Can you provide an example of using ShowViewModel with parameters

Step 1: Define a Parameter Model

First, you need to define a model that will hold the parameters you want to pass. This model should be simple and contain only public properties with both `get` and `set` access. The types of these properties can be `bool`, integral types, floating-point types, `char`, `string`, `DateTime`, or `Guid`.

csharp
public class DetailParameters
{
    public int Index { get; set; }
    public string Name { get; set; }
}

Step 2: Create the Destination ViewModel

Your destination view model should inherit from `MvxViewModel` where `TParameter` is the type of the parameter model you defined.

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csharp
public class DetailViewModel : MvxViewModel
{
    private readonly IMyService _myService;

    public DetailViewModel(IMyService myService)
    {
        _myService = myService;
    }

    public override void Prepare(DetailParameters parameter)
    {
        // Save the parameters here. Do not perform any logic here.
        Index = parameter.Index;
        Name = parameter.Name;
    }

    private int Index { get; set; }
    private string Name { get; set; }

    // Other properties and methods...
}

Step 3: Navigate Using ShowViewModel

To navigate to the `DetailViewModel` with parameters, use the `ShowViewModel` method provided by MvvmCross's navigation service. You can pass an instance of your parameter model.

csharp
public class MasterViewModel : MvxViewModel
{
    private readonly IMvxNavigationService _navigationService;

    public MasterViewModel(IMvxNavigationService navigationService)
    {
        _navigationService = navigationService;
    }

    public async Task NavigateToDetailAsync()
    {
        var parameters = new DetailParameters { Index = 2, Name = "John Doe" };
        await _navigationService.Navigate(parameters);
    }
}

Alternative: Using Anonymous Parameters

For simpler cases, you can use anonymous objects instead of defining a specific parameter class.

csharp
public class MasterViewModel : MvxViewModel
{
    private readonly IMvxNavigationService _navigationService;

    public MasterViewModel(IMvxNavigationService navigationService)
    {
        _navigationService = navigationService;
    }

    public async Task NavigateToDetailAsync()
    {
        await _navigationService.Navigate(new { index = 2, name = "John Doe" });
    }
}

In this case, your `DetailViewModel` should use the `Prepare` method without a specific type, or define an `Init` method to receive the parameters.

csharp
public class DetailViewModel : MvxViewModel
{
    public void Init(int index, string name)
    {
        // Use the parameters here
    }
}

However, using anonymous objects is limited by serialization requirements and is generally less flexible than using a defined parameter class.

Conclusion

Using `ShowViewModel` with parameters is a powerful way to pass data between view models in MvvmCross applications. By defining a parameter model and using the `Prepare` method, you can efficiently navigate and initialize view models with the required data.