blob字段如何存取？

Question

blob字段如何存取？
吾知为什么我DELPHI中不能用TBlobStream?

Answer 1

1.保存
var
      vTreeStream : TADOBlobStream;
      vSql : String;
begin
      //(1)如果使用的是TTable,则要将其ReadOnly属性先置为false,然后调用Edit函数;
      //(2)如果使用的是TQuery,则要将其RequestLive属性先置为true,然后调用Edit函数;
      ADOTable1.Active := True;
      ADOTable1.Edit;//必须为Edit状态
      vTreeStream := TADOBlobStream.Create(TBlobField(ADOTable1.FieldByName('字段名')), bmWrite);
      vTreeStream.Seek(0, soFromBeginning);
      vTreeStream.Truncate;
      TreeLB.SaveToStream(vTreeSTream);
      vTreeStream.Free;
      ADOTable1.Post;
end;2.读取
var
      vTreeStream : TADOBlobStream;
begin
      if ADOTable1.Active then ADOTable1.Active := False;
      ADOTable1.Open;
      vTreeStream := TADOBlobStream.Create(TBlobField(ADOTable1.FieldByName('字段名')), bmRead);
      vTreeStream.Seek(0, soFromBeginning);
      TreeLB.LoadFromStream(vTreeStream);//
      vTreeStream.Free;
      ADOTable1.Close;
end;

Answer 2

procedure TForm1.Button1Click(Sender: TObject);
var FileStream:TFileStream;
begin
    FileStream:=TFileStream.Create('C:\ExcelName.XLS',fmOpenRead);
    //如果文件被占用可以更改fmOpenRead
    Try
       Table.Edit;
       MyBlobFile.LoadFromStream(FileStream)
       Table.Post;
    Finally
       FileStream.Free;
    End;
end;或者
       Table.Edit;
       MyBlobFile.LoadFromFile('C:\ExcelName.XLS')
       Table.Post;

Answer 3

FileStream:=TFileStream.Create(文件可以是任何文件类型,fmOpenRead);
MyBlobFile.LoadFromFile(文件可以是任何文件类型)