Difference between SingleOrDefault() n FirstOrDefault()

Whenever you use SingleOrDefault, you clearly state that the query should result in at most a single result. On the other hand, when FirstOrDefault is used, the query can return any amount of results but you state that you only want the first one.

I personally find the semantics very different and using the appropriate one, depending on the expected results, improves readability.

AngularJS ASP.NET MVC Editable Grid

Model-------------

public class Employee

    {

        public string FirstName { get; set; }

        public string LastName { get; set; }

        public string Country { get; set;

   }

View......

<link href="../../style/bootstrap.min.css" rel="stylesheet" type="text/css" />

<script src="../../script/angular.js" type="text/javascript"></script>

<script type="text/javascript">

    var app = angular.module('myApp', []);

    app.controller('HomeCtrl', ['$scope', '$http', function ($scope, $http) {

        $http({

            method: 'POST',

            url: 'Home/GetEmployees'

        })

        .then(function (response) {

            console.log(response);

            $scope.employees = response.data.employees;

            angular.forEach($scope.employees, function (obj) {

                obj["showEdit"] = true;

            });

        }, function (error) {

            console.log(error);

        });

        $scope.toggleEdit = function (emp) {

            emp.showEdit = emp.showEdit ? false : true;

        }

    } ]);

</script>

<div ng-app="myApp" ng-controller="HomeCtrl" class="container">

    <div class="row">

        <div class="bs-example marginTop50" data-example-id="table-within-panel">

            <div class="panel panel-default">

                <div class="panel-heading">

                    <h3>Code Handbook</h3></div>

                <div class="panel-body">

                    <p>

                        AngularJS ASP.NET MVC Editable Grid Demo</p>

                </div>

                <table class="table">

                    <thead>

                        <tr>

                            <th>

                                #

                            </th>

                            <th>

                                First Name

                            </th>

                            <th>

                                Last Name

                            </th>

                            <th>

                                Country

                            </th>

                            <th>

                            </th>

                        </tr>

                    </thead>

                    <tbody>

                        <tr ng-repeat="emp in employees">

                            <th scope="row">

                                {{$index+1}}

                            </th>

                            <td>

                                <span ng-show="emp.showEdit">{{emp.FirstName}}</span>

                                <input ng-show="!emp.showEdit" type="text" ng-model="emp.FirstName" class="form-control" >

                            </td>

                            <td>

                                 <span ng-show="emp.showEdit">{{emp.LastName}}</span>

                                 <input ng-show="!emp.showEdit" type="text" ng-model="emp.LastName" class="form-control" >

                            </td>

                            <td> <span ng-show="emp.showEdit">{{emp.Country}}</span>

                                <input ng-show="!emp.showEdit" type="text" ng-model="emp.Country" class="form-control" >

                            </td>

                            <td>

                                <span ng-show="emp.showEdit" ng-click="toggleEdit(emp)" class="glyphicon glyphicon-pencil"></span>

                                <span ng-show="!emp.showEdit" ng-click="toggleEdit(emp)" class="glyphicon glyphicon-ok"></span>

                            </td>

                        </tr>

                    </tbody>

                </table>

            </div>

        </div>

    </div>

</div>

Controller----

public JsonResult GetEmployees()

        {

            List<Employee> empList = new List<Employee>();

            Employee emp = new Employee { FirstName = "James", LastName = "Bond", Country = "Germany" };

            empList.Add(emp);

            emp = new Employee { FirstName = "Roy", LastName = "Agasthyan", Country = "United States" };

            empList.Add(emp);

            return Json(new { employees = empList });

        }

Disable browser right click and F12 keyboard codes javascript

<body oncontextmenu="return disableRightClick();">

<script type="text/javascript">

    function disableRightClick() {

        //alert("Sorry, right click is not allowed !!");

        return false;

    }

    document.onkeypress = function(event) {

        event = (event || window.event);

        if (event.keyCode == 123) {

            return false;

        }

    };

    document.onmousedown = function(event) {

        event = (event || window.event);

        if (event.keyCode == 123) {

            return false;

        }

    };

    document.onkeydown = function (event) {

        event = (event || window.event);

        if (event.keyCode == 123) {

            return false;

        }

        if ((event.ctrlKey && (event.keyCode === 85 || event.keyCode === 117)) || (event.ctrlKey && event.shiftKey && event.keyCode === 73) || (event.ctrlKey && event.shiftKey && event.keyCode === 67)) {

            //alert('not allowed');

            return false;

        } else {

            return true;

        }

    }

</script>

Key Code
backspace 8
tab 9
enter 13
shift 16
ctrl 17
alt 18
pause/break 19
caps lock 20
escape 27
(space) 32
page up 33
page down 34
end 35
home 36
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right arrow 39
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delete 46
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a 65
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d 68
Key Code
e 69
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p 80
q 81
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s 83
t 84
u 85
v 86
w 87
x 88
y 89
z 90
left window key 91
right window key 92
select key 93
numpad 0 96
numpad 1 97
numpad 2 98
numpad 3 99
numpad 4 100
numpad 5 101
numpad 6 102
numpad 7 103
Key Code
numpad 8 104
numpad 9 105
multiply 106
add 107
subtract 109
decimal point 110
divide 111
f1 112
f2 113
f3 114
f4 115
f5 116
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f9 120
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f12 123
num lock 144
scroll lock 145
semi-colon 186
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comma 188
dash 189
period 190
forward slash 191
grave accent 192
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back slash 220
close braket 221
single quote 222