Get the Selected Item when clicking a Button within Listview

I want to be able to click the button in the Listview and get the selected item corresponding value. I don't want to tap the item in the list, I want it operated by the button only. How can I do this?

This is the Xaml

<ListView.ItemTemplate>


<ViewCell.View>

<Grid.ColumnDefinitions>


</Grid.ColumnDefinitions>



</ViewCell.View>


</ListView.ItemTemplate>

Relevant Parts from View model

public ICommand OnDownloadClicked { get; private set; }
OnDownloadClicked = new Command(() => DownloadRun());
public void DownloadRun()
{
//I need selected item here
}