I have made property editor in umbraco 7+ with angularjs by following this example - https://our.umbraco.org/documentation/tutorials/Creating-a-Property-Editor/

//ControllerCode
angular.module("umbraco")
  .controller("My.MarkdownEditorController",
  function () {
   $scope.txtName = "Hector";
  });

  ------------------

  //HTMLCode
 <div ng-controller="My.MarkdownEditorController">
 <textarea ng-model="txtName"></textarea>
 </div>

  --------------------------
    //In Manifest , i am using following alias
    alias: "My.MarkdownEditor",

Now my requirement is I want to fetch that textarea value in c# controller. How would i do it ?