Need advice on binding to use Commands

Question

Need advice on binding to use Commands

Lloyd Sheen 1,481

I have a ContentPage which has two ContentViews, the whole thing has one ViewModel.

In one of the views there is a CollectionView and in the DataTemplate for the items it has a Lable with a TapGestureRecognizer. Now that TapGestureRecognizer has an ICommand which handles the tap and this is where I have a problem.

I had to define the Command in the Class that is the Item. That works but is where the problem is. The tap event needs to set an ItemsSource and I have had to define the CollectionView as the parameter to the Command event in order for it to know where to set the ItemsSource.

What is the way (or is there a good way) to be able to do this without all the references to controls. The same problem would occur if I use the ViewModel property to bind the ItemsSource.

Wenyan Zhang (Shanghai Wicresoft Co,.Ltd.) 36,161 Reputation points Microsoft External Staff

2023-12-25T07:25:04.5+00:00

I had to define the Command in the Class that is the Item. That works but is where the problem is. The tap event needs to set an ItemsSource and I have had to define the CollectionView as the parameter to the Command event in order for it to know where to set the ItemsSource.

You mean your main purpose is to get the ItemScorce of the CollectionView, right? If you set the ViewModel for your page and set BindingContext for the CollectionView, the ItemSource(may be an ObservableCollection<T>) should be found in the ViewModel class and you could try to find the ObservableCollection<T> object.

The same problem would occur if I use the ViewModel property to bind the ItemsSource.

I'm not sure how you set the BindingContext/ViewModel and what the CollectionView looks like. Could you provide more code snippets about your XAML and ViewModel? It will be easier to investigate the issue and provide further help.

Also, on which platform did you encounter this problem? What's the detailed MAUI version?

Your answer

Wenyan Zhang (Shanghai Wicresoft Co,.Ltd.) 36,161 Reputation points Microsoft External Staff

2023-12-25T07:25:04.5+00:00

I had to define the Command in the Class that is the Item. That works but is where the problem is. The tap event needs to set an ItemsSource and I have had to define the CollectionView as the parameter to the Command event in order for it to know where to set the ItemsSource.

You mean your main purpose is to get the ItemScorce of the CollectionView, right? If you set the ViewModel for your page and set BindingContext for the CollectionView, the ItemSource(may be an ObservableCollection<T>) should be found in the ViewModel class and you could try to find the ObservableCollection<T> object.

The same problem would occur if I use the ViewModel property to bind the ItemsSource.

I'm not sure how you set the BindingContext/ViewModel and what the CollectionView looks like. Could you provide more code snippets about your XAML and ViewModel? It will be easier to investigate the issue and provide further help.

Also, on which platform did you encounter this problem? What's the detailed MAUI version?

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Need advice on binding to use Commands

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