Tracking Changes

The CollectionView class can keep track of changes made to the data. It is useful in situations where you must submit changes to the server. To turn on change tracking, set the TrackChanges property to true. Once you do that, the CollectionView starts tracking the changes made to the data and exposes them using the following:

• ItemsEdited: This list contains items that are edited using the BeginEdit and CommitEdit methods.
• ItemsAdded: This list contains items that are added using the AddNew and CommitNew methods.
• ItemsRemoved: This list contains items that are removed using the Remove method.

type=note

Make sure that the DisableServerRead property of ItemSource is set to True if filtering, paging, sorting is to be performed on data available at client side only.

The example uses C1NWind data source, for which the configuration in the Quick Start application. The following image shows how the FlexGrid appears after the TrackChanges property is set to true.

The following code example demonstrates how to initialize a FlexGrid, and keep a track of changes by using TrackChanges property of the CollectionView.

TrackChangesController.cs

private C1NWindEntities db = new C1NWindEntities();
public ActionResult Index()
{
    return View(db);
}

TrackChanges.cshtml

ASP.NET

<h5>Change the data here</h5>
@(Html.C1().FlexGrid().Id("tcMainGrid").AutoGenerateColumns(false)
    .AllowAddNew(true).AllowDelete(true)
    .Columns(columns => columns
        .Add(c => c.Binding("CategoryID"))
        .Add(c => c.Binding("CategoryName"))
        .Add(c => c.Binding("Description").Width("*")))
    .Bind(ib =>
        ib.Bind(Model.Categories).DisableServerRead(true)
        )
)
<h5>See the changes here</h5>
<h6>Items edited:</h6>
@(Html.C1().FlexGrid().Id("tcEditedGrid").AutoGenerateColumns(false)
    .IsReadOnly(true).Height(100)
    .Columns(columns => columns
        .Add(c => c.Binding("CategoryID").IsReadOnly(true))
        .Add(c => c.Binding("CategoryName"))
        .Add(c => c.Binding("Description").Width("*")))
)
<h6>Items added:</h6>
@(Html.C1().FlexGrid().Id("tcAddedGrid").AutoGenerateColumns(false)
    .IsReadOnly(true).Height(100)
    .Columns(columns => columns
        .Add(c => c.Binding("CategoryID").IsReadOnly(true))
        .Add(c => c.Binding("CategoryName"))
        .Add(c => c.Binding("Description").Width("*")))
)
<h6>Items removed:</h6>
@(Html.C1().FlexGrid().Id("tcRemovedGrid").AutoGenerateColumns(false)
    .IsReadOnly(true).Height(100)
    .Columns(columns => columns
        .Add(c => c.Binding("CategoryID").IsReadOnly(true))
        .Add(c => c.Binding("CategoryName"))
        .Add(c => c.Binding("Description").Width("*")))
)

JS

<script>
    $(document).ready(function () {
        //Tracking changes
        tcMainGrid = wijmo.Control.getControl('#tcMainGrid');// the flexGrid to edit the data
        tcEditedGrid = wijmo.Control.getControl('#tcEditedGrid'); // the flexGrid to record the edited items
        tcAddedGrid = wijmo.Control.getControl('#tcAddedGrid'); // the flexGrid to record the added items
        tcRemovedGrid = wijmo.Control.getControl('#tcRemovedGrid'); // the flexGrid to record the removed items
        cvTrackingChanges = tcMainGrid.itemsSource;
        tcEditedGrid.itemsSource = cvTrackingChanges.itemsEdited;
        tcAddedGrid.itemsSource = cvTrackingChanges.itemsAdded;
        tcRemovedGrid.itemsSource = cvTrackingChanges.itemsRemoved;
        // track changes of the collectionview
        cvTrackingChanges.trackChanges = true;
    });
    //Tracking changes
    var tcMainGrid = null,
        tcEditedGrid = null,
        tcAddedGrid = null,
        tcRemovedGrid = null,
        cvTrackingChanges = null;
</script>