高手请进,一个简单的问题

Question

求ClientDataSet存为二进制格式文件的文件格式。如何自己写代码生成相同的格式（不使用SaveToFile等）。

Answer 1

很遗憾
这个  
  SaveToStream
  SaveToFile
都不是虚函数。

Answer 2

原来写的一个，不整理了，VariantIn是自己打的一个包，也可不打包，直接把这几个TTable按你自己定义的格式存在文本去，到时再解析出来就好了，（要做些修改）Function varPack(var VariantPack: Variant;MasterInfo:RJbDjMainTableInfo;PriMemData:TdxMemData;strTalbeName:String):Integer;overload;
var
  pMasterFlds:array of string;
  pMasterTypes:array of string;
  pMasterValues:array of variant;
  i:Integer;
begin
  VariantPack:=VarArrayCreate([0,3],varVariant);
  setlength(pMasterFlds,Length(MasterInfo));
  setlength(pMasterTypes,Length(MasterInfo));
  setlength(pMasterValues,Length(MasterInfo));
  for i:=low(MasterInfo) to high(MasterInfo) do
  begin
    pMasterFlds[i]:=MasterInfo[i].strFldName;
    pMasterTypes[i]:=MasterInfo[i].strFldType;
    pMasterValues[i]:=PriMemData.FieldByName(MasterInfo[i].strFldName).Value;
  end;
  VariantPack[0]:=strTalbeName;
  VariantPack[1]:=pMasterFlds;
  VariantPack[2]:=pMasterTypes;
  VariantPack[3]:=pMasterValues;
end;Function varPack(var VariantPack: Variant;DetailInfo:RJbDjMxTableInfo;PriMemData:TdxMemData;MainMemData:TdxMemData;strTalbeName:String;strPkFld:String;strPkValue:String):Integer;overload;
var
  pDetailFlds:array of string;
  pDetailTypes:array of string;
  pDetailValues:array of variant;
  pDetailValue:array of variant;
  i,j,k:integer;
begin
  //明细数据
  k:=0;
  for j:=low(DetailInfo) to high(DetailInfo) do
  begin
    if DetailInfo[j].intFldKind<>0 then
      Continue;
    Inc(k);
  end;
  VariantPack:=VarArrayCreate([0,3],varVariant);
  setlength(pDetailFlds,k);
  setlength(pDetailTypes,k);
  k:=0;
  for j:=low(DetailInfo) to high(DetailInfo) do
  begin
    if DetailInfo[j].intFldKind<>0 then
      Continue;
    pDetailFlds[k]:=DetailInfo[j].strFldName;
    pDetailTypes[k]:=DetailInfo[j].strFldType;
    Inc(k);
  end;
  pDetailValues:=nil;
  PriMemData.First;
  setlength(pDetailValues,PriMemData.RecordCount);
  for i:=0 to PriMemData.RecordCount-1 do
  begin
    setlength(pDetailValue,Length(pDetailFlds));
    for j:=low(pDetailFlds) to high(pDetailFlds) do
    begin
      pDetailValue[j]:=PriMemData.FieldByName(pDetailFlds[j]).Value;
      if pDetailFlds[j]=strPkFld then
        pDetailValue[j]:=MainMemData.FieldByName(strPkFld).AsString;
    end;
    pDetailValues[i]:=pDetailValue;
    PriMemData.Next;
  end;
  VariantPack[0]:=strTalbeName;
  VariantPack[1]:=pDetailFlds;
  VariantPack[2]:=pDetailTypes;
  VariantPack[3]:=pDetailValues;
end;Function SaveDataPack(const VariantIn:Variant;const Filter:String):Integer;
var
  FileName:String;
  F:TextFile;
  i,j,k:Integer;
  MasterArr,FieldNameArr,FieldTypeArr,FieldValueArr,FieldValueDetailArr:Array of variant;
  FieldNameStr,FieldTypeStr,FieldValueStr:String;
  SaveDialogDataPack:TSaveDialog;
  DetailRecordCount:Integer;
  CurFilter:String;
  procedure SavePack(FileLabel:String;VariantRec:Variant);
  var
    j,k:Integer;
  begin
    FieldNameStr:='';
    FieldNameArr:=nil;
    FieldNameArr:=VariantRec[1];
    FieldTypeStr:='';
