MonoTouch MVVMCross binding to instance variables

Question

This probably sounds really stupid, but I just can\'t get a binding to an instance variable (of type string) to work.

In my view\'s xib, I create a text field as an outl

Answer 1

From reading your question, I think what you are saying is that the View itself has a field of type string...

Your code:

this.AddBindings(
     new Dictionary<object, string>()
     {
          { StringTemp, "{'Text':{'Path':'AboutText'}}" },
     });

is trying to bind the property Text on the object referred to by StringTemp to whatever is in AboutText on the ViewModel.

---

To set the StringTemp string itself you should be able to bind to it using something like:

 this.AddBindings(
      new Dictionary<object, string>()
      {
           { this, "{'StringTemp':{'Path':'AboutText'}}" },
      });

---

Just to explain the parts in: { this, "{'StringTemp':{'Path':'AboutText'}}" }, these can be thought of as { TargetObject, "{'TargetPropertyName':{'Path':'SourcePropertyName'}}" } where:

• TargetObject (this) is the object you are aiming to set property values on
• TargetPropertyName (StringTemp) is the name property that you are aiming to set
• SourcePropertyName (AboutText) is the name of the property that will be the source of the value

Note that Mvx uses Properties - not fields - so private string StringTemp {get;set;} is bindable, but private string StringTemp; is not.

---

You could also do two-way binding for this string reference if you wanted to... but you would need to setup some custom binding information to do so - there would need to be some event fired and captured in order to update the ViewModel (I'll leave that for another day!)

---

For situations where direct binding isn't what you are looking for, then you can always subscribe to PropertyChanged and handle the notifications in more verbose code... e.g.:

ViewModel.PropertyChanged += (s,e) => 
{
    if (e.PropertyName == "AboutText")
    {
         // do something complicated here with the new ViewModel.AboutText value
    }
};

...but I personally tend to avoid this type of code where I can...