Question

我想将一些TStringStream连接成一个Stream。

我在SQL Server中有一些blob（varbinary（max））字段，我想从所有行创建一个流，然后将其保存到文件中。

ma[0,1:,None]

由于某些原因，这不能解决问题，任何人都可以帮我提出建议吗？如何连接我的Blob字段？

编辑：

在尝试David的解决方案之后

var
  // MSWord: Variant;
  i: Int32;
  sA: TStringStream;
  sP: TStringStream;
  s: TStringStream;
  // fString: TStrings;
begin
  sA := TStringStream.Create;
  s := TStringStream.Create;
  sP := TStringStream.Create;
  try
    with DateED do
    begin
      BlobField.SaveToStream(sA);
      sA.SaveToStream(s);
      // s.CopyFrom(sA, sA.Size);
      // s.LoadFromStream(sA);
      s.Position := sA.Size;
    end;
    with DateED.spED_TemplateParagraf do
    begin
      First;
      while not EOF do
      begin
        DateED.BlobField.SaveToStream(sP);
        sP.SaveToStream(s);
        s.Position := sP.Size;
        sP.Clear;
        Next;
      end;
    end;
    s.SaveToFile('D:\test.doc');
  finally
    sA.Free;
    s.Free;
    sP.Free;
  end;

我仍然无法从字段中找到所有信息

   procedure CopyBlobFieldToStream(ds: TDataSet; field: TBlobField; outputStream: TStream);
    var
      inputStream: TStream;
    begin
      inputStream := ds.CreateBlobStream(field, bmRead);
      try
        outputStream.CopyFrom(inputStream, inputStream.Size);
      finally
        inputStream.Free;
      end;
    end;

    ....

    stream := TFileStream.Create(fileName, fmCreate);
    try
      CopyBlobFieldToStream(ds, field1, stream);
      CopyBlobFieldToStream(ds, field2, stream);
    finally
      stream.Free;
    end;

这是我打电话的方式，但在Word Dock中我只找到第一个blob字段中的文本，但实际上流大小正在增加。

Answer 1

字符串流是作业的错误工具。你没有文字，你有二进制数据。您只是想连接两个二进制BLOB。用这些代码来做这件事：

procedure ConcatenateBlobField(ds: TDataSet; field1, field2: TBlobField; outputStream: TStream);
var
  inputStream: TStream;
begin
  inputStream := ds.CreateBlobStream(field1, bmRead);
  try
    outputStream.CopyFrom(inputStream, inputStream.Size);
  finally
    inputStream.Free;
  end;

  inputStream := ds.CreateBlobStream(field2, bmRead);
  try
    outputStream.CopyFrom(inputStream, inputStream.Size);
  finally
    inputStream.Free;
  end;
end;

要保存到文件，请创建TFileStream并将其传递给该函数。

stream := TFileStream.Create(fileName, fmCreate);
try
  ConcatenateBlobFields(ds, field1, field2, stream);
finally
  stream.Free;
end;

或者也许是这样：

procedure CopyBlobFieldToStream(ds: TDataSet; field: TBlobField; outputStream: TStream);
var
  inputStream: TStream;
begin
  inputStream := ds.CreateBlobStream(field, bmRead);
  try
    outputStream.CopyFrom(inputStream, inputStream.Size);
  finally
    inputStream.Free;
  end;
end;

....

stream := TFileStream.Create(fileName, fmCreate);
try
  CopyBlobFieldToStream(ds, field1, stream);
  CopyBlobFieldToStream(ds, field2, stream);
finally
  stream.Free;
end;

连接TStringStream

1 个答案: