Grid Binding to ICollection

@{
    var contactDropDown = new Syncfusion.EJ2.DropDowns.DropDownList
    {
        DataSource = Model.ContactSelectList, 
        Query = "new ej.data.Query()", 
        Fields = new Syncfusion.EJ2.DropDowns.DropDownListFieldSettings
        {
            Value = "Id", 
            Text = "ProdId"
        }, 
        AllowFiltering = true, 
        ActionComplete="contactActionComplete"
    };
}

@(Html.EJS()
      .Grid("ContactGrid")
      .DataSource(Model.Contacts)
      .ActionBegin("contactActionBegin")
      .ActionComplete("contactActionComplete")
      .EditSettings(edit => edit.AllowAdding(true).AllowDeleting(true).AllowEditing(true).Mode(EditMode.Dialog))
      .Toolbar(new List<object> {"Search", "PdfExport", "ExcelExport", "Add", "Delete"})
      .Columns(col =>
      {
          col.Field("ProdId").HeaderText("Producer ID").EditType("dropdownedit").Edit(new { @params = contactDropDown }).Add();
          col.Field("FirstName").HeaderText("First Name").Add();
          col.Field("LastName").HeaderText("Last Name").Add();
      })
      .AllowPdfExport()
      .AllowExcelExport()
      .ToolbarClick("toolBarHandler")
      .AllowSorting()
      .Render())

public class PoolViewModel
{
    public int Id { get; set; }
    
// ... Other Fields not involved with the Grid ...
    
    public ICollection<ContactViewModel> Contacts { get; set; }
    
    public ICollection<ContactViewModel> ContactSelectList { get; set; }
    
}

function contactActionBegin(args) {
    addGridItem(args, "ProdId", this.columns);
}

function addGridItem(args, visibleColumn, columns) {
    if ((args.requestType === 'beginEdit' || args.requestType === 'add')) {
        showSingleColumn(visibleColumn, columns);
    }
}

function showSingleColumn(columnName, columns) {
    for (var i = 0; i < columns.length; i++) {
        if (columns[i].field != columnName) {
            columns[i].visible = false;
        }
        else {
            columns[i].visible = true;
        }
    }
}

function contactActionComplete(args) {
    if (args.requestType === 'save') {
        showAllColumns(this.columns);

        $.ajax({
            async: false,
            type: 'GET',
            url: '****Intentionally Hidden***' + args.data.ProdId,
            dataType: 'json',
            success: function (data) {
                args.data.ProdId = data.ProdId;
                args.data.FirstName = data.FirstName;
                args.data.LastName = data.LastName;
            }
        });        

        refreshGrid("ContactGrid");
    }
}

function showAllColumns(columns) {
    for (var i = 0; i < columns.length; i++) {
        columns[i].visible = true;
    }
}