生成文件并直接输出下载

string fileName = "";

fileName = DateTime.Now.ToFileTime() + ".csv";

MemoryStream memory = new MemoryStream();
StreamWriter writer = new StreamWriter(memory, System.Text.Encoding.GetEncoding("GB2312"));

string title = "内容";
writer.WriteLine(title);

writer.Flush();
          
Response.Clear();
Response.ClearHeaders();
Response.Buffer = true;
Response.ContentType = "application/csv";
Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
Response.BinaryWrite(memory.ToArray());

Response.End();