knockoutjs with mvc collection model binding - asp.net-mvc-3

Question

I'm using knockoutjs to render a collection of items. After allowing the user to do some inline editing I need to post the collection back to the server. However, the collection isn't being populated on the server because I'm not using the name="[0].Blah" naming convention. Does anyone know how to either render name attributes like this using knockoutjs OR how to create a model binder that will allow me to extract the values from the ValueProvider?
You can see a screenshot of the ValueProvider during debugging below.
http://i.imgur.com/zSU5Z.png
Here is my managed ViewModel:
public class FundLevelInvestmentUploadResult
{
public string FileName { get; set; }
public IList<FundLevelInvestmentViewModel> Items { get; set; }
public int NumberOfErrors { get; set; }
public bool ShowErrorsOnly { get; set; }
public FundLevelInvestmentUploadResult()
{
Items = new List<FundLevelInvestmentViewModel>();
}
}
Here is the managed class for "Items":
public class FundLevelInvestmentViewModel
{
private string _fund;
private string _fundType;
private string _date;
private string _netOfWaivedFees;
private string _waivedFees;
private string _bcip;
private string _fxRate;
public uint RowIndex { get; set; }
public int? DealCode { get; set; }
public bool DealCodeIsValid { get; set; }
public string Fund
{
get { return _fund; }
set { _fund = GetString(value); }
}
public bool FundIsValid { get; set; }
public string FundType
{
get { return _fundType; }
set { _fundType = GetString(value); }
}
public bool FundTypeIsValid { get; set; }
public string DateOfInvestment
{
get { return _date; }
set { _date = GetString(value); }
}
public bool DateOfInvestmentIsValid { get; set; }
public string NetOfWaivedFees
{
get { return _netOfWaivedFees; }
set { _netOfWaivedFees = GetString(value); }
}
public bool NetOfWaivedFeesIsValid { get; set; }
public string WaivedFee
{
get { return _waivedFees; }
set { _waivedFees = GetString(value); }
}
public bool WaivedFeeIsValid { get; set; }
public string BCIP
{
get { return _bcip; }
set { _bcip = GetString(value); }
}
public bool BCIPIsValid { get; set; }
public string ExchangeRateToUSD
{
get { return _fxRate; }
set { _fxRate = GetString(value); }
}
public bool ExchangeRateToUSDIsValid { get; set; }
public string FileName { get; set; }
private IList<string> _errors;
public IList<string> Errors
{
get { return _errors ?? (_errors = new List<string>());}
set { _errors = value; }
}
public bool Show { get; set; }
public FundLevelInvestmentViewModel()
{
Errors = new List<string>();
Show = true;
}
// knockoutjs is returning "null" instead of "" for a null object when calling ko.mapping.fromJS
private string GetString(string value)
{
if (value == "null")
return string.Empty;
return value;
}
}
Here is my knockout viewModel:
var viewModel = {
FileData: ko.observableArray([]),
validateFile: function (file, event) {
$.ajax({
type: 'post',
url: newUrl,
data: ko.mapping.toJS(file)
}).done(function (data) {
var newFile = ko.mapping.fromJS(data);
var index = file.Items.indexOf(file);
viewModel.FileData.replace(file, newFile);
});
}
};

Answer 1

If you are using version 2.1.0.0 or later of knockout you can render the name attribute as follows from an observable array.
<input data-bind='attr: { name: "Items["+$index()+"].DealCode"}' />