在开发数据库应用程序中，经常要将类型相同的数据导出来，放到Excel文件中，利用Excel强大的编辑功能，对数据作进一步的加工处理。这有许多的方法，我们可以使用OLE技术，在Delphi中创建一个自动化对象，通过该对象来传送数据。也可以使用ADO，通过与Excel数据存储建立连接，使用ADO这种独立于数据库后端的技术来导出数据集的数据。
可这两种技术都有一个共同的缺点，那就是慢，数据量少还好，用户不会有太多的感觉，可一旦数据量大，比如，超过1千条，速度就让人难以忍受了，那么有没有更好的办法，既可以快速地导出数据，又不用安装附加的软件。也许好多人都想到了剪贴板的方式，这种方式速度是快，可也有不好的一面，那就是数据量大占用内存也大，并且在Excel中调用PASTE方法时，需要锁定输入，这使用起来，就有点不方便了
这里我为大家介始一种比较好的方法，使用文件流的方式，通过TfileStream直接写入Excel文件。我写了一个函数，通过它可将数据集中的数据直接导入到Excel文件中。我测试了一下，1M的数据，不到十秒就完成了。附源程序。
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs,DB, ADODB, Grids, DBGrids, StdCtrls;
type
TForm1 = class(TForm)
DBGrid1: TDBGrid;
ADOTable1: TADOTable;
DataSource1: TDataSource;
ADOConnection1: TADOConnection;
ADOTable1record_id: TIntegerField;
ADOTable1action_id: TIntegerField;
ADOTable1action_name: TStringField;
ADOTable1net_name: TStringField;
ADOTable1deal_no: TStringField;
ADOTable1name: TStringField;
ADOTable1getno_date: TDateTimeField;
ADOTable1window_no: TIntegerField;
ADOTable1staff_id: TStringField;
ADOTable1staff_name: TStringField;
ADOTable1deal_date: TDateTimeField;
ADOTable1deal_type: TStringField;
ADOTable1finish_date: TDateTimeField;
ADOTable1state: TStringField;
ADOTable1appraise: TStringField;
ADOTable1appraised_flag: TBooleanField;
ADOTable1cancel_led_time: TDateTimeField;
ADOTable1wait_time: TBCDField;
ADOTable1wait_time2: TStringField;
ADOTable1accept_time: TBCDField;
ADOTable1accept_time2: TStringField;
ADOTable1getnumber_addr: TIntegerField;
ADOTable1cust_level: TIntegerField;
ADOTable1cust_level_name: TStringField;
ADOTable1cust_level_name_remark: TStringField;
ADOTable1operation_sum: TIntegerField;
Button1: TButton;
SaveDialog1: TSaveDialog;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
arXlsBegin: array[0..5] of Word = ($809, 8, 0, $10, 0, 0);
arXlsEnd: array[0..1] of Word = ($0A, 00);
arXlsString: array[0..5] of Word = ($204, 0, 0, 0, 0, 0);
arXlsNumber: array[0..4] of Word = ($203, 14, 0, 0, 0);
arXlsInteger: array[0..4] of Word = ($27E, 10, 0, 0, 0);
arXlsBlank: array[0..4] of Word = ($201, 6, 0, 0, $17);
implementation
{$R *.dfm}
Procedure ExportExcelFile(FileName: string; bWriteTitle: Boolean; aDataSet: TDataSet);
var
i, j: integer;
Col, row: word;
ABookMark: TBookMark;
aFileStream: TFileStream;
procedure incColRow; //增加行列号
begin
if Col = ADataSet.FieldCount - 1 then
begin
Inc(Row);
Col :=0;
end
else
Inc(Col);
end;
procedure WriteStringCell(AValue: string);//写字符串数据
var
L: Word;
begin
L := Length(AValue);
arXlsString[1] := 8 + L;
arXlsString[2] := Row;
arXlsString[3] := Col;
arXlsString[5] := L;
aFileStream.WriteBuffer(arXlsString, SizeOf(arXlsString));
aFileStream.WriteBuffer(Pointer(AValue)^, L);
IncColRow;
end;
procedure WriteIntegerCell(AValue: integer);//写整数
var
V: Integer;
begin
arXlsInteger[2] := Row;
arXlsInteger[3] := Col;
aFileStream.WriteBuffer(arXlsInteger, SizeOf(arXlsInteger));
V := (AValue shl 2) or 2;
aFileStream.WriteBuffer(V, 4);
IncColRow;
end;
procedure WriteFloatCell(AValue: double);//写浮点数
begin
arXlsNumber[2] := Row;
arXlsNumber[3] := Col;
aFileStream.WriteBuffer(arXlsNumber, SizeOf(arXlsNumber));
aFileStream.WriteBuffer(AValue, 8);
IncColRow;
end;
begin
if FileExists(FileName) then
DeleteFile(FileName); //文件存在，先删除
aFileStream := TFileStream.Create(FileName, fmCreate);
Try
//写文件头
aFileStream.WriteBuffer(arXlsBegin, SizeOf(arXlsBegin));
//写列头
Col := 0; Row := 0;
if bWriteTitle then
begin
for i := 0 to aDataSet.FieldCount - 1 do
WriteStringCell(aDataSet.Fields[i].FieldName);
end;
//写数据集中的数据
aDataSet.DisableControls;
ABookMark := aDataSet.GetBookmark;
aDataSet.First;
while not aDataSet.Eof do
begin
for i := 0 to aDataSet.FieldCount - 1 do
case ADataSet.Fields[i].DataType of
ftSmallint, ftInteger, ftWord, ftAutoInc, ftBytes:
WriteIntegerCell(aDataSet.Fields[i].AsInteger);
ftFloat, ftCurrency, ftBCD:
WriteFloatCell(aDataSet.Fields[i].AsFloat)
else
WriteStringCell(aDataSet.Fields[i].AsString);
end;
aDataSet.Next;
end;
//写文件尾
AFileStream.WriteBuffer(arXlsEnd, SizeOf(arXlsEnd));
if ADataSet.BookmarkValid(ABookMark) then
aDataSet.GotoBookmark(ABookMark);
finally
AFileStream.Free;
ADataSet.EnableControls;
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
if SaveDialog1.Execute then
begin
ExportExcelFile(SaveDialog1.FileName,True,DBGrid1.DataSource.DataSet);
end;
end;
end.
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