var app = angular.module('app', ['ngTouch', 'ui.grid', 'ui.grid.expandable', 'ui.grid.selection', 'ui.grid.pinning']);

app.controller('MainCtrl', ['$scope', '$http', '$log', function ($scope, $http, $log) {
  var main = $scope;
  $scope.name = 'MainCtrl';
  $scope.mainData = [];
  $scope.subGridOptions = 
  {
    columnDefs: [ {name:"Id", field:"id"},{name:"Name", field:"name"} ]
  };
  
  $scope.expandableGridOptions = 
  {
    subGridOptions : $scope.subGridOptions
  };
  
  $scope.gridOptions = {
    expandableRowTemplate: 'expandableRowTemplate.html',
    //expandableRowHeight: 150,
    
    //subGridVariable will be available in subGrid scope
    expandableRowScope: { subGridOptionsModel : $scope.subGridOptions }
  }

  $scope.gridOptions.columnDefs = [
    { name: 'id' },
    { name: 'name'},
    { name: 'age'},
    { name: 'address.city'}
  ];

  $http.get('https://cdn.rawgit.com/angular-ui/ui-grid.info/gh-pages/data/500_complex.json')
    .success(function(data) {
      /*for(i = 0; i < data.length; i++){
        data[i].subGridOptions = {
          columnDefs: [ {name:"Id", field:"id"},{name:"Name", field:"name"} ],
          data: data[i].friends
        }
      }*/
      $scope.gridOptions.data = data;
      $scope.mainData = data;
    });


    $scope.gridOptions.onRegisterApi = function(gridApi){
      $scope.gridApi = gridApi;


      gridApi.expandable.on.rowExpandedStateChanged($scope, function (row) {
        //debugger;
          if (row.isExpanded) {
            //row.entity.subGridOptions = main.subGridOptions;
            //row.entity.subGridOptions = row.entity.subGridOptions;
            //row.entity.subGridOptions.data = row.entity.friends;
            //main.subGridOptions.data = row.entity.friends;
            
            /*row.entity.subGridOptions = {
              columnDefs: [
              { name: 'name'},
              { name: 'gender'},
              { name: 'company'}
            ]};
          
            $http.get('https://cdn.rawgit.com/angular-ui/ui-grid.info/gh-pages/data/100.json')
              .success(function(data) {
                row.entity.subGridOptions.data = data;
              });*/
          }
      });

    };

    $scope.expandAllRows = function() {
      $scope.gridApi.expandable.expandAllRows();
    }

    $scope.collapseAllRows = function() {
      $scope.gridApi.expandable.collapseAllRows();
    }
}]);

app.controller('SecondCtrl', ['$scope', '$http', '$log', function ($scope, $http, $log) {
      $scope.name = 'SecondCtrl';
  
      $scope.gridOptions = {
        enableRowSelection: true,
        expandableRowTemplate: 'expandableRowTemplate.html',
        //expandableRowHeight: 150
      }

      $scope.gridOptions.columnDefs = [
        { name: 'id', pinnedLeft:true },
        { name: 'name'},
        { name: 'age'},
        { name: 'address.city'}
      ];

      $http.get('https://cdn.rawgit.com/angular-ui/ui-grid.info/gh-pages/data/500_complex.json')
        .success(function(data) {
          for(i = 0; i < data.length; i++){
            data[i].subGridOptions = {
              columnDefs: [ {name:"Id", field:"id"},{name:"Name", field:"name"} ],
              data: data[i].friends
            }
          }
          $scope.gridOptions.data = data;
        });
    }]);
    
app.controller('ThirdCtrl', ['$scope', '$http', '$log', function ($scope, $http, $log) {
  $scope.name = 'SecondCtrl';
      $scope.gridOptions = {
        expandableRowTemplate: 'expandableRowTemplate.html',
        expandableRowHeight: 150,
        onRegisterApi: function (gridApi) {
            gridApi.selection.on.rowSelectionChanged(context.Private.Scope, function (row, event) {
                if (event.target.localName != 'i' && event.target.localName != 'a' && context.Private.gridApi.expandable != undefined)
                      context.Private.gridApi.expandable.toggleRowExpansion(row.entity);
            });

            gridApi.expandable.on.rowExpandedStateChanged($scope, function (row) {
                if (row.isExpanded) {
                  //debugger;
                  row.entity.subGridOptions = {
                    columnDefs: [
                    { name: 'name'},
                    { name: 'gender'},
                    { name: 'company'}
                  ]};
                
                  $http.get('https://cdn.rawgit.com/angular-ui/ui-grid.info/gh-pages/data/100.json')
                    .success(function(data) {
                      row.entity.subGridOptions.data = data;
                    });
                }
            });
        }
      }

      $scope.gridOptions.columnDefs = [
        { name: 'id', pinnedLeft:true },
        { name: 'name'},
        { name: 'age'},
        { name: 'address.city'}
      ];

      $http.get('https://cdn.rawgit.com/angular-ui/ui-grid.info/gh-pages/data/500_complex.json')
        .success(function(data) {
          $scope.gridOptions.data = data;
        });
    }]);

.grid {
  width: 100%;
  height: 400px;
}

<div>
  <div>
  Name : {{row.entity.registered}} Active : {{row.entity.isActive}}
  </div>
  <div>
  <!-- About : {{row.entity.about}} -->
  </div>
<div ui-grid="subGridOptionsModel" style="height:140px;"></div> 
</div>

<!doctype html>
<html ng-app="app">
  <head>
    <script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.3.4/angular.js"></script>
    <script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.3.4/angular-touch.js"></script>
    <script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.3.4/angular-animate.js"></script>
    <script src="http://localhost:9003/docs/grunt-scripts/csv.js"></script>
    <script src="http://localhost:9003/docs/grunt-scripts/pdfmake.js"></script>
    <script src="http://localhost:9003/docs/grunt-scripts/vfs_fonts.js"></script>
    <script src="https://cdn.rawgit.com/angular-ui/ui-grid.info/gh-pages/release/3.0.0-rc.19/ui-grid.js"></script>
    <link rel="stylesheet" href="https://cdn.rawgit.com/angular-ui/ui-grid.info/gh-pages/release/3.0.0-rc.19/ui-grid.css" type="text/css">
    <link rel="stylesheet" href="main.css" type="text/css">
  </head>
  <body>

<div ng-controller="MainCtrl">
  <div class="control-group">
    <input type="button" class="btn btn-small" ng-click="expandAllRows()" value="Expand All"/>
    <input type="button" class="btn btn-small" ng-click="collapseAllRows()" value="Collapse All"/>
  </div>
  <div ui-grid="gridOptions" ui-grid-pinning ui-grid-expandable class="grid"></div>
</div>
Expandable rows works with checkboxes from selection and left pins
<div ng-controller="SecondCtrl">
   <div ui-grid="gridOptions" ui-grid-pinning ui-grid-expandable ui-grid-selection class="grid"></div>
</div>
Retrieve data for subGrid when expanding
<!-- <div ng-controller="ThirdCtrl">
   <div ui-grid="gridOptions" ui-grid-expandable class="grid"></div>
</div> -->


    <script src="app.js"></script>
  </body>
</html>