Check for duplicate values when Adding a New Record in the Controller Method

I have a form with multiple Text fields.  I need to check when the user completes the form if all of the fields match an entry already in the database.  If so, return a message and send them back to another View - perhaps the one matching their entry.  

Here is my form:  I have several more fields but just included a few as an example

    @using (Html.BeginForm("Add", "MyController", FormMethod.Post, new
    {
        name = "NewForm"
    }))
    {

        <div class="panel panel-info" style="position: relative;">
            <div class="panel-heading">Add Information</div>
            <div class="panel-body">
                <div class="col-xs-12">

                    <div class="row" style="margin-top: 0; margin-bottom: 5px;">
                        <div class="col-xs-6">
                            <div style="color:red;padding-bottom:0px; display:inline">*</div>
                            @Html.Label("Select Field 1")

                        </div>
                    </div>
                    <div class="row" style="margin-top: 0; margin-bottom: 10px;">

                        <div class="col-xs-6">

                            @Html.DropDownListFor(x => x.field1, sl.getField1List(), new
                       {
                           @type = "drop",
                           @id = "field1",
                       })
                            <div class="error">
                                @Html.ValidationMessageFor(x => x.field1)
                            </div>
                        </div>
                    </div>

                    <div class="row" style="margin-top: 0; margin-bottom: 5px;">
                        <div class="col-xs-6">
                            <div style="color:red;padding-bottom:0px; display:inline">*</div>
                            @Html.Label("Select Field 2")
                        </div>
                    </div>

                    <div class="row" style="margin-top: 0;  margin-bottom: 10px;">

                        <div class="col-xs-6">

                            @Html.DropDownListFor(x => x.Field2, sl.getField2List(), new
                       {
                           @type = "drop",
                           @id = "field2",
                       })
                            <div class="error">
                                @Html.ValidationMessageFor(x => x.field2)
                            </div>
                        </div>
                   </div>

                    <div class="row" style="margin-top: 0;">
                        <div class="col-xs-4">
                            <div style="color:red;padding-bottom:0px; display:inline">*</div>
                            @Html.Label("Enter Field3")
                            @Html.TextBoxFor(x => x.field3, new {
                           @class = "form-control",
                           @maxlength = "255",
                           @placeholder = "Enter Field 3",
                           @required = "required"
                       })
                            <div class="error">
                                @Html.ValidationMessageFor(x => x.field3)
                            </div>

                        </div>

                        <div class="col-xs-4">
                            <div style="color:red;padding-bottom:0px; display:inline">*</div>
                            @Html.Label("Enter Field 4")
                            @Html.TextBoxFor(x => x.field4, new {
                                @class = "form-control",
                                @maxlength = "255",
                                @placeholder = "Enter Field 4",
                                @required = "required"
                            })
                            <div class="error">
                                @Html.ValidationMessageFor(x => x.field4)
                            </div>
                        </div>

                </div>

                    <div class="row">
                        <div class="col-xs-12">
                            @Html.ActionLink("Cancel", "Index", "myController", null, new {
                                @class = "btn btn-danger",
                                @style = "float: left; margin-left: 20px"
                            })

                            <button type="submit" class="btn btn-success" style="float: right;" onclick="add.formSubmit(this.form);">
                                Add
                            </button>
                        </div>
                    </div>

                </div>
        </div>
    }

Select allOpen in new window

My controller method looks like this:

   [HttpPost]
        public ActionResult Add(newRequest request)
        {
            var result = new { Success = "", Message = "" };
            if (!user.Admin())
                return RedirectToAction("Index", "myController");

            if (!ModelState.IsValid)
                return View(request);
            try
            {
                
                tbl_Data newData = new tbl_Data()
                {
                    field1 = request.field1
                    field2 = request.field2
                    field3 = request.field3
                    field4 = request.field4

      };

                DB.tbl_Data.Add(newData);
                DB.SaveChanges();
            }

            catch (Exception ex)
            {
                Utility util = new Utility();
                string error = util.innerExcep(ex);
                result = new { Success = "False", Message = error };
                return RedirectToAction("Index", "myController");
            }

            return RedirectToAction("Index", "MyController");
        }

Select allOpen in new window

What I need to do is check if all the fields 1-x text equals the same fields in the database and return a message to the user if they exist, then return the user to that record.  It is only a duplicate if the contents of all fields are the same as a current record.