freepascal TJsonDataset

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unit Unit1;   {$mode objfpc}{$H+}   interface   uses   Classes, SysUtils, Forms, Controls, Graphics, Dialogs, DBCtrls, DBGrids, DB,   fpjson, fpjsondataset;   type     TForm1 = class(TForm)     DataSource1: TDataSource;     DBGrid1: TDBGrid;     procedure FormCreate(Sender: TObject);   private     JSONDataSet: TJSONDataSet;   end;   var   Form1: TForm1;   const   // this is the sample JSON data used in the demo   JSON_STRING = '['     +'{"Author ID":"409-56-7008","Last Name":"Bennet","First Name":"Abraham","Active": False},'     +'{"Author ID":"213-46-8915","Last Name":"Green","First Name":"Marjorie","Active": True}'     +']';   implementation   {$R *.lfm}   procedure TForm1.FormCreate(Sender: TObject); var   data: TJSONArray; begin   // parse the JSON string   data := GetJSON(JSON_STRING) as TJSONArray;   // create a new TJSONDataSet   JSONDataSet := TJSONDataSet.Create(Self);   // you'll need to create the FieldDefs manually   // ftString requires a length specified   JSONDataSet.FieldDefs.Add('Author ID', ftString, 11, True);   JSONDataSet.FieldDefs.Add('Last Name', ftString, 40);   JSONDataSet.FieldDefs.Add('First Name', ftString, 20);   JSONDataSet.FieldDefs.Add('Active', ftBoolean);   // set OwnsData to True, and the JSON data will be destroyed when the dataset is destroyed   JSONDataSet.OwnsData := True;   // the JSON data is an array of objects   JSONDataSet.RowType := rtJSONObject;   // assign the JSON data to the dataset   JSONDataSet.Rows := data;   // activate the dataset   JSONDataSet.Active := True;   // assign the dataset to the datasource   DataSource1.DataSet := JSONDataSet; end;   end.

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procedure TForm1.Button1Click(Sender: TObject); begin   JSONDataSet1.FieldDefs.Add('id', ftstring, 9);   JSONDataSet1.FieldDefs.Add('name', ftstring, 9);   JSONDataSet1.Open;   JSONDataSet1.Append;   JSONDataSet1['id'] := '1';   JSONDataSet1['name']:='中';   JSONDataSet1.Post;   memo1.Text:= JSONDataSet1.Rows.Clone.AsJSON;  //[{ "id" : "1", "name" : "中" }] end;