MetaChildrenColumn not created when using a DomainService with a one to Many Mapping

Question

User-1637241392 posted

I am using the Entity Framework and a Domain Service  and I have a one-to-many mapping between two tables

I am trying to use the Dynamic Child grid example by Steve Naughton but My Data column is an EntityCollection rathen than a MetaChildrenColumn.

Has anyone got an equivalent  solution 

 var metaChildColumn = Column as MetaChildrenColumn; (this is where it is falling over as my column is an EntityCollection)

var metaForeignKeyColumn = metaChildColumn.ColumnInOtherTable as MetaForeignKeyColumn;

    if (metaChildColumn != null && metaForeignKeyColumn != null)
    {
        GridDataSource.DomainServiceTypeName = typeof(DomainService).FullName;
         MetaTable table = metaChildColumn.ChildTable;

If I just try and use the EntityCollection then it is strongly typed to the actual child entity and I am looking for a more generic solution.

Has anyone come across this and found an equivalent solution?

Thanks

Answer 1

User-330204900 posted

Hi Sophie, (I tried to e-mail you but i am in france at the moment ad can't send for some reason.), sorry I don’t as MS have not adding the insert and update parameters to the DomainServiceDataSource, I may have a way of getting it to work but not had the time to try it out.

 

Just in case you want to try yourself I was thinking of adding on inserting and on updating event to the child grid see the EF ManyToMany_Edit field template for how to do that and then add the parameters there J

Answer 2

User-1637241392 posted

Hi there, I have found a generic way of doing this though so far only for Viewing - I have not tried updating the gridview yet.

This is how I managed to get it to work.

 public partial class ChildGrid : FieldTemplateUserControl
    {
        protected MetaTable DisplayTable { get; set; }
        private String[] DisplayColumns { get; set; }
        private String DisplayTableName { get; set; }


        protected void Page_Init(object sender, EventArgs e)
        {
            var attribute = Column.Attributes.OfType<ShowChildColumnsAttribute>().SingleOrDefault();

 
            if (attribute != null)
            {
                if (attribute.DisplayColumns.Length > 0)
                    DisplayColumns = attribute.DisplayColumns;

                DisplayTableName = attribute.TableName;
            }
            DisplayTable = Column.Table.Model.GetTable(DisplayTableName);
            GridView1.ColumnsGenerator = new FieldTemplateRowGenerator(DisplayTable, DisplayColumns);

            // setup the GridViewDataKeys

            var keys = new String[DisplayTable.PrimaryKeyColumns.Count];
            int i = 0;
            foreach (var keyColumn in DisplayTable.PrimaryKeyColumns)
            {
                keys[i] = keyColumn.Name;
                i++;
            }
            GridView1.DataKeyNames = keys;
            GridView1.SetMetaTable(DisplayTable);

        }

        protected override void OnDataBinding(EventArgs e)
        {
            // Get the real entity from the wrapper
            object entity = Row;

            // Get the collection of reservations for this customer and make sure it's loaded
            var entityCollection = (RelatedEnd) Column.EntityTypeProperty.GetValue(entity, null);

            entityCollection.Load();

            var objectQuery = (ObjectQuery) entityCollection.GetType().GetMethod(
                "CreateSourceQuery").Invoke(entityCollection, null);
            
            GridView1.DataSource = objectQuery;

        }


       // use this to navigate to the Details page for our Child Grid
       // gets the primary keys from the grid datakeys and uses these to
       // navigate to the details page for the table in question
        
        protected void GridSelectedIndexChanged(object sender, EventArgs e)
        {
            // Get the currently selected row using the SelectedRow property.
            string primarykeyvalues = string.Empty;

            // now let's build up the primary keys for the redirect
            if (GridView1.SelectedDataKey != null)
            {
                var keys = GridView1.SelectedDataKey.Values;

                foreach (DictionaryEntry key in keys)
                {
                    primarykeyvalues = primarykeyvalues + key.Key;
                    primarykeyvalues = primarykeyvalues + "=" + key.Value + "&";
                }
                primarykeyvalues = primarykeyvalues.TrimEnd('&', ' ');
            }
            Response.Redirect("../" + DisplayTable + "/DetailsSubGridViews.aspx?" + primarykeyvalues);
 
        }

This seems to work quite nicely so far...