我将如何从背景工作者中填充列表框？

Question

我在从后台工作人员线程填充列表框时遇到麻烦。我目前有以下代码：

    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        var lockedUsers = new List<UserPrincipal>();
        using (var context = new PrincipalContext(ContextType.Domain, "domain", smtu, smtp))
        {
            GroupPrincipal grp = GroupPrincipal.FindByIdentity(context, IdentityType.SamAccountName, "Domain Users");
            foreach (var userPrincipal in grp.GetMembers(false))
            {

                var user = UserPrincipal.FindByIdentity(context, IdentityType.SamAccountName, userPrincipal.SamAccountName);
                if (user != null)
                {
                    if (user.IsAccountLockedOut())
                    {
                        listBox1.Items.Add(@"domain\ " + user);
                    }
                }
            }
        }
    }

这将返回异常，说我无法写入主UI，这是正确的。但是我一直无法找到解决方法。我尝试了以下操作，尽管它没有出现任何错误，但没有填充列表框。

    List<string> listusers = new List<string>();


    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        var lockedUsers = new List<UserPrincipal>();
        using (var context = new PrincipalContext(ContextType.Domain, "domain", smtu, smtp))
        {
            GroupPrincipal grp = GroupPrincipal.FindByIdentity(context, IdentityType.SamAccountName, "Domain Users");
            foreach (var userPrincipal in grp.GetMembers(false))
            {

                var user = UserPrincipal.FindByIdentity(context, IdentityType.SamAccountName, userPrincipal.SamAccountName);
                if (user != null)
                {
                    if (user.IsAccountLockedOut())
                    {
                        listusers.Add(@"domain\" + user);
                    }
                }
            }
        }
    }

    private async void timerlocked_Tick(object sender, EventArgs e)
    {
        backgroundWorker1.RunWorkerAsync();
        listBox1.DataSource = listusers;
    }

有什么想法吗？

Answer 1

传递给DoWorkEventArgs委托的DoWorkEventHandler具有Result property

获取或设置一个表示异步操作结果的值。

您设置的Result将通过传递给该委托的Result发送到RunWorkerCompleted事件。

因此，要解决此问题，您可以在RunWorkerCompletedEventArgs事件内部构建List<string>，将DoWork属性设置为该列表，处理Result事件并从RunWorkerCompleted访问该列表。] >

RunWorkerCompletedEventArgs.Result

Answer 2

[要从后台工作程序访问UI线程，您可以在

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
    var result = new List<string>();
    var lockedUsers = new List<UserPrincipal>();
    using (var context = new PrincipalContext(ContextType.Domain, "domain", smtu, smtp))
    {
        GroupPrincipal grp = GroupPrincipal.FindByIdentity(context, IdentityType.SamAccountName, "Domain Users");
        foreach (var userPrincipal in grp.GetMembers(false))
        {

            var user = UserPrincipal.FindByIdentity(context, IdentityType.SamAccountName, userPrincipal.SamAccountName);
            if (user != null)
            {
                if (user.IsAccountLockedOut())
                {
                    result.Add(@"domain\ " + user);
                }
            }
        }
    }
    e.Result = result;
}

private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    if (e.Error != null)
    {
        // Error handling.
    }
    if (e.Cancelled)
    {
       // If you support cancellation...
    }
    listBox1.Items.Clear();
    listBox1.Items.AddRange((e.Result as List<string>).ToArray());
}

的RunWorkerCompleted事件中进行工作，或者-如果您想在工作程序运行时访问UI，请查看[C0 ]。