title: Databinding to nested property - Cannot bind property or column (Winforms)
body: <p>We are running a .NET 4.0 application using Windows Forms. The application uses a single form for two different types of objects. </p>
  
  <pre><code>namespace NetIssue
  {
      public partial class Form1 : Form
      {
          B myObj;
          public Form1()
          {
              InitializeComponent();
  
              myObj = new B();
          }
  
          private void Form1_Load(object sender, EventArgs e)
          {
              textBox1.DataBindings.Add(new Binding("Text", myObj, "c.Message"));
          }
      }
  
      public class Comment {
          public int ID { get; set; }
          public string Message { get; set; }
  
          public Comment(string msg)
          {
              Message = msg;
          }
      }
  
      public class A {
          string MyName = "";
      }
  
      public class B : A {
          public Comment c { get; set; }
  
          public B()
          {
              c = new Comment("test");
          }
      }
  }
  </code></pre>
  
  <p>When the binding above is run in .NET 4.0, we get the error</p>
  
  <blockquote>
    <p>An error occured: Cannot bind to the property or column Message on the
    DataSource. Parameter name: dataMember</p>
  </blockquote>
  
  <p>However, if we install .NET 4.5 this error goes away. </p>
  
  <p><strong>Is this a limitation of .NET 4.0, a bug in .NET 4.0, or is something else going on?</strong></p>