnd; 
    end; 
    Writer.WriteListEnd; 
end;