Как создавать и редактировать xml-файлы?

{Unit to export a dataset to XML}
 
Unit DS2XML;
interface
uses Classes, DB;
Procedure DatasetToXML(Dataset: TDataSet; FileName: String);
 
implementation
uses SysUtils;
 
Var SourceBuffer:  PChar;
Procedure WriteString(Stream: TFileStream; s: String);
Begin
   StrPCopy(SourceBuffer, s);
   Stream.Write(SourceBuffer[0], StrLen(SourceBuffer));
End;
 
Procedure WriteFileBegin(Stream: TFileStream; Dataset: TDataSet);
Function XMLFieldType(fld: TField):  string;
Begin
   Case fld.DataType Of 
      ftString:  Result := '"string" WIDTH="' + IntToStr(fld.Size) + '"';
      ftSmallint:  Result := '"i4"';
 
      //?? ftInteger: Result := '"i4"';
      ftWord:  Result := '"i4"';
 
      //?? ftBoolean: Result := '"boolean"';
      ftAutoInc:  Result := '"i4" SUBTYPE="Autoinc"';
      ftFloat:  Result := '"r8"';
      ftCurrency:  Result := '"r8" SUBTYPE="Money"';
      ftBCD:  Result := '"r8"';
 
      //?? ftDate: Result := '"date"';
      ftTime:  Result := '"time"';
 
      //?? ftDateTime: Result := '"datetime"';
      Else
   End;
   If fld.Required Then Result := Result + ' required="true"';
   If fld.ReadOnly Then Result := Result + ' readonly="true"';
End;
 
Var i:  Integer;
Begin
   WriteString(Stream, '<?xml version="1.0" standalone="yes"?><!-- Generated by SMExport --> ' +
               '<DATAPACKET Version="2.0">');
   WriteString(Stream, '<METADATA><FIELDS>'); {write th metadata}
   With Dataset Do
      For i := 0 To FieldCount - 1 Do
      Begin
         WriteString(Stream, '<FIELD attrname="' + Fields[i].FieldName + '" fieldtype=' +
                     XMLFieldType(Fields[i]) + '/>');
      End;
   WriteString(Stream, '</FIELDS>');
   WriteString(Stream, '<PARAMS DEFAULT_ORDER="1" PRIMARY_KEY="1" LCID="1033"/>');
   WriteString(Stream, '</METADATA><ROWDATA>');
End;
Procedure WriteFileEnd(Stream: TFileStream);
Begin
   WriteString(Stream, '</ROWDATA></DATAPACKET>');
End;
Procedure WriteRowStart(Stream: TFileStream; IsAddedTitle: Boolean);
Begin
   If Not IsAddedTitle Then WriteString(Stream, '<ROW');
End;
Procedure WriteRowEnd(Stream: TFileStream; IsAddedTitle: Boolean);
Begin
   If Not IsAddedTitle Then WriteString(Stream, '/>');
End;
Procedure WriteData(Stream: TFileStream; fld: TField; AString: ShortString);
Begin
   If Assigned(fld) And (AString <> '') Then
      WriteString(Stream, ' ' + fld.FieldName + '="' + AString + '"');
End;
Function GetFieldStr(Field: TField):  string;
Function GetDig(i, j: Word):  string;
Begin
   Result := IntToStr(i);
   While (Length(Result) < j) Do
      Result := '0' + Result;
End;
 
Var Hour, Min, Sec, MSec:  Word;
Begin
   Case Field.DataType Of 
      ftBoolean:  Result := UpperCase(Field.AsString);
      ftDate:  Result := FormatDateTime('yyyymmdd', Field.AsDateTime);
      ftTime:  Result := FormatDateTime('hhnnss', Field.AsDateTime);
      ftDateTime:
      Begin
         Result := FormatDateTime('yyyymmdd', Field.AsDateTime);
         DecodeTime(Field.AsDateTime, Hour, Min, Sec, MSec);
         If (Hour <> 0) Or (Min <> 0) Or (Sec <> 0) Or (MSec <> 0) Then
            Result := Result + 'T' + GetDig(Hour, 2) + ':' + GetDig(Min, 2) +
            ':' + GetDig(Sec, 2) + GetDig(MSec, 3);
      End;
      Else Result := Field.AsString;
   End;
End;
Procedure DatasetToXML(Dataset: TDataSet; FileName: String);
 
Var Stream:  TFileStream;
   bkmark:  TBookmark;
   i:  Integer;
Begin
   Stream := TFileStream.Create(FileName, fmCreate);
   SourceBuffer := StrAlloc(1024);
   WriteFileBegin(Stream, Dataset);
   With DataSet Do
   Begin
      DisableControls;
      bkmark := GetBookmark;
      First; {write a title row}
      WriteRowStart(Stream, True);
      For i := 0 To FieldCount - 1 Do
         WriteData(Stream, Nil, Fields[i].DisplayLabel); {write the end of row}
      WriteRowEnd(Stream, True);
      While (Not EOF) Do
      Begin
         WriteRowStart(Stream, False);
         For i := 0 To FieldCount - 1 Do
            WriteData(Stream, Fields[i], GetFieldStr(Fields[i])); {write the end of row}
         WriteRowEnd(Stream, False);
         Next;
      End;
      GotoBookmark(bkmark);
      EnableControls;
   End;
   WriteFileEnd(Stream);
   Stream.Free;
   StrDispose(SourceBuffer);
End;
End.

//Beispiel, Example:
 
Uses DS2XML;
Procedure TForm1.Button1Click(Sender: TObject);
Begin
   DatasetToXML(Table1, 'test.xml');
End;