Returns the name of a Delphi enumerated type constant given its value.
function GetEnumName(TypeInfo: PTypeInfo; Value: Integer): string;
AnsiString GetEnumName(PTypeInfo TypeInfo, int Value);
Use GetEnumName to convert a Delphi enumerated value into the symbolic name that represents it in code.
TypeInfo is the type information record that describes the enumerated type. You can obtain the type information for a type by calling the TypeInfo function in Delphi or the __delphirtti operator in C++.
Value is the enumerated value, represented as an integer.
GetEnumName returns the string that represents the specified value.
C++ Examples:
/* Add the Delphi source file that appears on this Help page into a CPP Builder project that includes a CPP module containing the following code. An hpp file will be generated for the Delphi code when you build the project. Add the include line for that hpp file at the top of the CPP module. The FormCreates for both forms will execute and the following generics code will work. Remember to give the forms different names! */ void __fastcall TForm1::FormCreate(TObject *Sender) { // Prints type info for string type TGenericClass__1<System::UnicodeString> *GString = new TGenericClass__1<System::UnicodeString>(); GString->PrintTypeInfo(Memo1); // Prints type info for Byte type TGenericClass__1<Byte> *GByte = new TGenericClass__1<Byte>(); GByte->PrintTypeInfo(Memo1); // Prints type info for Double type TGenericClass__1<Double> *GDouble = new TGenericClass__1<Double>(); GDouble->PrintTypeInfo(Memo1); // Prints type info for "array of String" type // TGenericClass__1<array of string> *GStringArray = new TGenericClass__1<array of string>(); // GStringArray->PrintTypeInfo(Memo1); }
Delphi Examples:
{ This example demostrates the methods to retreive of Run-time Type Information (RTTI) information. This example will print useful information about any given type including it's name, size, kind and sub-kind. } type TForm2 = class(TForm) Memo1: TMemo; procedure FormCreate(Sender: TObject); private { Private declarations } public { Public declarations } end; { Defining a generic type that contains a single class (static) method that will print information about the type it operates on. } TGenericClass<T> = class(TList<T>) // TList is a class in Generics.Collections public procedure PrintTypeInfo(memo: TMemo); end; TGenericString = class(TGenericClass<UnicodeString>) end; TGenericByte = class(TGenericClass<Byte>) end; TGenericDouble = class(TGenericClass<Double>) end; var Form2: TForm2; implementation {$R *.dfm} { Method defintition } procedure TGenericClass<T>.PrintTypeInfo(memo: TMemo); var Info : PTypeInfo; Data : PTypeData; KindName : String; SubName : String; begin { Get type info for the "yet unknown type" } Info := System.TypeInfo(T); { There is no RTTI attached for some types like Records for example. } if Info <> nil then begin memo.Lines.Add('Type name: ' + Info^.Name); { Find out the name of an enum item from it's ordinal value } KindName := TypInfo.GetEnumName(System.TypeInfo(TTypeKind), Ord(Info^.Kind)); memo.Lines.Add('Type kind: ' + KindName); Data := GetTypeData(Info); if Info^.Kind = tkInteger then begin { In case of integer let's see the actual sub-type name } SubName := TypInfo.GetEnumName(System.TypeInfo(TOrdType), Ord(Data^.OrdType)); memo.Lines.Add('Integer kind: ' + SubName); end; if Info^.Kind = tkFloat then begin { In case of float let's see the actual sub-type name } SubName := TypInfo.GetEnumName(System.TypeInfo(TFloatType), Ord(Data^.FloatType)); memo.Lines.Add('Float kind: ' + SubName); end; if Info^.Kind = tkDynArray then begin { Let's check out the element size } memo.Lines.Add('Array element type name: ' + Data^.elType^^.Name); memo.Lines.Add('Array element type size: ' + IntToStr(Data^.elSize)); end; end; memo.Lines.Add('Size of type: ' + IntToStr(SizeOf(T))); end; procedure TForm2.FormCreate(Sender: TObject); var GenericString : TGenericClass<UnicodeString>; GenericByte : TGenericClass<Byte>; GenericDouble : TGenericClass<Double>; // GenericStringArray : TGenericClass<array of string>; begin { Prints type info for string type} GenericString := TGenericClass<UnicodeString>.Create; GenericString.PrintTypeInfo(Memo1); { Prints type info for Byte type} GenericByte := TGenericClass<Byte>.Create; GenericByte.PrintTypeInfo(Memo1); { Prints type info for Double type} GenericDouble := TGenericClass<Double>.Create; GenericDouble.PrintTypeInfo(Memo1); end; { Expected results are: Type name: string Type kind: tkUString Size of type: 4 Type name: Byte Type kind: tkInteger Integer kind: otUByte Size of type: 1 Type name: Double Type kind: tkFloat Float kind: ftDouble Size of type: 8 Type name: .1 Type kind: tkDynArray Array element type name: string Array element type size: 4 Size of type: 4 }
Copyright(C) 2009 Embarcadero Technologies, Inc. All Rights Reserved.
|
What do you think about this topic? Send feedback!
|