DataGrid sorting with DBNull.Value

Hi, i have problem with sorting when i have DBNull.Value in DataGrid:

<RadzenDataGrid TItem="DataRow" Data="@resultDataTable" AllowPaging="true" PageSize=@PersCardApp.Data.Common.StaticItems.GlobalParams.CountShowRows
            AllowSorting="true" ColumnWidth="200px" ContextMenu=@(args => ShowContextMenuWithItems(args)) RowSelect="@(args => currentRow = args)"
            AllowColumnReorder="true" ColumnReordered=@OnColumnReordered AllowColumnResize="true" ColumnResized=@OnColumnResized
            ShowPagingSummary=true PagingSummaryFormat="@BaseText.PagingSummaryFormat"
            EmptyText=@BaseText.DATAGRID_EMPTY_TEXT PagerHorizontalAlign="HorizontalAlign.Left" Style="height: 100%; max-width: min-content;">
    <Columns>
        @foreach (Data.Common.Settings.RadzenGridColumnSetting radzenGridColumnSetting in listRadzenGridColumns)
        {
            switch (radzenGridColumnSetting.Property)
            {
                case "birthday":
                case "position_start":
                case "organ_start":
                case "vidpust_start":
                case "organ_end":
                case "RANK_REAL_DATE":
                    <RadzenDataGridColumn Title=@radzenGridColumnSetting.Title Property=@radzenGridColumnSetting.Property TItem="DataRow" Width=@radzenGridColumnSetting.WidthValue TextAlign=@radzenGridColumnSetting.TextAlign Visible=@radzenGridColumnSetting.Visible Frozen=@radzenGridColumnSetting.Frozen>
                        <Template Context="data">
                            @(data[radzenGridColumnSetting.Property] == DBNull.Value ? string.Empty : Convert.ToDateTime(data[radzenGridColumnSetting.Property]).ToString("dd.MM.yyyy"))
                        </Template>
                    </RadzenDataGridColumn>
                    break;
                default:
                    <RadzenDataGridColumn Title=@radzenGridColumnSetting.Title Property=@radzenGridColumnSetting.Property TItem="DataRow" Width=@radzenGridColumnSetting.WidthValue TextAlign=@radzenGridColumnSetting.TextAlign Visible=@radzenGridColumnSetting.Visible Frozen=@radzenGridColumnSetting.Frozen>
                        <Template Context="data">
                            @data[radzenGridColumnSetting.Property]
                        </Template>
                    </RadzenDataGridColumn>
                    break;
            }
        }
    </Columns>
</RadzenDataGrid>

And when i try to sort column which contain DBNull.Value i have caught this error:
image

Is it possible to fix this without changing all DBNull.Value to some other type?