在控件焦点上打开WPF中的AutoCompleteBox

Question

我正试图打开System.Windows.Controls.AutoCompleteBox控制焦点.事件触发但没有任何反应:/当我开始输入一些文本时,自动完成框工作正常.我究竟做错了什么？

AutoCompleteBox box = new AutoCompleteBox();
box.Text = textField.Value ?? "";
box.ItemsSource = textField.Proposals;
box.FilterMode = AutoCompleteFilterMode.Contains;
box.GotFocus += (sender, args) =>
    {
        box.IsDropDownOpen = true;
    };

Answer 1

我做了一个快速的解决方法,好像这个解决方案在我的程序中对我来说很满意.

AutoCompleteBox box = new AutoCompleteBox();
box.Text = textField.Value ?? "";
if (textField.Proposals != null)
{
    box.ItemsSource = textField.Proposals;
    box.FilterMode = AutoCompleteFilterMode.None;
    box.GotFocus += (sender, args) =>
        {
            if (string.IsNullOrEmpty(box.Text))
            {
                box.Text = " "; // when empty, we put a space in the box to make the dropdown appear
            }
            box.Dispatcher.BeginInvoke(() => box.IsDropDownOpen = true);
        };
    box.LostFocus += (sender, args) =>
        {
            box.Text = box.Text.Trim();
        };
    box.TextChanged += (sender, args) =>
        {
            if (!string.IsNullOrWhiteSpace(box.Text) &&
                box.FilterMode != AutoCompleteFilterMode.Contains)
            {
                box.FilterMode = AutoCompleteFilterMode.Contains;
            }

            if (string.IsNullOrWhiteSpace(box.Text) &&
                box.FilterMode != AutoCompleteFilterMode.None)
            {
                box.FilterMode = AutoCompleteFilterMode.None;
            }
        };
}