使用MVVM将行附加到WPF中的Datagrid

Question

I have a DataGrid in my View as shown below.,

My Question is how can I Append the values from the textboxes to the row datagrid

I have make sure that the Model has All the properties, When I click on the Add button it overwrites the dataGrid and shows only one latest record the and my ViewModel look like this:

class BatchItemsViewModel : ViewModelBase
    {

        public SearchItemsModel msearchItems { get; set; }

        ObservableCollection<SearchItemsModel> _BatchItemsGrid;

        public ObservableCollection<SearchItemsModel> BatchItemsGrid
        {
            get { return _BatchItemsGrid; }
            set
            {
                _BatchItemsGrid = value;
                OnPropertyChanged("BatchItemsGrid");
            }
        }

        private ICommand _addDataToBatchGrid;
        public ICommand addDataToBatchGrid
        {
            get
            {
                return _addDataToBatchGrid;
            }
            set
            {
                _addDataToBatchGrid = value;
            }
        }

        public BatchItemsViewModel()
        {
            msearchItems = new SearchItemsModel();
            addDataToBatchGrid = new RelayCommand(new Action<object>(AddDataInBatchGrid));

        }


        public void AddDataInBatchGrid(object obj)
        {
            ObservableCollection<SearchItemsModel> batchGridData = new ObservableCollection<SearchItemsModel>();
            var data = new SearchItemsModel
                            {
                                BatchNumber = msearchItems.BatchNumber,
                                MFDDate = msearchItems.MFDDate,
                                ExpiryDate = msearchItems.ExpiryDate,
                                Quantity = msearchItems.Quantity,
                            };
            batchGridData.Add(data);

            BatchItemsGrid = batchGridData; // HERE I am overwriting the datagrid

            //How can I Append the batchGridData to BatchItemsGrid (BatchItemsGrid.Append(batchGridData)???)
        }

    }

NOTE: I have gone through the other threads as well in the community for the similar posts but I couldn't find the appropriate and please correct me if I am going in wrong direction.

Answer 1

public void AddDataInBatchGrid(object obj)
        {
            var data = new SearchItemsModel
                            {
                                BatchNumber = msearchItems.BatchNumber,
                                MFDDate = msearchItems.MFDDate,
                                ExpiryDate = msearchItems.ExpiryDate,
                                Quantity = msearchItems.Quantity,
                            };
            this.BatchItemsGrid.Add(data);           
        }

...Should do the trick. (don't replace the whole collection, just add items to it and let the notification events handle the UI updates)