dynamic property access for generated LINQ Classes

Question

How can I access dynamically properties from a generated LINQ class ?

Cause I would like to be able to customize the displayed table columns where Partner is the LINQ Class generated from a SQL Server Database Table.

<table class="grid">
  <thead>
   <tr>
     <% foreach (Column c in (IEnumerable)ViewData["columns"]) { %>
     <th><%= c.Title %></th>    
     <% } %>                               
   </tr>
 </thead>
 <tbody>
 <% foreach (Partner p in (IEnumerable)ViewData.Model) { %>
   <tr>
     <% foreach (Column c in (IEnumerable)ViewData["columns"]) { %>
?????   <th> <%= p.GetProperty(c.Name) %>  </th>  ?????
     <% } %>         
   </tr>       
 <% } %>
  </tbody>
</table>

Any idea how the code of the "p.GetProperty(c.Name)" method could look like ?

Forgive me if the Question is very simple but as I'm new to C# and LINQ I really couldnt figure it out.

Answer 1

I believe the following will accomplish what you want:

p.GetType().GetProperty(c.Name).GetValue(p)

Answer 2

Reflection should provide what you want - in particular,

typeof(Partner).GetProperty(c.Name).GetValue(p, null)

However, you might want to do this before the loop:

var columns = (IEnumerable<string>)ViewData["columns"];
var cols = columns.Select(colName =>
      typeof(Partner).GetProperty(colName)).ToList();

This gives you a set of re-usable PropertyInfo instances that you can use per row:

 foreach (var col in cols) { %>
     <th><%= col.GetValue(p,null) %></th>
 <% }

(should that <th/> be a <td/>, by the way?)

That should be a bit more efficient than repeatedly finding each property. There are other ways of doing this too (faster again).

Answer 3

Reflection is a pretty good fit here, but really - everything is known at compile time. So it's possible to specify everything at design time.

public class DataItem
{
  string Title {get;set;}
  object Value {get;set;}
}

public interface IDataItems
{
  IEnumerable<DataItem> Items()
}


//suppose LINQ gives you this:
public partial class Customer
{
  public string Name {get;set;}
  public string Address {get;set;}
  public int Age {get;set;}
}

//then you add this in another file.
//if there's a lot of this, it can be code genned by design-time reflection
public partial class Customer : IDataItems
{
  public IEnumerable<DataItem> IDataItems.Items()
  {
    yield return new DataItem() {"Name", Name};
    yield return new DataItem() {"Address", Address};
    yield return new DataItem() {"Age", Age};
  }
}

//and the foreach loops look like this:
foreach(DataItem d in ViewData.OfType<IDataItems>().First().Items())
{
  d.Title;
}

foreach(IDataItems container in ViewData.OfType<IDataItems>())
{
    foreach(DataItem d in container.Items())
    {
       d.Value;
    }
}