SQL to Ext Grid

[m0f]

Hello friends,

I'm new here on everything which is .Net. I have experience with ExtJs, but this is my first time creating an webtool with Ext.Net and i have a little problem which i dont get how to fix it.
I have an webtool which has an TreeGrid where the data is get from the MSSQL and is populate correctly. After clicking on a child from that treegrid, an formpanel will show up with some tabs. On those tabs it will be some textfields with a gridpanel. My problem is that i can't bring the data for GridPanel. I dont understand what i'm doing wrong.
I'm using the Ext.Net v7.2.0 Classic.

I will drop below a few codes to see what i'm talking about.

Here is the GridPanel View:

                            <ext-container layout="HBox">
                                <defaults>
                                    <ext-add key="header" value="false" mode="Raw" />
                                    <ext-add key="frame" value="true" mode="Raw" />
                                    <ext-add key="width" value="100" mode="Raw" />
                                </defaults>
                                <items>


                                    <!-- Configure a GridPanel and reference the Store above -->
                                    <ext-gridPanel 
                                                    title="Grouped Header"
                                                   width="800"
                                                   height="300"
                                                   frame="true">
                                        <!-- Configure a Store -->
                                        <store>
                                            <ext-store id="Store1" data="Model.GridPanel" autoLoad="true">
                                                        <fields>
                                                            <ext-integerDataField name="CommentId"/>
                                                            <ext-integerDataField name="CompensationPeriodKey"/>
                                                            <ext-stringDataField name="Title" />
                                                            <ext-stringDataField name="Comment" />
                                                            <ext-booleanDataField name="Print" />
                                                        </fields>
                                            </ext-store>
                                        </store>
                                        <columns>
                                            <ext-column text="#" dataIndex="CommentId"  />
                                            <ext-column text="Print" dataIndex="Print" />
                                            <ext-column text="Title" dataIndex="Title" />
                                            <ext-column text="Comment" dataIndex="Comment" flex='1' />
                                        </columns>
                                        <bbar>
                                            <ext-toolbar>
                                                <items>
                                                    <ext-button text="Print" iconCls="x-md md-icon-print" handler="this.up('grid').print();" />
                                                </items>
                                            </ext-toolbar>
                                        </bbar>
                                    </ext-gridPanel>
                                </items>
                            </ext-container>

And here is the Controller:

namespace MyApp.Controllers
{
    public class Controller: Controller
    {
        public IActionResult Index(int compPeriod)
        {
            // load entity for selected key
            TREEGRID entity = null;
            using (var context = new MyDbContext())
            {
                entity = context.TREEGRID.Include(per => per.GridPanel).FirstOrDefault(per => per.DataPeriodKey == compPeriod);
            }
            return View("Index", entity);
        }
    }
}

And my return is: