Question

I have the following code to populate a DataGridView

        var results = from loc in dtLocations.AsEnumerable()
                      join con in dtContacts.AsEnumerable() on (int)loc["contactid"] equals (int)con["id"]
                      select new
                      {
                          id = con["id"],
                          mpoc = loc["mpoc"],
                          directno = loc["directno"],
                          extension = loc["extension"],
                          faxno = loc["faxno"],
                          billing = con["billing"],
                          fullname = con["fullname"],
                          mobno = con["mobno"],
                          email = con["email"]
                      };

        dgv.AutoGenerateColumns = false;
        dgv.DataSource = results.ToList<object>();

But I cant read it back in when I click a cell

    private void dgvLocations_CellContentClick(object sender, DataGridViewCellEventArgs e)
    {
        DataGridView dgv = sender as DataGridView;
        ????? vals = ((List<object>)dgv.DataSource)[e.RowIndex];
        object id = vals.id;  //errors of course
    }

I can see in the Watcher panel of Visual Studio that it can determine the elements in the List, but I cant figure out the type that I need to set vals to in order to read them back again 🙁

Answer 1

It (new { .. }) introduces an anonymous type. Anonymous types cannot be specified by a statically-known (“compile time”) name.

Use a named (non-anonymous) type (where MyRow is an already defined class with the required properties):

// Put data in non-anonymous type
select new MyRow {
   id = ..,
}

// Now can use a name statically
MyRow row = (MyRow)data[rowIndex];

Also the dynamic type can be used with C#/.NET4+. Or, even ickier, object and explicit reflection. (Note that dynamic-typed expressions effectively handle the icky reflection automatically; just as with object, static typing information is still lost.)