如何在Xamarin表单的视图中添加和检索列表？

Question

I'm making a Xamarin app for android using .net standard 2.0 and I have quite large objects to handle. I want to make a few views for them where they are added to a list and then the user can choose from them, then I retrieve the selected object and open a more detailed view.

What approach is the best for this? So far I have them in a listview with a couple properties stitched together in a string and then I split the selected string and search for the matching object but this seems really prone to breakage as I don't know what value the objects will have until runtime.

I'd like to add them to a grid as this seems the best to customise layout wise, is it possible to add these values to a grid and attach a TapGestureRecognizer to the row, and somehow store and receive the selected object of that row?

Answer 1

If you use ICommand you can simply implement TapGestureRecognizer. First create the GridView in XAML file like this:

<Grid>
  <Grid.ColumnDefinitions>
      <ColumnDefinition Width="*"/>
      <ColumnDefinition Width="*"/>
  </Grid.ColumnDefinitions>
  <Label Text = "{Binding @something}" GridRow = 0 GridColumn = 0/>
  <Grid.GestureRecognizers>
      <TapGestureRecognizer Command="{Binding TapCommand}"/>
  </Grid.GestureRecognizers>
</Grid>

after that in c# code setting the binding like this:

var tapGestureRecognizer = new TapGestureRecognizer();
tapGestureRecognizer.SetBinding (TapGestureRecognizer.CommandProperty, "TapCommand");
grid.GestureRecognizers.Add(tapGestureRecognizer);

Then you should implement the command:

public class TapViewModel : INotifyPropertyChanged
{
  ICommand tapCommand;

  public TapViewModel () 
  {
    tapCommand = new Command (OnTapped);
  }

  public ICommand TapCommand 
  {
    get { return tapCommand; }
  }

  void OnTapped (object s)
  {
    //DO whatever you want
  }

}