Setting a combined optionsText in knockout.js

Question

I want to combine two return values in my optionsText field, I thought this would be simple, but I am apparently wrong. I'm also using a value for the options field that is outside the normal view model. Here is the original: ``` ``` Uncaught TypeError: Property 'FirstName' of object # is not a function

Accepted Answer

You sure FirstName and LastName are observables? If you're not sure, try this:

```
optionsText: function(item) { return ko.unwrap(item.FirstName) + '-' + ko.unwrap(item.LastName); }
```

Or better yet, create a computed in your viewmodel:

```
self.FullName = function() {
    return ko.unwrap(self.FirstName) + '-' + ko.unwrap(self.LastName);
};
```

And:

```
optionsText: 'FullName'
```

Setting a combined optionsText in knockout.js

Solution

Problem