In my PartialView I add a grid with a column that I need to be a combobox in this way.

settings.Columns.Add(column =>
    {
        column.FieldName = "TheFieldName";
        column.Caption = ""ACaption;

        column.ColumnType = MVCxGridViewColumnType.ComboBox;
        var comboBoxProperties = column.PropertiesEdit as ComboBoxProperties;
        comboBoxProperties.DataSource = ViewData["MyListOfObjects"];
        comboBoxProperties.TextField = "Description";
        comboBoxProperties.ValueField = "Description";
        comboBoxProperties.ValueType = typeof(String);
    }); 

The ViewData is populated in the Index method of the Controller and I have checked that it is populated with objects that contain values.

The Combobox in the PopupEditForm not showing anything.

Any idea what could be wrong?

Regards.