如何从SQL Server中选择数据并将其保存到计算机上的某个位置 [英] How to select data from SQL Server and save it to somewhere on my computer

问题描述

我已经从数据库中选择了二进制数据，然后我展示了一个SaveFileDialog来将二进制数据保存在我的计算机上。我编写了以下代码来做到这一点，但是当我打开保存的文件时，其中没有任何数据。它只是对txt文件正常工作。我明白问题在于以下几行：

I've selected binary data by its name from database then I showed a SaveFileDialog to save that binary data somewhere on my computer. I wrote the following code to do that but when I opened saved file, there is not any data in it.It just work correctly for txt file. I understood that the problem is in following line:

byte[] content = sdr["Content"] as byte[];

在任意大小的文件的下一行它只能读取200byte。例如我上传了文件367byte，它正确上传，但是当我下载它时，在下面的行中，内容是200byte。

IN following line for any size of file it just can read 200byte of it .for example i uploaded the file with 367byte, It uploaded correctly but when i downloaded it, in follwing line, content is 200byte.

private void btnDownload_Click(object sender, EventArgs e)
     {
          try
         {
                    using (SqlCommand cmd = new SqlCommand("SelectFile", Conn))
                 {
                     cmd.CommandType = CommandType.StoredProcedure;
                     Conn.Open();
                     cmd.Parameters.Add("@FileName", SqlDbType.VarChar).Value = "1.txt";
                     string Ext = Path.GetExtension("1.txt");
                     SqlDataReader sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                     if (sdr.HasRows)
                     {
                         sdr.Read();
                         byte[] content =  sdr["Content"] as byte[] ;
                         if (fdDownload.ShowDialog() == DialogResult.OK)
                         {
                             FileStream fs = new FileStream(fdDownload.FileName + Ext  , FileMode.CreateNew, FileAccess.Write);
                         fs.Write(content, 0, content.Length);
                         fs.Flush();
                         fs.Close();
                         }
                         lblMessage.ForeColor = System.Drawing.Color.Green;
                         lblMessage.Text = "File  Downloaded Successfully";
                         Conn.Close();
                     }
                     else
                     {
                         lblMessage.ForeColor = System.Drawing.Color.Green;
                         lblMessage.Text = "File  not Downloaded Successfully";
                         Conn.Close();
                     }
                 }


         }
         catch (SqlException sqlEx)
         {
             lblMessage.ForeColor = System.Drawing.Color.Red;
             lblMessage.Text = "File not  Downloaded Successfully";
         }

     }

推荐答案

你好朋友，

请访问以下文章，因为这可能对您的要求有所帮助：



在ASP.NET中使用SQL Server上载和下载文件 [ ^ ]



- DD

Hello friend,
please visit the following article as this may be helpful to your requirement:

Upload and Download Files with SQL Server in ASP.NET[^]

- DD

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