ForeignKey_Edit Populating the DropDown with all available values

Question

User-1876416927 posted

http://forums.asp.net/t/1673340.aspx?Override+PopulateListControl+in+ForeignKey_Edit+field+template

   protected new void PopulateListControl(ListControl listControl)
        {
            var query = Column.Table.GetQuery();

            // row
            var entityParam = Expression.Parameter(Column.Table.EntityType, "row");
            // row => row.DataSourceID
            var columnLambda = Expression.Lambda(Expression.Property(entityParam, Column.EntityTypeProperty), entityParam);
            // Items.Select(row => row.DataSourceID)
            var selectCall = Expression.Call(typeof(Queryable), "Select", new Type[] { query.ElementType, columnLambda.Body.Type }, query.Expression, columnLambda);
            // Items.Select(row => row.DataSourceID).Distinct
            var distinctCall = Expression.Call(typeof(Queryable), "Distinct", new Type[] { Column.EntityTypeProperty.PropertyType }, selectCall);

            var result = query.Provider.CreateQuery(distinctCall);

Having used the code from here to populate my dropdown list I find that only values already in the parent table are being displayed in the select list.  I am new to "Expressions" how is it possible to unlink it from the parent table and display all values.  I imagine it's trivial but , as i say, I'm a bear of little brain.

Answer 1

User-330204900 posted

Hi domh, that could be the distinct just omit that and use the CreateQuery using the SelctCall :)

Answer 2

User-1876416927 posted

       using (var db = new WW1researchDataContext())
            {
                var result = db.GetTable(this.Column.Provider.ColumnType);

Hi,

Thank you for replying, I saw it's been a while since you were on this so I am most grateful for you looking at the post.

Above was the slightly more native way of doing it I discovered, unfortunately the distinct call does what it says on the tin and the link to the parent occurs elsewhere.  I imagine there is something to be done with Column.Table.Provider on the GetQuery front.  Unfortunately the lambda bits look like wizardry to me, I haven't been able to decrypt it!

Dom

Answer 3

User-330204900 posted

Email me direct and we can discuss what you are trying to achieve :)