Question

你好我一直在网上关注一些我正在研究的新项目。我从文件流中获取数据，并且我在这一行得到了一个内存不足的例外：

byte[] buffer = new byte[(int)sfs.Length];

我正在做的是立即获取字节数组，然后将其保存到光盘。如果没有一种简单的方法可以避免系统内存异常，是否有办法从sqlFileStream写入光盘，避免创建新的字节数组？

        string cs = @”Data Source=<your server>;Initial Catalog=MyFsDb;Integrated Security=TRUE”;
        using (SqlConnection con = new SqlConnection(cs))
        {

            con.Open();
            SqlTransaction txn = con.BeginTransaction();
            string sql = “SELECT fData.PathName(), GET_FILESTREAM_TRANSACTION_CONTEXT(), fName FROM MyFsTable”;
            SqlCommand cmd = new SqlCommand(sql, con, txn);
            SqlDataReader rdr = cmd.ExecuteReader();
            while (rdr.Read())
            {
                string filePath = rdr[0].ToString();
                byte[] objContext = (byte[])rdr[1];
                string fName = rdr[2].ToString();

                SqlFileStream sfs = new SqlFileStream(filePath, objContext, System.IO.FileAccess.Read);

                **byte[] buffer = new byte[(int)sfs.Length];**
                sfs.Read(buffer, 0, buffer.Length);
                sfs.Close();


                string filename = @”C:\Temp\” + fName;

                System.IO.FileStream fs = new System.IO.FileStream(filename, FileMode.Create, FileAccess.Write, FileShare.Write);
                fs.Write(buffer, 0, buffer.Length);
                fs.Flush();
                fs.Close();
            }

            rdr.Close();
            txn.Commit();
            con.Close();
        }
    }

Answer 1

这是一种方法，可用于从一个Stream到另一个Stream读取字节，而不考虑它们各自的Stream类型。

Public Sub CopyStream(source As Stream, destination As Stream, Optional blockSize As Integer = 1024)
    Dim buffer(blockSize - 1) As Byte

    'Read the first block.'
    Dim bytesRead = source.Read(buffer, 0, blockSize)

    Do Until bytesRead = 0
        'Write the current block.'
        destination.Write(buffer, 0, bytesRead)

        'Read the next block.'
        bytesRead = source.Read(buffer, 0, blockSize)
    Loop
End Sub

从sqlFileStream保存到disc directyl或者弄清楚如何在一个字节数组中存储大数据

1 个答案: