咨询TADOConnection连接excel文件出现的问题我在一个form中放置了TADOConnection(假设其name为ADOCon)、TADODataSet(假设起name为ADODataSet1)、TDBGrid等控件,然后,将ADOCon的ConnectionString设置到一个excel文件;
将ADODataSet1的Connection设置为ADOCon;
将ADODataSet1的CommandText设置为excel文件的一个表,如Sheet1$;然后,在Button事件代码里有几句:
frmmain.ADOCon.Connected:=true; //第1句
frmmain.ADODataSet1.Active:=true; //第2句
frmmain.DBGrid1.ReadOnly:=true; //第3句第一次执行该代码段时,很正常,TDBGrid能正常显示excel文件Sheet1里的内容,
当第二次点击Button按钮时,执行到第2句就会提示excel文件的Sheet1表不存在不知为什么,怎么解决
将ADODataSet1的Connection设置为ADOCon;
将ADODataSet1的CommandText设置为excel文件的一个表,如Sheet1$;然后,在Button事件代码里有几句:
frmmain.ADOCon.Connected:=true; //第1句
frmmain.ADODataSet1.Active:=true; //第2句
frmmain.DBGrid1.ReadOnly:=true; //第3句第一次执行该代码段时,很正常,TDBGrid能正常显示excel文件Sheet1里的内容,
当第二次点击Button按钮时,执行到第2句就会提示excel文件的Sheet1表不存在不知为什么,怎么解决
将ADODataSet1的CommandText设置为excel文件的一个表,如Sheet1$,同时,将CommandType设置为cmdTableDirect;
在Open前面加一句ADODataSet1.Close;
该函数的功能:将数据库表的所有记录导出到EXCEL文件,速度非常快,大家可以拷回去用.我上面的问题中,在调用func1之前,Button事件代码(frmmain.ADODataSet1.Active:=true; //第2句 )能正常执行,当调用func1之后,Button事件代码(frmmain.ADODataSet1.Active:=true;)就过不去了,系统提示数据库引擎找不到表Sheet1$func1完整代码如下(是从网上下载的)
unit func1;interfaceUses
DB, Classes;var
CXlsBof: array[0..5] of Word = ($809, 8, 0, $10, 0, 0);
CXlsEof: array[0..1] of Word = ($0A, 00);
CXlsLabel: array[0..5] of Word = ($204, 0, 0, 0, 0, 0);
CXlsNumber: array[0..4] of Word = ($203, 14, 0, 0, 0);
CXlsRk: array[0..4] of Word = ($27E, 10, 0, 0, 0);
CXlsBlank: array[0..4] of Word = ($201, 6, 0, 0, $17);Type
TDS2Excel = Class(TObject)
Private
FCol: word;
FRow: word;
FDataSet: TDataSet;
Stream: TStream;
FWillWriteHead: boolean;
FBookMark: TBook;
procedure IncColRow;
procedure WriteBlankCell;
procedure WriteFloatCell(const AValue: Double);
procedure WriteIntegerCell(const AValue: Integer);
procedure WriteStringCell(const AValue: string);
procedure WritePrefix;
procedure WriteSuffix;
procedure WriteTitle;
procedure WriteDataCell;
procedure Save2Stream(aStream: TStream);
Public
procedure Save2File(FileName: string; WillWriteHead: Boolean);
Constructor Create(aDataSet: TDataSet);
end;implementationuses SysUtils;Constructor TDS2Excel.Create(aDataSet: TDataSet);
begin
inherited Create;
FDataSet := aDataSet;
end;procedure TDS2Excel.IncColRow;
begin
if FCol = FDataSet.FieldCount - 1 then
begin
Inc(FRow);
FCol :=0;
end
else
Inc(FCol);
end;procedure TDS2Excel.WriteBlankCell;
begin
CXlsBlank[2] := FRow;
CXlsBlank[3] := FCol;
Stream.WriteBuffer(CXlsBlank, SizeOf(CXlsBlank));
IncColRow;
end;procedure TDS2Excel.WriteFloatCell(const AValue: Double);
begin
CXlsNumber[2] := FRow;
CXlsNumber[3] := FCol;
Stream.WriteBuffer(CXlsNumber, SizeOf(CXlsNumber));
Stream.WriteBuffer(AValue, 8);
IncColRow;
end;procedure TDS2Excel.WriteIntegerCell(const AValue: Integer);
var
V: Integer;
begin
CXlsRk[2] := FRow;
CXlsRk[3] := FCol;
Stream.WriteBuffer(CXlsRk, SizeOf(CXlsRk));
V := (AValue shl 2) or 2;
Stream.WriteBuffer(V, 4);
IncColRow;
end;procedure TDS2Excel.WriteStringCell(const AValue: string);
var
L: Word;
begin
L := Length(AValue);
CXlsLabel[1] := 8 + L;
CXlsLabel[2] := FRow;
CXlsLabel[3] := FCol;
CXlsLabel[5] := L;
Stream.WriteBuffer(CXlsLabel, SizeOf(CXlsLabel));
Stream.WriteBuffer(Pointer(AValue)^, L);
IncColRow;
end;procedure TDS2Excel.WritePrefix;
begin
Stream.WriteBuffer(CXlsBof, SizeOf(CXlsBof));
end;procedure TDS2Excel.WriteSuffix;
begin
Stream.WriteBuffer(CXlsEof, SizeOf(CXlsEof));
end;procedure TDS2Excel.WriteTitle;
var
n: word;
begin
for n := 0 to FDataSet.FieldCount - 1 do
WriteStringCell(FDataSet.Fields[n].DisplayLabel);
end;procedure TDS2Excel.WriteDataCell;
var
n: word;
begin
WritePrefix;
if FWillWriteHead then WriteTitle;
FDataSet.DisableControls;
FBookMark := FDataSet.GetBook;
FDataSet.First;
while not FDataSet.Eof do
begin
for n := 0 to FDataSet.FieldCount - 1 do
begin
if FDataSet.Fields[n].IsNull then
WriteBlankCell
else begin
case FDataSet.Fields[n].DataType of
ftSmallint, ftInteger, ftWord, ftAutoInc, ftBytes:
WriteIntegerCell(FDataSet.Fields[n].AsInteger);
ftFloat, ftCurrency, ftBCD:
WriteFloatCell(FDataSet.Fields[n].AsFloat);
else
WriteStringCell(FDataSet.Fields[n].AsString);
end;
end;
end;
FDataSet.Next;
end;
WriteSuffix;
if FDataSet.BookValid(FBookMark) then FDataSet.GotoBook(FBookMark);
FDataSet.EnableControls;
end;procedure TDS2Excel.Save2Stream(aStream: TStream);
begin
FCol := 0;
FRow := 0;
Stream := aStream;
WriteDataCell;
end;procedure TDS2Excel.Save2File(FileName: string; WillWriteHead: Boolean);
var
aFileStream: TFileStream;
begin
FWillWriteHead := WillWriteHead;
if FileExists(FileName) then DeleteFile(FileName);
aFileStream := TFileStream.Create(FileName, fmCreate);
Try
Save2Stream(aFileStream);
Finally
aFileStream.Free;
end;
end;end.
调用方法:
(说明:TDS2Excel和Save2File是func1里定义的函数)
With TDS2Excel.Create(TDataSet(ADOQuery1)) do
Try
if SaveDialog1.Execute then
begin
Save2File(SaveDialog1.FileName, True);
showmessage('“客户资料”已经导出到电子表格!');
end
else
showmessage('您点击了取消按钮!');
finally
button7.Enabled:=false;
button8.Enabled:=false;
Free;
end;
except
showmessage('----保存失败!----');
end;