Null Value is passing to Controller

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jsshivalik

Member

113 Points

415 Posts

Null Value is passing to Controller

Oct 23, 2019 07:04 AM|jsshivalik|LINK

Hi

I have below code and Parameter is of string datatype

public JsonResult DeleteUser(string UsrName)
        {
            return Json(usrDB.DeleteUser(UsrName), JsonRequestBehavior.AllowGet);
        }

function Delete(UsrName) {
    var ans = confirm("Are you sure you want to delete this Record?");
    if (ans) {
        $.ajax({
            url: '/Home/DeleteUser/',
            data: JSON.stringify({ UserName : UsrName }),
            type: "POST",
            contentType: "application/json;charset=UTF-8",
            dataType: "json",
            success: function (result) {
                loadData();
            },
            error: function (errormessage) {
                alert(errormessage.responseText);
            }
        });
    }
}

Thanks

Reply

Yongqing Yu

Contributor

3100 Points

898 Posts

Re: Null Value is passing to Controller

Oct 23, 2019 09:23 AM|Yongqing Yu|LINK

Hi jsshivalik,

According to your code, I found that the parameter you passed from Ajax is just a string type UsrName, not an entity .

I made a case of deleting data in MVC. You can refer to the following code:

@{
    Layout = null;
}

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
    <script src="~/Scripts/jquery-3.3.1.min.js"></script>
    <script type="text/javascript">
 
        function Delete(UsrName) {
            event.preventDefault();
            var ans = confirm("Are you sure you want to delete this Record?");
            if (ans) {
                $.ajax({
                    url: '/C_1023_2160919/DeleteUser',
                    data: "{ UsrName:'" + $(UsrName).attr('id') + "'}",
                    type: "POST",
                    contentType: "application/json;charset=UTF-8",
                    dataType: "json",
                    success: function (result) {
                        alert(result);
                        location.href = "/C_1023_2160919/Index";
                    },
                    error: function (errormessage) {
                        alert(errormessage.responseText);
                    }
                });
            }
        }


    </script>
</head>
<body>
    <table id="tblCustomers" class="table" cellpadding="0" cellspacing="0" style="border-collapse:collapse;text-align:center" border="1">
        <tr>
            <th style="width:100px">EmplId</th>
            <th style="width:150px">FirstName</th>
            <th style="width:100px">LastName</th>
            <th style="width:150px">EmailAddr</th>
        </tr>
        @foreach (var customer in Model)
        {
            <tr>
                <td class="EmplId">
                    <span>@customer.EmplId</span>
                </td>
                <td class="FirstName">

                    <span>@customer.FirstName</span>
                </td>
                <td class="FirstName">

                    <span>@customer.LastName</span>
                </td>
                <td class="FirstName">

                    <span>@customer.EmailAddr</span>
                </td>
                <td>
                    @Html.ActionLink("Delete", "Delete", null, new { id = customer.EmplId, @class = "delete", onclick = "Delete(this);" })
                </td>
            </tr>
        }
    </table>

</body>
</html>

 public class C_1023_2160919Controller : Controller
    {
        // GET: C_1023_2160919
        public ActionResult Index()
        {
            Entities2 entity = new Entities2();
            List<Employee> customers = entity.Employees.ToList();
            return View(customers);
        }
        [HttpPost]
        public JsonResult DeleteUser(string UsrName)
        {
            return Json(DeleteUserMethod(UsrName), JsonRequestBehavior.AllowGet);
        }
        public string DeleteUserMethod(string UsrName)
        {
            string deleteMessage = string.Empty;
            int id = Convert.ToInt32(UsrName);
            try
            {
                using (EntityData entities = new EntityData())
                {
                    Employee customer = (from c in entities.Employees
                                         where c.EmplId == id
                                         select c).FirstOrDefault();
                    entities.Employees.Remove(customer);
                    entities.SaveChanges();
                }
                deleteMessage = "delete successfully!";
            }
            catch (Exception ex)
            {
                deleteMessage = ex.Message.ToString();
            }

            return deleteMessage;


        }
    }

Here is the result of this work demo:

Best Regards,

YongQing.

MSDN Community Support

Please remember to click "Mark as Answer" the responses that resolved your issue.

If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com.

