Knock out validation for File input control

[Mskhan]

Hi knock out groups!!

Is there a way to create validation for file input in knock out js by using  custom validations?

Let say max limit size of file input control..

How could i get size of the file to an observable in this case???

[ajaykhy...@gmail.com]

I have a custom binding like this:

  ko.bindingHandlers['fileupload'] = {

            update: function (element, valueAccessor, allBindingsAccessor) {
                var value = ko.utils.unwrapObservable(valueAccessor())
                if (element.files.length && value) {
                    var file = element.files[0];
                    alert(file.size);
                }
            }
        };

and i used it like:

  <input type="file" name="image" id="image" data-bind="fileupload:Filesize" accept="image/*" />

So in this way i could get the file size, but i dont understand how to proceed to validate this in my model???

 this.Filesize = ko.observable(); ?? It will give empty everytime!!!

[Rakesh R]

Custom binding is one option, other than that, you can do in  a following way,

<input type="file"  data-bind="event: {change: changeMethod}">

Now in that changeMethod form the event argument you can get the files.

self.changeMethod = function(data, event)

{

self.file (event.currentTarget.files[0]);

self.fileSize(event.currentTarget.files[0].size);

}

In this way you can validate on the model value also.

Regards,
Rakesh

[Ms]

Thanx Rakesh!! this way helped me!!!

[ajaykhy...@gmail.com]

By the way could you please help me with another validation in knock out???

 

Validating Two dates

[aru...@tripmakers.com]

How to validation image dimension in knock out?