Using GotFocus and TextChanged simultaneously - Wi

问题:

I have an AutoSuggestBox which is set to handle the events GotFocus & TextChanged simultaneously. I have cleared the text from the text box in GotFocus event. Now the problem is that when I select any of the suggestions in AutoSuggestBox, after selecting it calls the GotFocus event handler and clears the selected text from it.

This is the MainPage.xaml code using the AutoSuggestBox:

        <AutoSuggestBox
            x:Name="auto_text_from"
            HorizontalAlignment="Left"
            VerticalAlignment="Center"
            PlaceholderText="Enter Source"
            Height="auto"
            Width="280"
            GotFocus="auto_text_from_GotFocus"
            TextChanged="AutoSuggestBox_TextChanged"/>

And this one is the code which I have written in MainPage.xaml.cs :

    private void auto_text_from_GotFocus(object sender, RoutedEventArgs e)
    {
        auto_text_from.Text = "";
    }


    string[] PreviouslyDefinedStringArray = new string[] {"Alwar","Ajmer","Bharatpur","Bhilwara",
        "Banswada","Jaipur","Jodhpur","Kota","Udaipur"};


    private void AutoSuggestBox_TextChanged(AutoSuggestBox sender,AutoSuggestBoxTextChangedEventArgs args)
    {
        List<string> myList = new List<string>();
        foreach (string myString in PreviouslyDefinedStringArray)
        {
            if (myString.ToLower().Contains(sender.Text.ToLower()) == true)
            {
                myList.Add(myString);
            }
        }
        sender.ItemsSource = myList;
    }

I want to use both of the event handlers. GotFocus for clearing the data of Text box, and TextChanged for showing the suggestions of writing the text in it.

Please suggest me any way to do the same.

Thanks in Advance :)

回答1:

If AutoSuggestBox has an event to handle the selection of a suggested word, like "SuggestionChosen", a possibile solution is using a private flag managed between the various handlers.

Set a private field:

private bool _isSelectingSuggestion;

Link a method-handler like OnSuggestionChosen to the event SuggestionChosen and implement it like that:

private void OnSuggestionChosen(object sender, RoutedEventArgs e)
{
    _isSelectingSuggestion = true;
}

Then, in GotFocus, check the flag like this:

private void auto_text_from_GotFocus(object sender, RoutedEventArgs e)
{
    if (_isSelectingSuggestion)
        e.Handled = true;
    else
        auto_text_from.Text = "";

   _isSelectingSuggestion = false;
}

Obviously this works only if SuggestionChosen is raised before GotFocus: when GotFocus begins, it proceeds like: "ok, I've got focus because a suggestion was chosen just a moment ago? If it's true, I must not clear my Text! Otherwise, I shall clear it!".

Let me know it this work for you!

回答2:

@MK87 : Yeah it worked with little bit of changes !! :)

    private bool _isSelectingSuggestion;

    private void OnSuggestionChosen(AutoSuggestBox sender, AutoSuggestBoxSuggestionChosenEventArgs args)
    {
        _isSelectingSuggestion = true;
    }

    private void auto_text_from_GotFocus(object sender, RoutedEventArgs e)
    {
        if (!_isSelectingSuggestion)
            auto_text_from.Text = "";

        _isSelectingSuggestion = false;
    }

I had to remove this line:

e.Handled == true;

as it was giving me error as RoutedEventArgs does not contain a definition for 'Handled'.

Thanks for your help :) :)