Understanding the data-binding syntax

Override the ViewDidLoad method in the FirstView.cs by the following code:

public override void ViewDidLoad()
{
base.ViewDidLoad();
var set = this.CreateBindingSet<FirstView, FirstViewModel>();
set.Bind(txtUserName).To(vm => vm.UserName);
set.Bind(lblGreeting).To(vm => vm.Greeting);
set.Bind(btnShowGreeting).To(vm => vm.GetGreetingCommand);
set.Apply();
}

MvvmCross use the fluent syntax to implement data-binding for iOS. First, MvvmCross creates the relationship between the View and the ViewModel by this code:

var set = this.CreateBindingSet<FirstView, FirstViewModel>();

Then you can set the data-binding by For and To methods:

set.Bind(txtUserName).For(x => x.Text).To(vm => vm.UserName);

If For is not provided, MvvmCross will set the default view property. For example, the Text property will be used for a Label control. For more default view properties information, check this document here: https://www.mvvmcross.com/documentation/fundamentals/data-binding.

With the fluent syntax we can continue to specify the binding type, such as OneWay, and TwoWay, etc, like this:

set.Bind(txtUserName).For(x => x.Text).To(vm => vm.UserName).TwoWay();

At last, DO NOT forget to call the Apply method to apply the data-binding:

set.Apply();

We can build and launch the iOS project now. Here is the result: