Question

In Delphi 2007, I added a new string type to my project:

type   String40 = string; 

This property is used in a class:

type   TPerson = class   private     FFirstName = String40;   published     FirstName: string40 read FFirstName write FFirstName;   end; 

During runtime, I want to get the name of the property FirstName by using RTTI. I expect it to be String40:

var   MyPropInfo: TPropInfo;   PropTypeName: string;   MyPerson: TPerson; begin   MyPerson := TPerson.Create;   MyPropInfo := GetPropInfo(MyPerson, 'FirstName')^;   PropTypeName := MyPropInfo.PropType^.Name; 

However, in this example PropTypeName is ‘string’. What do I need to do get the correct property type name, ‘String40’?

Answer 1

This works in Delphi5

type   String40 = type string; 

As for the rest of your code, to have RTTI available you should

• inherit TPerson from TPersistent or
• use the {$M+} compiler directive for TPerson
• make the Firstname property published

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Edit: what happens if you compile and run this piece of code?

program Project1;  uses   Classes,   typInfo,   Dialogs,   Forms;  {$R *.RES}  type   String40 = type string;   TPerson = class(TPersistent)   private     FFirstName: String40;   published     property FirstName: string40 read FFirstName write FFirstName;   end;  var   MyPropInfo: TPropInfo;   PropTypeName: string;   MyPerson: TPerson;  begin   Application.Initialize;   MyPerson := TPerson.Create;   MyPropInfo := GetPropInfo(MyPerson, 'FirstName')^;   PropTypeName := MyPropInfo.PropType^.Name;   ShowMessage(PropTypeName); end.