Custom marshaling TDictionary in Delphi
I need to custom marshal/unmarchal a TDictionary in Delphi (XE). The dictionary is declared as:
T开发者_开发知识库MyRecord = record
key11: integer;
key12: string;
...
end;
TMyDict: TDictionary<string, TMyRecord>;
Now, if i marshal the dictionary without registering a custom converter, the marshaller will put all kind of fields in the JSON string - FOnValueNotify, FKeyCollection, FItems, etc.
What i need is some sort of associative array of associative arrays, i.e.
{"key1":{"key11":"val1","key12":"val2"},"key2":{"key11":"val3","key12":"val4"}}
Unfortunately, i don't know how to write the custom converter and reverter. I'm using Delphi XE and the built in TJSONMarshal and TJSONUnMarshal.
Note: The use of TDictionary for this task is not required. I just cant come with something better.
For a simple case like yours, I tend to use a custom method to represent my object in JSON. But, if you want to create reverter and converter, you should read this article: http://www.danieleteti.it/?p=146
Another option is TSuperObject which has the ability to marshal to/from JSON using RTTI:
type
TData = record
str: string;
int: Integer;
bool: Boolean;
flt: Double;
end;
var
ctx: TSuperRttiContext;
data: TData;
obj: ISuperObject;
begin
ctx := TSuperRttiContext.Create;
try
data := ctx.AsType<TData>(SO('{str: "foo", int: 123, bool: true, flt: 1.23}'));
obj := ctx.AsJson<TData>(data);
finally
ctx.Free;
end;
end;
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