我试图使用自定义类的数组作为我的组件的属性,但问题是值没有保存到组件,这意味着如果我设置值,保存所有内容并再次打开项目,组件的值消失…我的代码如下所示：
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.
我知道只有已发布的属性可以流式传输,但问题是我的属性是一个数组而且无法发布…
我的建议是使用DefineProperties()来提供自定义流,但我不知道如何使用数组执行此操作.
我认为的其他可能性是将TMyClass修改为TMyComponent可以作为它的父类的类,就像它在TChart中完成的那样,你可以为它添加不同类的系列.但我不知道这应该是什么课
TMyClass=class(T???????????)
有了它,我可以取出属性MyArray并创建TMyClass并添加到TMyComponent如下：
MyArray1.parent:= MyComponent1; MyArray2.parent:= MyComponent2; ...
.哪一个是更好的选择？或者还有其他更好的主意吗？
解决方法
最简单(和首选)的解决方案是将TMyClass更改为从TCollectionItem派生并将TMyComponent.FMyArray更改为TOwnedCollection.然后DFM将自动为您流式传输项目,您可以获得本机设计时支持,以创建和操作TMyClass对象及其属性.
试试这个：
unit Unit1;
interface
uses
Windows,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.