How to perform an action in Prism's "OnNavigatingTo" for any and all classes

Question

Given I have about 100 classes in my Prism application project, a project can become difficult to debug for other devs. I am looking for a way to show a toast when a user navigates to any page. This toast message will tell the user the respective view model page title of the current view.

public class AViewModel 
{
   public override void OnNavigatingTo(INavigationParameters parameters)
   {
      Toast("AViewModel")
   }
}

public class BViewModel 
{
    public override void OnNavigatingTo(INavigationParameters parameters)
    {
        Toast("BViewModel")
    }
}

public class CViewModel 
{
   public override void OnNavigatingTo(INavigationParameters parameters)
   {
      Toast("CViewModel")
   }
}

public class DViewModel 
{
   public override void OnNavigatingTo(INavigationParameters parameters)
   {
      Toast("DViewModel")
   }
}

Im looking to achieve such functionality without actually including Toast("ViewModelName") in every class. Is there a way I can override something and implement this?

If this question is about a WPF or Xamarin project, please add the corresponding tag to your question. — thatguy, Jul 24 '20 at 11:56

score 0 · Answer 1 · edited Jul 27 '20 at 11:18

It is easy to achieve in few steps like below

Create a BaseViewModel class

public class BaseViewModel : INavigationAware
 {
     string PageName { get; set; }
     public BaseViewModel(string pageName)
     {
         PageName = pageName;
     }
     public virtual void OnNavigatedFrom(INavigationParameters parameters)
     {
       //Methods gets called when current active page navigated to some other page
     }

 public virtual void OnNavigatedTo(INavigationParameters parameters)
 {
   //Methods gets called when current page is activated

   //System.Diagnostics.StackFrame stackFrame = new System.Diagnostics.StackFrame(1);
   //Toast(stackFrame.GetMethod().DeclaringType.Name);

   Toast(PageName);
 }
}

Inherit BaseViewModel class for each of ur ViewModel class

public class AViewModel : BaseViewModel {
  //Constructor
  public AViewModel() : base(nameof(AViewModel))
  {
     //Some code
  }

//MethodA
public void MethodA()
{
    //Some code
} }

Note:-

base(nameof(AViewModel))

I hope this will help

Thank you for the response. It does work but was trying to eliminating having to add a parameter into every ViewModel. — tendai, Jul 30 '20 at 09:24

How to perform an action in Prism's "OnNavigatingTo" for any and all classes

1 Answers1