Reply

jsshivalik

Member

113 Points

415 Posts

Re: Null Value is passing to Controller

Oct 23, 2019 01:49 PM|jsshivalik|LINK

Hi Yong

I have below html

function loadData() {
    $.ajax({
        url: "/Home/List",
        type: "GET",
        contentType: "application/json;charset=utf-8",
        dataType: "json",
        success: function (result) {
            var html = '';
            $.each(result, function (key, item) {
                html += '<tr>';
                html += '<td>' + item.UserName + '</td>';
                html += '<td>' + item.Password + '</td>';
                html += '<td>' + item.FirstName + '</td>';
                html += '<td>' + item.LastName + '</td>';
                html += '<td><a href="#" onclick="return getbyName(\'' + item.UserName + '\')">Edit</a> | <a href="javascript:void(0)" onclick="Delete(\'' + item.UserName + '\')">Delete</a></td>';
                html += '</tr>';
            });
            $('.tbody').html(html);
        },
        error: function (errormessage) {
            alert(errormessage.responseText);
        }
    });
}

Thanks

Reply

DA924

Contributor

4081 Points

3444 Posts

Re: Null Value is passing to Controller

Oct 23, 2019 06:01 PM|DA924|LINK

/Home/GetbyName?UsrName=" + '$('#UserName').val(result.UserName).ToString();

You can't do something like above? It's been sometime since I have used Jquery
And Username is spelled wrong in the action method too.

If you find the post has answered your issue, then please mark post as 'answered'.

Reply

Yongqing Yu

Contributor

3100 Points

898 Posts

Re: Null Value is passing to Controller

Oct 24, 2019 05:44 AM|Yongqing Yu|LINK

Hi jsshivalik,

According to your code, you didn't explain the issue you were having, but I combined the data loading code and the deletion method you provided to create a case that you can refer to:

@{
    Layout = null;
}

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
    <script src="~/Scripts/jquery-3.3.1.min.js"></script>
    <script type="text/javascript">
        function loadData() {
            $.ajax({
                url: "/C_1023_2160919/List",
                type: "GET",
                contentType: "application/json;charset=utf-8",
                dataType: "json",
                success: function (result) {
                    var html = '';
                    $.each(result, function (key, item) {
                        html += '<tr>';
                        html += '<td>' + item.EmplId + '</td>';
                        html += '<td>' + item.FirstName + '</td>';
                        html += '<td>' + item.LastName + '</td>';
                        html += '<td>' + item.EmailAddr + '</td>';
                        html += '<td><a href="#" onclick="return getbyName(\'' + item.EmplId + '\')">Edit</a> | <a href="javascript:void(0)" onclick="Delete(\'' + item.EmplId + '\')">Delete</a></td>';
                        html += '</tr>';
                    });
                    $('.tbody').html(html);
                },
                error: function (errormessage) {
                    alert(errormessage.responseText);
                }
            });
        }
        function Delete(UsrName) {
            event.preventDefault();
            var ans = confirm("Are you sure you want to delete this Record?");
            if (ans) {
                $.ajax({
                    url: '/C_1023_2160919/DeleteUser',
                    data: "{ UsrName:'" + UsrName + "'}",
                    type: "POST",
                    contentType: "application/json;charset=UTF-8",
                    dataType: "json",
                    success: function (result) {
                        alert(result);
                        loadData();
                    },
                    error: function (errormessage) {
                        alert(errormessage.responseText);
                    }
                });
            }
        }


    </script>
</head>
<body onload="loadData()">
    <table id="tblCustomers" class="table" cellpadding="0" cellspacing="0" style="border-collapse:collapse;text-align:center" border="1">
        <thead>
            <tr>
                <th style="width:100px">EmplId</th>
                <th style="width:150px">FirstName</th>
                <th style="width:100px">LastName</th>
                <th style="width:150px">EmailAddr</th>
                <th> </th>
            </tr>
        </thead>
        <tbody class="tbody"></tbody>
    </table>

</body>
</html>

public class C_1023_2160919Controller : Controller
    {
        // GET: C_1023_2160919
        public ActionResult Index()
        {
            return View();
        }
        [HttpGet]
        public JsonResult List()
        {
            Entities2 entity = new Entities2();
            List<Employee> customers = entity.Employees.ToList();
            return Json(customers, JsonRequestBehavior.AllowGet);
        }
        [HttpPost]
        public JsonResult DeleteUser(string UsrName)
        {
            return Json(DeleteUserMethod(UsrName), JsonRequestBehavior.AllowGet);
        }
        public string DeleteUserMethod(string UsrName)
        {
            string deleteMessage = string.Empty;
            int id = Convert.ToInt32(UsrName);
            try
            {
                using (EntityData entities = new EntityData())
                {
                    Employee customer = (from c in entities.Employees
                                         where c.EmplId == id
                                         select c).FirstOrDefault();
                    entities.Employees.Remove(customer);
                    entities.SaveChanges();
                }
                deleteMessage = "delete successfully!";
            }
            catch (Exception ex)
            {
                deleteMessage = ex.Message.ToString();
            }

            return deleteMessage;


        }
    }

Here is the result of this work demo:

Best Regards,

YongQing.

MSDN Community Support

Please remember to click "Mark as Answer" the responses that resolved your issue.

If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com.

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