c# - 如何在 C# 中的后台线程上执行异步数据库调用

Question

我正在处理一些数据库代码。在某些时候，我确实需要将这些调用从 UI 线程移到后台线程。我已经在下面发布了我的代码，但我很好奇一些这样做的例子，或者是否有人可以展示如何做到这一点。我在 Java 中完成了异步调用，只是想全神贯注地使用 Visual Studio 2013 执行此 C#。任何帮助将不胜感激。

数据库代码:

    static public Project.Project QueryProject(string projDatabaseName)
    {
        Project.Project proj = new Project.Project();
        string connStr = "server=localhost;database=" + projDatabaseName + ";user=******;port=3306;password=*****;";
        string queryStr = "SELECT * FROM " + projDatabaseName + ".project";
        MySqlConnection myConnection = new MySqlConnection(connStr);
        MySqlCommand myCommand = new MySqlCommand(queryStr, myConnection);
        myConnection.Open();

        try
        {
            MySqlDataReader myReader = myCommand.ExecuteReader();
            while (myReader.Read())
            {
                proj.ProjectID = int.Parse(myReader["ProjectID"].ToString());
                proj.ProjectName = myReader["ProjectName"].ToString();
                proj.ProjectStartDate = Convert.ToDateTime(myReader["ProjectStartDate"]);
                proj.ProjectEndDate = Convert.ToDateTime(myReader["ProjectEndDate"]);
                proj.ProjectNotes = myReader["ProjectNotes"].ToString();
            }
            myReader.Close();

        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
            return null;
        }
        finally
        {
            myConnection.Close();
        }
        return proj;
    }

调用数据库代码:

savedProj = ProjectDbInteraction.QueryProject(currentProjDb);

Answer 1

您应该对 BackgroundWorker 做一些研究 https://msdn.microsoft.com/en-us/library/system.componentmodel.backgroundworker%28v=vs.110%29.aspx以及一般使用 C# 的线程。

我会尝试使用看起来像这样的后台 worker :

//setting up your background worker.
var worker = new BackgroundWorker();
worker.DoWork += bgw_DoWork;
worker.RunWorkerCompleted += bgw_WorkCompleted;
worker.ProgressChanged += bgw_ProgressChanged;

private void bgw_DoWork(object sender, DoWorkEventArgs e)
{   
    e.Result = ProjectDbInteraction.QueryProject(currentProjDb);
}

private void bgw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
    //Here you can inspect the worker and update UI if needed.
}

private void bgw_WorkCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    //check for errors, and other unexpected results first...
    //assuming that savedProj is some private member variable of your class, 
    //just assign the variable to the Result here.
    savedProj = (Project.Project)e.Result;
}