“Left side cannot be assigned to” for record type properties in Delphi

Question

I\'m curious to know why Delphi treats record type properties as read only:

  TRec = record
    A : integer;
    B : string;
  end;

  TForm1 = class(TForm)
         


        

Answer 1

This is because property are actually complied as a function. Properties only return or set a value. It is not a reference or a pointer to the record

so :

Testing.TestRecord.I := 10;  // error

is same as calling a function like this:

Testing.getTestRecord().I := 10;   //error (i think)

what you can do is:

r := Testing.TestRecord;    // read
r.I := 10;
Testing.TestRecord := r;    //write

It is a bit messy but inherent in this type of architecture.