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几句话给你讲不清楚,我又没有现成的代码
你去书店看看,有一本书专门有一章讲RTTI,不过我忘了是那本书了
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, ExtCtrls, DBClient, MidasCon, MConnect;type TMainForm = class(TForm)
pnlTop: TPanel;
pnlLeft: TPanel;
lbBaseClassInfo: TListBox;
spSplit: TSplitter;
lblBaseClassInfo: TLabel;
pnlRight: TPanel;
lblClassProperties: TLabel;
lbPropList: TListBox;
lbSampClasses: TListBox;
procedure FormCreate(Sender: TObject);
procedure lbSampClassesClick(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;var
MainForm: TMainForm;implementation
uses TypInfo;{$R *.DFM}function CreateAClass(const AClassName: string): TObject;
{ This method illustrates how you can create a class from the class name. Note
that this requires that you register the class using RegisterClasses() as
show in the initialization method of this unit. }
var
C : TFormClass;
SomeObject: TObject;
begin
C := TFormClass(FindClass(AClassName));
SomeObject := C.Create(nil);
Result := SomeObject;
end;
procedure GetBaseClassInfo(AClass: TObject; AStrings: TStrings);
{ This method obtains some basic RTTI data from the given object and adds that
information to the AStrings parameter. }
var
ClassTypeInfo: PTypeInfo;
ClassTypeData: PTypeData;
EnumName: String;
begin
ClassTypeInfo := AClass.ClassInfo;
ClassTypeData := GetTypeData(ClassTypeInfo);
with AStrings do
begin
Add(Format('Class Name: %s', [ClassTypeInfo.Name]));
EnumName := GetEnumName(TypeInfo(TTypeKind), Integer(ClassTypeInfo.Kind));
Add(Format('Kind: %s', [EnumName]));
Add(Format('Size: %d', [AClass.InstanceSize]));
Add(Format('Defined in: %s.pas', [ClassTypeData.UnitName]));
Add(Format('Num Properties: %d',[ClassTypeData.PropCount]));
end;
end;procedure GetClassAncestry(AClass: TObject; AStrings: TStrings);
{ This method retrieves the ancestry of a given object and adds the
class names of the ancestry to the AStrings parameter. }
var
AncestorClass: TClass;
begin
AncestorClass := AClass.ClassParent;
{ Iterate through the Parent classes starting with Sender's
Parent until the end of the ancestry is reached. }
AStrings.Add('Class Ancestry');
while AncestorClass <> nil do
begin
AStrings.Add(Format(' %s',[AncestorClass.ClassName]));
AncestorClass := AncestorClass.ClassParent;
end;
end;
procedure GetClassProperties(AClass: TObject; AStrings: TStrings);
{ This method retrieves the property names and types for the given object
and adds that information to the AStrings parameter. }
var
PropList: PPropList;
ClassTypeInfo: PTypeInfo;
ClassTypeData: PTypeData;
i: integer;
NumProps: Integer;
begin ClassTypeInfo := AClass.ClassInfo;
ClassTypeData := GetTypeData(ClassTypeInfo); if ClassTypeData.PropCount <> 0 then
begin
// allocate the memory needed to hold the references to the TPropInfo
// structures on the number of properties.
GetMem(PropList, SizeOf(PPropInfo) * ClassTypeData.PropCount);
try
// fill PropList with the pointer references to the TPropInfo structures
GetPropInfos(AClass.ClassInfo, PropList);
for i := 0 to ClassTypeData.PropCount - 1 do
// filter out properties that are events ( method pointer properties)
if not (PropList[i]^.PropType^.Kind = tkMethod) then
AStrings.Add(Format('%s: %s', [PropList[i]^.Name, PropList[i]^.PropType^.Name])); // Now get properties that are events (method pointer properties)
NumProps := GetPropList(AClass.ClassInfo, [tkMethod], PropList);
if NumProps <> 0 then begin
AStrings.Add('');
AStrings.Add(' EVENTS ================ ');
AStrings.Add('');
end;
// Fill the AStrings with the events.
for i := 0 to NumProps - 1 do
AStrings.Add(Format('%s: %s', [PropList[i]^.Name, PropList[i]^.PropType^.Name])); finally
FreeMem(PropList, SizeOf(PPropInfo) * ClassTypeData.PropCount);
end;
end;end;procedure TMainForm.FormCreate(Sender: TObject);
begin
// Add some example classes to the list box.
lbSampClasses.Items.Add('TApplication');
lbSampClasses.Items.Add('TButton');
lbSampClasses.Items.Add('TForm');
lbSampClasses.Items.Add('TListBox');
lbSampClasses.Items.Add('TPaintBox');
lbSampClasses.Items.Add('TMidasConnection');
lbSampClasses.Items.Add('TFindDialog');
lbSampClasses.Items.Add('TOpenDialog');
lbSampClasses.Items.Add('TTimer');
lbSampClasses.Items.Add('TComponent');
lbSampClasses.Items.Add('TGraphicControl');
end;procedure TMainForm.lbSampClassesClick(Sender: TObject);
var
SomeComp: TObject;
begin
lbBaseClassInfo.Items.Clear;
lbPropList.Items.Clear; // Create an instance of the selected class.
SomeComp := CreateAClass(lbSampClasses.Items[lbSampClasses.ItemIndex]);
try
GetBaseClassInfo(SomeComp, lbBaseClassInfo.Items);
GetClassAncestry(SomeComp, lbBaseClassInfo.Items);
GetClassProperties(SomeComp, lbPropList.Items);
finally
SomeComp.Free;
end;
end;initialization
begin
RegisterClasses([TApplication, TButton, TForm, TListBox, TPaintBox,
TMidasConnection, TFindDialog, TOpenDialog, TTimer, TComponent,
TGraphicControl]);
end;end.