procedure TForm1.btn4Click(Sender: TObject);const  FieldName: array[1..3] of string = ('姓名','单位','地址');  FielValue: array[1..3] of string = ('张三','华为','广州');var  blockCount, FieldCount, i, j: Integer;  Doc, DocBlock, DocField: TDocVariantData;  v1, Data: variant;begin  Doc.Init;  Doc.I['blockCount'] := 3;  for i := 1 to 3 do  begin    DocBlock.Init;    DocBlock.I['FieldCount'] := i;    for j := 1 to i do    begin      DocField.Init;      V1 := _Json(WideStringToUTF8(Format('{"Name":"%s","Value":["%s","%s","%s"]}',          [            FieldName[j],  FielValue[j] + '_1', FielValue[j] + '_2', FielValue[j] + '_3'          ]      )));      DocBlock.A_['fields']^.AddItem(v1);      TDocVariantData(Data).InitJSON(DocBlock.ToJSON());    end;    doc.A_['blocks']^.AddItem(Data);  end;  mmo1.Lines.Text := UTF8ToWideString(doc.ToJSON);end;{"blockCount":3,"blocks":[   {"FieldCount":1,"fields":[{"Name":"姓名","Value":["张三_1","张三_2","张三_3"]}]},   {"FieldCount":2,"fields":[{"Name":"姓名","Value":["张三_1","张三_2","张三_3"]},{"Name":"单位","Value":["华为_1","华为_2","华为_3"]}]},   {"FieldCount":3,"fields":[{"Name":"姓名","Value":["张三_1","张三_2","张三_3"]},{"Name":"单位","Value":["华为_1","华为_2","华为_3"]},{"Name":"地址","Value":["广州_1","广州_2","广州_3"]}]}]}

uses SynCommons;

前面的写法有内存泄漏，下面是修改好的代码:

procedure TForm1.btn4Click(Sender: TObject);const  FieldName: array[1..3] of string = ('UserName','Department','Address');  FielValue: array[1..3] of string = ('Gets','Google','American');var  i, j: Integer;  Doc, DocBlock: TDocVariantData;  v1, Data: variant;begin  Doc.Init;  Doc.I['blockCount'] := 3;  for i := 1 to 3 do  begin    DocBlock.Init;    DocBlock.I['FieldCount'] := i;    for j := 1 to i do    begin      V1 := _Json(WideStringToUTF8(Format('{"Name":"%s","Value":["%s","%s","%s"]}',          [            FieldName[j],  FielValue[j] + '_1', FielValue[j] + '_2', FielValue[j] + '_3'          ]      )));      DocBlock.A_['fields']^.AddItem(v1);      VarClear(v1);    end;    TDocVariantData(Data).InitJSON(DocBlock.ToJSON());    doc.A_['blocks']^.AddItem(Data);    DocBlock.Clear;    FreeAndNil(DocBlock);    VarClear(Data);  end;  mmo1.Lines.Text := UTF8ToWideString(doc.ToJSON);  doc.Clear;  FreeAndNil(doc);end;