C# 从后台线程更新 Windows 窗体中的 UI

Question

http://www.codeproject.com/KB/threads/winformsthreading.aspx

我正在尝试使用上面的方法，虽然它在某种意义上起作用(它不会锁定我的应用程序)，但不幸的是它没有更新 UI 上的标签。我在某处出错了吗？我在 MainForm 上有两个标签，expiredPoliciesLabel 和 missingPoliciesLabel。要更新它们，我必须通过执行一系列数据库查询来设置 expiredPoliciesNum 和 missingPoliciesNum，如您所见。我需要标签每分钟左右自动更新一次。 (我知道现在我将它设置为 1 秒，这只是为了查看代码是否正常工作)

这是我的代码。

public delegate void updatePolicyLabelsDelegate();

public partial class MainForm: Form
{
    SQLiteQuery sqliteQuery = new SQLiteQuery(Properties.Settings.Default.DatabasePath);
    int expiredPoliciesNum = 0;
    int missingPoliciesNum = 0;
    Thread minimizeThread;

    public MainForm()
    {
        this.Resize += new EventHandler(MainForm_Resize);
        this.IsMdiContainer = true;
        InitializeComponent();
        this.ShowInTaskbar = false;

        keyValidation();

        Thread bottomLabelsThread = new Thread(new ThreadStart(updateLabels));
        bottomLabelsThread.IsBackground = true;
    }

    public void updateLabels()
    {
        while (true)
        {
            Invoke(new updatePolicyLabelsDelegate(updatePolicyLabels));
            Thread.Sleep(1000);
        }
    }

    private void updatePolicyLabels()
    {
        DataTable dt = sqliteQuery.selectFromDatabase("*", "WHERE GLOPolicy != '1'");
        missingPoliciesNum = dt.Rows.Count;

        dt = sqliteQuery.selectFromDatabase("*", "WHERE ALPolicy != '1'");
        missingPoliciesNum = missingPoliciesNum + dt.Rows.Count;

        dt = sqliteQuery.selectFromDatabase("*", "WHERE WCPolicy != '1'");
        missingPoliciesNum = missingPoliciesNum + dt.Rows.Count;

        dt = sqliteQuery.selectFromDatabase("*", "WHERE ULPolicy != '1'");
        missingPoliciesNum = missingPoliciesNum + dt.Rows.Count;

        String now = DateTime.Now.Year + "-" + DateTime.Now.Month + "-" + DateTime.Now.Day;

        dt = sqliteQuery.selectFromDatabase("*", "WHERE GLOPolicy = '1' AND GLOExpiration < '" + now + "'");
        expiredPoliciesNum = dt.Rows.Count;

        dt = sqliteQuery.selectFromDatabase("*", "WHERE ALPolicy = '1' AND ALExpiration < '" + now + "'");
        expiredPoliciesNum = expiredPoliciesNum + dt.Rows.Count;

        dt = sqliteQuery.selectFromDatabase("*", "WHERE WCPolicy = '1' AND WCExpiration < '" + now + "'");
        expiredPoliciesNum = expiredPoliciesNum + dt.Rows.Count;

        dt = sqliteQuery.selectFromDatabase("*", "WHERE ULPolicy = '1' AND ULExpiration < '" + now + "'");
        expiredPoliciesNum = expiredPoliciesNum + dt.Rows.Count;


        expiredPoliciesLabel.Text = expiredPoliciesNum + " Expired Policies       ";
        missingPoliciesLabel.Text = missingPoliciesNum + " Missing Policies       ";
    }

感谢您的帮助，我是线程的新手，可以使用一些专业知识，信不信由你，我到处搜索试图找出我出错的地方无济于事。

Answer 1

您创建了线程对象，但并未启动它，正如您的代码所显示的那样:

bottomLabelsThread.Start();

它不会自动启动。