use lambda expressions as parameter in Dispatcher.Invoke()

Question

I have such problem : there is some method

private List<int> GetStatusList()
        {
            return (List<int>)GetValue(getSpecifiedDebtStatusesProperty);
        }

To invoke it in main thread - I use

`delegate List<int> ReturnStatusHandler();` ...

this.Dispatcher.Invoke(new ReturnStatusHandler(GetStatusList));

How can I do the same, using lambda expression instead of custom delegate and method?

http://stackoverflow.com/questions/4936459/dispatcher-begininvoke-cannot-convert-lambda-to-system-delegate — Amittai Shapira, Oct 10 '11 at 08:57

score 15 · Answer 1 · answered Oct 10 '11 at 10:37

15

you can pass this:

new Action(GetStatusList)

or

(Action)(() => { GetStatusList; })

answered Oct 10 '11 at 10:37

Mohamed Abed

gls123 · Answer 2 · 2013-04-22T13:59:39.137

7

You can avoid explicit casting by creating a simple method:

void RunInUiThread(Action action)
{
     Dispatcher.Invoke(action);
}

Use this as follows:

RunInUiThread(() =>
{
     GetStatusList();
});

edited Apr 22 '13 at 13:59

answered Dec 13 '12 at 13:55

gls123

Hi, i have 2 problems with your sample code. first, last line has a missing ')'. Second if i try your example i get an error, that for the non static field Dispatcher.Invoke(System.Action) a object reference is needed. – Offler Apr 22 '13 at 06:47
Thanks I have applied correction to the above. Dispatcher is a non-static property on a DispatcherObject, which is the lowest base class of Control, Window, FrameworkElement etc. So you can only use Dispatcher in non-static contexts. – gls123 Apr 22 '13 at 14:02

2 Answers2