MoveToTop Extension

MoveToTop.cs

// Create our model
class Model {
    public int Id {get;set;}
    public string Name {get;set;}
}

// Create handy extension (from: https://stackoverflow.com/a/2576736/461998)
static void MoveToTop<T>(this List<T> list, int index)
{
    T item = list[index];
    for (int i = index; i > 0; i--)
        list[i] = list[i - 1];
    list[0] = item;
}

// Initialize model
var models = new List<Model>();
models.Add(new Model() { Id=1, Name="First"});
models.Add(new Model() { Id=2, Name="Second"});
models.Add(new Model() { Id=3, Name="Third"});

// Find index for bottom item
var idx = models.FindIndex(i => i.Id==3);

// Move bottom item to top
if (idx != -1)
    models.MoveToTop(idx);

// Display results
foreach (var i in models)
    Console.WriteLine($"Id: {i.Id} Name: {i.Name}");