Get Registry key value for 32 and 64 bit machines

Here is the snippet that pulls a LOCALMACHINE\SOFTWARE

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Binding html select using knockoutjs and asp.net mvc

Suppose we have a ViewModel like this


The markup to populate HTML Select should be

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Server side paging, filtering and sorting using datatables

Nothing better than writing some code to explain a feature. This post shows how to do server-side paging in a table using datatables.net
The idea is to display a table with a large amount of data (68k rows). As it's not a good practice to load all at once, it' better to implement server-side paging.

First download datatables.net from here and reference them in your html file.

In our sample we are using a table Tasks with 3 fields, ie, TaskID, TaskName, Complete

Lets create the HTML markup first



Now lets wire up datatable to the table



Here as you can see TaskID and TaskName are sortable and searchable.
Now, the model that is passed from datatables to server-side



Finally, the controller method


That's all to it. Happy coding!

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Utility function to make an array observable in knockoutjs

Suppose we have an array

var employees = [
    { EmployeeID: 1, EmployeeName: "Naveen" },
    { EmployeeID: 2, EmployeeName: "Shebin" }
];

We can make it an observable array by calling it like this

var observableEmployees = ko.observableArray( employees );

But as per knockoutjs documentation,

Simply putting an object into an observableArray doesn’t make all of that object’s properties themselves observable. Of course, you can make those properties observable if you wish, but that’s an independent choice. An observableArray just tracks which objects it holds, and notifies listeners when objects are added or removed.

 This means that any change in array will be remembered. ie, adding and removing elements in an array is observed. But changes to properties are not remembered. That is if employee[0].EmployeeName is changed to Noah, it wont be remembered. To do that we have to make each property ko.observable. Here is a small utility function to do so.

function MakeArrayKoObservableObjectArray(arr) {
    var observableArr = [];
    for (var i = 0; i < arr.length; i++) {
        var observableObj = {}, obj = arr[i];
        for (var prop in obj) {
            if (obj.hasOwnProperty(prop)) {
                observableObj[prop] = ko.observable(obj[prop]);
            }
        }
        observableArr.push(observableObj);
    }
    return observableArr;
}

Now we can call it like this.

employees = MakeArrayKoObservableObjectArray( employees  );
var observableEmployees = ko.observableArray( employees );

Happy Coding!

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Remote validation using jQuery Validate

This is how jQuery validate is done in ASP.NET MVC

Markup

<form id="manager-form" action="">
    <p>
        <label style="display:inline-block; width: 200px;">Manager Name</label>
        <input type="text" id="Manager" name="Manager" />
    </p>
    <p>
        <input type="submit" id="saveManager" class="btn btn-primary" value="Save Sales Person" />
    </p>
</form>

JavaScript

    function SetValidationRules(){
        $("#manager-form").validate({
            onkeyup: false,
            rules: {
                Manager: {
                    required: true,
                    minlength: 3,
                    remote: {
                        url: '/Manager/IsManagerNameTaken',
                        type: 'POST',
                        dataType: 'json',
                        data: {
                            managerName: function () {
                                return $('#Manager').val();
                            }
                        }
                    }
                }
            },
            messages: {
                Manager: {
                    required: "Manager name is required.",
                    minlength: "Manager name should be 3 atleast characters."
                }
            }
        });
    }

Controller

    public ActionResult IsManagerNameTaken(string managerName)
    {
        var result = ManagerRepository.IsManagerNameTaken(managerName) ?
            "Manager name is already taken. Try another!" : "";
        return Json(result);
    }

Thats all to it. Happy coding!

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Overriding jQuery ajaxStart and ajaxStop locally

While performing ajax calls, I use to provide provide visual indicators for better user experience.
My preferred method is showing a modal at jQuery.ajaxStart which gets hidden at jQuery.ajaxStop

The code goes like this

    $(document).on("ajaxStart", function () {
        $("#jQueryAjaxmodal").modal("show");
    }).on("ajaxStop", function () {
        $("#jQueryAjaxmodal").modal("hide");
    });

But this causes problem when one uses something like jQuery.autocomplete as ajaxStart fires on every keyup. To override this for a particular page, do this

1. Namespace the ajaxStart and ajaxStop like this

    $(document).on("ajaxStart.myblock", function () {
        $("#jQueryAjaxmodal").modal("show");
    }).on("ajaxStop.myblock", function () {
        $("#jQueryAjaxmodal").modal("hide");
    });

2. Now on the DOM Ready of the page on which you wanna override this behaviour, unbind it

    $(document).on("ready", function () {
        $(document).off(".myblock");
    });

Courtesy: jQuery should I use multiple ajaxStart/ajaxStop handling

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Validating date in JavaScript

People make me want to cry when they validate date using regular expression.

Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems.

IMHO, its much simpler to use Date.Parse. For example,

var myDateString = '01-Aug-12​';
var isValidDate = !isNaN( Date.parse( myDateString ));

Happy Coding!

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