How to bound a DataGridViewComboBoxColumn to a object?

Question

I'm trying to bound a DataGridViewComboBoxColumn to an instance of Foo, but when i set a value on the grid i got a ArgumentException telling me that i can not convert from String to Foo.

var data = (from item in someTable
            select new { Foo = item.foo, Bar = item.Bar }).ToList();
grid.DataSource = data;
column.DataPropertyName = "Foo";
column.DataSource = (from foo in Foo select foo).ToList (); //foo is an instance of Foo
column.DisplayMember = "SomeNameField"; //Foo.SomeNameField contains a description of the instance

Am i missing something? is it possible to databind to a complex object?

UPDATE:

I implemented a TypeConverter and overrided CanConvertFrom, CanConvertTo, ConvertTo, ConvertFrom. Now i'm getting

FormatException: The DataGridViewComboBoxCell value is not valid

Any ideas?

Answer 1

You are missing a possible piece.

column.DataPropertyName = "Foo";
column.DisplayMember = "SomeNameField"; 
column.ValueMember = "Bar"; // must do this, empty string causes it to be 
                            // of type string, basically the display value
                            // probably a bug in .NET
column.DataSource = from foo in Foo select foo;
grid.DataSource = data;

UPDATE:

Actually, after reading your question again, I think you are facing that noted bug. There is unfortunately no way to make it return the bound object without using a custom TypeDescriptor/TypeConverter/BindingSource.

Answer for binding to a complex object. No by default. I wrote quite a nice one for my current project. This involves making a custom TypeDescriptor/TypeConverter/BindingSource that returns all the nested properties. Another 'bug', you cant use '.' for a member separator, I had to resort to ':' instead.