GridView - How to track changes made with an unbound CheckBox in the DataItemTemplate

This example illustrates how to:
- Define a custom editor (for example, the CheckBox) inside the column's DateItemTemplate (via the GridViewSettings.SetDataItemTemplateContent method);
- Specify the CheckBox.Name property based on the corresponding DataRow's keyValue (this operation requires specifying the GridViewSettings.KeyFieldName property);
- Subscribe the client-side ASPxClientCheckBox.CheckedChanged event;
- Store the CheckBox's state via a custom JavaScript object like a dictionary/key value pairs (the CheckBox.Name - Checked State)

An end-user is able to select/deselect the CheckBoxes displayed within the column.
When the user tries to perform any GridView's callback (sorting, paging, etc.), the stored key value pairs collection is serialized via the "toJSON" plugin (available with the jquery-json library). The serialized object is passed to a Controller as custom argument according to the "Passing Values to Controller Action Through Callbacks" technique.
The passed serialized object is de-serialized on the Controller side and passed to the View object to restore an unbound CheckBox state.

View:

[JScript]
<script type="text/javascript">var DXHiddenObject = {};function OnBeginCallback(s, e){
        e.customArgs["items"] = $.toJSON(DXHiddenObject);}function OnCheckedChanged(s, e){if(s.GetChecked())
            DXHiddenObject[s.name] = true;elsedelete DXHiddenObject[s.name];}</script>

PartialView:

C#:

[C#]
@Html.DevExpress().GridView(settings=>{settings.Name="gvTypedListDataBinding";settings.CallbackRouteValues=new{Controller="Home",Action="TypedListDataBindingPartial"};settings.KeyFieldName="ID";...settings.Columns.Add(column=>{column.SetDataItemTemplateContent(c=>{Html.DevExpress().CheckBox(checkboxSettings=>{checkboxSettings.Name="cb_"+c.KeyValue.ToString();checkboxSettings.Properties.ClientSideEvents.CheckedChanged="OnCheckedChanged";if(ViewData["items"]!=null){Dictionary<string,bool>items=(Dictionary<string,bool>)ViewData["items"];checkboxSettings.Checked=items.ContainsKey(checkboxSettings.Name)&&(bool)items[checkboxSettings.Name];}}).Render();});});settings.ClientSideEvents.BeginCallback="OnBeginCallback";}).Bind(Model).GetHtml()

VB.NET:

[VB.NET]
@Html.DevExpress().GridView( _Sub(settings)
            settings.Name = "gvTypedListDataBinding"
            settings.CallbackRouteValues = NewWith {Key .Controller = "Home", Key .Action = "TypedListDataBindingPartial"}
            settings.KeyFieldName = "ID"
            ...
            settings.Columns.Add( _Sub(column)
                        column.SetDataItemTemplateContent( _Sub(c)
                                    Html.DevExpress().CheckBox( _Sub(checkboxSettings)
                                                checkboxSettings.Name = "cb_" + c.KeyValue.ToString()
                                                checkboxSettings.Properties.ClientSideEvents.CheckedChanged = "OnCheckedChanged"If (ViewData("items") IsNot Nothing) ThenDim items As Dictionary(OfString, Boolean) = CType(ViewData("items"), Dictionary(OfString, Boolean))
                                                    checkboxSettings.Checked = items.ContainsKey(checkboxSettings.Name) AndAlsoCBool(items(checkboxSettings.Name))EndIfEndSub).Render()EndSub)EndSub)

            settings.ClientSideEvents.BeginCallback = "OnBeginCallback"EndSub).Bind(Model).GetHtml()

Controller:

[C#]
publicclassHomeController:Controller{publicActionResultIndex(){if(Session["TypedListModel"]==null)Session["TypedListModel"]=InMemoryModel.GetTypedListModel();returnView(Session["TypedListModel"]);}publicActionResultTypedListDataBindingPartial(){ViewData["items"]=GetSerializedObject(Request["items"]);returnPartialView(Session["TypedListModel"]);}privateDictionary<string,bool>GetSerializedObject(stringinputString){if(string.IsNullOrEmpty(inputString))returnnull;Dictionary<string,bool>items=null;try{items=newJavaScriptSerializer().Deserialize<Dictionary<string,bool>>(inputString);}catch{ViewData["ErrorMessage"]="Invalid Input JSON String";}returnitems;}}

VB.NET

[VB.NET]
PublicClass HomeControllerInherits ControllerPublicFunction Index() As ActionResultIf Session("TypedListModel") IsNothingThen
            Session("TypedListModel") = InMemoryModel.GetTypedListModel()EndIfReturn View(Session("TypedListModel"))EndFunctionPublicFunction TypedListDataBindingPartial() As ActionResult
        ViewData("items") = GetSerializedObject(Request("items"))Return PartialView(Session("TypedListModel"))EndFunctionPrivateFunction GetSerializedObject(ByVal inputString AsString) As Dictionary(OfString, Boolean)IfString.IsNullOrEmpty(inputString) ThenReturnNothingEndIfDim items As Dictionary(OfString, Boolean) = NothingTry
            items = New JavaScriptSerializer().Deserialize(Of Dictionary(OfString, Boolean))(inputString)Catch
            ViewData("ErrorMessage") = "Invalid Input JSON String"EndTryReturn itemsEndFunctionEndClass