Trigger Xamarin.Forms Picker

18
votes

Can i Trigger a Picker programatically?

I would like a button beside the picker that indicates that the picker is a clickable "dropdown". But how could I open the picker when the button is clicked?

3
xamarin.forms
BTW, if Picker class isn't providing what you want, a more flexible approach is seen in "Action Sheet" sample in Allan Ritchie - "ACR.UserDialogs" nuget src. Defined via a descriptive config object in StandardViewModel.CreateActionSheetCommand. On UWP, this is based on UWP XAML ContentDialog class. On iOS and Android, appropriate native controls are built. – ToolmakerSteve
... I'm not sure why that nuget doesn't instead build on Xamarin Forms ContentView class - doing so would make it easier to generate custom cross-platform dialogs. I mention the UWP implementation above, because it looks like something that could be adapted to use X-Forms views w/i a contentview. See UserDialogsImpl under Platforms / UWP. – ToolmakerSteve

3 Answers

14
votes

You can name the picker (e.g. myPicker) and call its Focus event. Do make sure that you're on the main thread at the time you're calling myPicker.Focus()

9
votes

As @Hutjepower and this xamarin forums post mentions, the following code should work:

Device.BeginInvokeOnMainThread(() =>
{
    if (yourPicker.IsFocused)
        yourPicker.Unfocus();

    yourPicker.Focus();
});

However I have found that it does not currently work on Windows 8.1 and UWP apps, at least in the latest 2.3.4-pre1 version of Xamarin.Forms. I haven't tested it on any phone/tablet devices yet though. Hopefully this bug will get fixed up in a later release. I have created a bug report for this problem.

1
votes

Unfortunately not; the inner workings of the picker are almost entirely in the renderers and are not exposed via an API.