Problem with Toolbar with many Items

Hello!

I have a Xamarin.Forms Project that needs a Toolbar with many items, and I'm having some problems to accomplish this.

When I have just one Item, my code Works, but when I have more than one Item, I'm getting a Exception on Android.

These code works:

this.ToolbarItems.Clear();
this.ToolbarItems.Add(new ToolbarItem("Award", "award_star_silver_3.png", () => { }));
//this.ToolbarItems.Add(new ToolbarItem("Bell", "bell.png", () => { }));
//this.ToolbarItems.Add(new ToolbarItem("Book", "book.png", () => { }));

But these code doesn't work:

this.ToolbarItems.Clear();
this.ToolbarItems.Add(new ToolbarItem("Award", "award_star_silver_3.png", () => { }));
this.ToolbarItems.Add(new ToolbarItem("Bell", "bell.png", () => { }));
this.ToolbarItems.Add(new ToolbarItem("Book", "book.png", () => { }));

What are I'm doing wrong?