如何使用asp.net核心从数据库中的特定行下载图像

Posted 2023-04-13

【中文标题】如何使用asp.net核心从数据库中的特定行下载图像

【英文标题】：How to download an image from specific row from database with asp.net core

【发布时间】：2021-11-28 23:04:33

【问题描述】：

我想从数据库中获取图像并在我的 react-native 应用程序中显示它。我哪里出错了？

public IActionResult DownloadFile(int id)

    DataTable table = new DataTable();
    string query = @"select image from mydb.courses where id=@id";
    string sqlDataSource = _configuration.GetConnectionString("UsersAppCon");
    mysqlDataReader myReader;
    using (MySqlConnection mycon = new MySqlConnection(sqlDataSource))
    
        mycon.Open();
        using (MySqlCommand myCommand = new MySqlCommand(query, mycon))
        
            myReader = myCommand.ExecuteReader();
            table.Load(myReader);
            var fs = new FileStream(myReader, FileMode.Open);
            return File(fs, "application/octet-stream");
            myReader.Close();
            mycon.Close();
        
    

【问题讨论】：

return 将阻止close() 被调用。要返回图像，请查看：***.com/questions/39177576/…

嗨@Ali Mahmoudi，错误信息是什么？你能分享你的反应组件吗？

嗨，格雷格和@Rena，我修好了

【参考方案1】：

我修好了。

[HttpGet("id")]
public IActionResult DownloadFile(int id)

    string pathImage = "";
    DataTable table = new DataTable();
    string query = @"select image from mydb.courses where id=@id";
    string sqlDataSource = _configuration.GetConnectionString("UsersAppCon");
    MySqlDataReader myReader;
    using (MySqlConnection mycon = new MySqlConnection(sqlDataSource))
    
        mycon.Open();
        using (MySqlCommand myCommand = new MySqlCommand(query, mycon))
        
            myCommand.Parameters.AddWithValue("@id", id);
            pathImage = (string)myCommand.ExecuteScalar();
            mycon.Close();
        
    
    var path = @$"pathImage";
    var fs = new FileStream(path, FileMode.Open);
    return File(fs, "image/jpeg");