    FieldTypeArr:=nil;
    FieldTypeArr:=VariantRec[2];
    FieldValueArr:=nil;
    FieldValueArr:=VariantRec[3];
    if VarType(FieldValueArr[0])<>varEmpty then
      DetailRecordCount:=Length(FieldValueArr)
    else
      DetailRecordCount:=0;
    Writeln(F,FileLabel+SPLIT);
    Writeln(F,VarToStr(VariantRec[0])+SPLIT+IntToStr(Length(FieldNameArr))+SPLIT+IntToStr(DetailRecordCount)+SPLIT);
    for j:=low(FieldNameArr) to High(FieldNameArr) do
    begin
      FieldNameStr:=FieldNameStr+VarToStr(FieldNameArr[j])+SPLIT;
      FieldTypeStr:=FieldTypeStr+VarToStr(FieldTypeArr[j])+SPLIT;
    end;
    Writeln(F,FieldNameStr);
    Writeln(F,FieldTypeStr);
    if VarType(FieldValueArr[0])=varEmpty then
      Exit;
    for j:=low(FieldValueArr) to high(FieldValueArr) do
    begin
      FieldValueStr:='';
      FieldValueDetailArr:=nil;
      FieldValueDetailArr:=FieldValueArr[j];
      for k:=low(FieldValueDetailArr) to high(FieldValueDetailArr) do
      begin
        FieldValueStr:=FieldValueStr+VarToStr(FieldValueDetailArr[k])+SPLIT;
      end;
      Writeln(F,FieldValueStr);
    end;
  end;
begin
  Result:=0;
  SaveDialogDataPack:=TSaveDialog.Create(nil);
  CurFilter:='*.'+Filter+'|*.'+Filter;
  SaveDialogDataPack.Filter:=CurFilter;
  SaveDialogDataPack.FileName:=VariantIn[0][1]+'.'+Filter;
  if (SaveDialogDataPack.Execute) and (Trim(SaveDialogDataPack.FileName)<>'') then
  begin
    FileName:=SaveDialogDataPack.FileName;
    if Pos(Filter,FileName)=0 then
      FileName:=FileName+'.'+Filter;
  end
  else begin
    SaveDialogDataPack.Free;
    Result:=0;
    Exit;
  end;
  try
    AssignFile(F,FileName);
    Rewrite(F);
    Writeln(F,'单据编号'+SPLIT);
    Writeln(F,VarToStr(VariantIn[0][0])+SPLIT+VarToStr(VariantIn[0][1])+SPLIT);
    Writeln(F,'主表数据'+SPLIT);
    MasterArr:=VariantIn[1];
    FieldNameStr:='';
    FieldNameArr:=nil;
    FieldNameArr:=MasterArr[1];
    FieldTypeStr:='';
    FieldTypeArr:=nil;
    FieldTypeArr:=MasterArr[2];
    FieldValueStr:='';
    FieldValueArr:=nil;
    FieldValueArr:=MasterArr[3];
    Writeln(F,VarToStr(MasterArr[0])+SPLIT+IntToStr(Length(FieldNameArr))+SPLIT);
    for i:=low(FieldNameArr) to high(FieldNameArr) do
    begin
      FieldNameStr:=FieldNameStr+VarToStr(FieldNameArr[i])+SPLIT;
      FieldTypeStr:=FieldTypeStr+VarToStr(FieldTypeArr[i])+SPLIT;
      FieldValueStr:=FieldValueStr+VarToStr(FieldValueArr[i])+SPLIT;
    end;
    Writeln(F,FieldNameStr);
    Writeln(F,FieldTypeStr);
    Writeln(F,FieldValueStr);    Writeln(F,'明细数据'+SPLIT);
    Writeln(F,VarToStr(VariantIn[2])+SPLIT);
    MasterArr:=nil;
    MasterArr:=VariantIn;
    for i:=0 to VariantIn[2]-1 do
      SavePack('明细数据'+IntToStr(i),VariantIn[3+i]);
    {if VariantIn[2]>1 then
      SavePack('配码数据',VariantIn[2+VariantIn[2]-1]);
    if VariantIn[2]>2 then
      SavePack('装箱数据',VariantIn[2+VariantIn[2]]); }
  except
    Result:=-1;
    ShowMessage('另存异常！');
  end;
  CloseFile(F);
  SaveDialogDataPack.Free;
end;

Answer 3

是要写成和ClientDataSet生成的文件一样的格式，不是自已定义格式。
经过一晚上地研究，终于搞清楚了它的格式。
感谢 leejiey(李杰) 贴了这么多代码，需要自定义格式时值得学习。