How can I programmatically group when binding to ExpandoObject data?

[Kenneth]

I'm trying to define pre-set groupings for my data on known columns in my dataset. But whenever I try and set the @ref property on the TelerikGrid I get the following build error. 

I've defined the TelerikGrid object in the @code section

TelerikGrid<List<ExpandoObject>>? Grid { get; set; } 

I've declared the Data property on the TelerikGrid as being bound to List<ExpandoObject>

            @if (model is not null && model.DegradeTableRows is not null && model.DegradeTableRows.Any())
            {
                <TelerikGrid 
                    Data="@model.DegradeTableRows" 
                    Width="100%"
                    Height="100%"
                    Groupable="true"
                    Pageable="false" 
                    Sortable="true"
                    FilterMode="@GridFilterMode.FilterMenu">
                    <GridAggregates>
                        <GridAggregate Field="Total Pieces" FieldType="@typeof(decimal)" Aggregate="@GridAggregateType.Sum"/>
                        <GridAggregate Field="Total % Total" FieldType="@typeof(decimal)" Aggregate="@GridAggregateType.Sum"/>
                    </GridAggregates>
                    <GridColumns>
                        <GridColumn Field="category" Width="110px" FieldType="@typeof(string)" Title="Category"/>
                        <GridColumn Field="month" Width="100px" Title="Month" FieldType="@typeof(DateTime)" DisplayFormat="{0:d}"/>
                        <GridColumn Field="rank" Width="80px" FieldType="@typeof(int)" Title="Rank"/>
                        <GridColumn Field="reason" FieldType="@typeof(string)" Title="Reason"/>
                        @if (LengthColumnNames is not null && LengthColumnNames.Any())
                        {
                            foreach (var lengthColumnName in LengthColumnNames)
                            {
                                <GridColumn Width="75px" Field="@lengthColumnName" FieldType="@typeof(decimal)" Title="@lengthColumnName"/>
                            }    
                        }
                        <GridColumn Field="Total Pieces" FieldType="@typeof(decimal)" Title="Total Pieces"/>
                        <GridColumn Field="Total % Total" FieldType="@typeof(decimal)" Title="Total % Total"/>
                    </GridColumns>
                </TelerikGrid>
            }

So I don't know why I'm getting the errors when I try to build.

I'd need to group the data when the grid comes up

                var desiredState = new GridState<List<ExpandoObject>>()
                {
                    GroupDescriptors = new List<GroupDescriptor>()
                    {
                        new GroupDescriptor()
                        {
                            Member = "month",
                            MemberType = typeof(DateTime)
                        }
                    } // end new list of group descriptors
                }; // end new grid state
                if (Grid is not null)
                {
                    await Grid.SetState(desiredState);
                }

If I add the @ref="@Grid" property to the Grid definition, I get the build error. I can comment out the code to set the group state and I still get the build error. 

Is there a way around this?

[Marin Bratanov]

Have you tries using "object" as the TItem when grouping with OnRead like explained here?