Category Archives: Reflection

Get property values by name

Posted on by Posted in Reflection

Here are some extension methods to get the values of properties, supporting navigation of properties. For example:

  • customer.GetValueForPath(“Name”)
  • order.GetValueForPath(“Customer.Name”)

This might come in handy once in a while. (I used it to export the data displayed in a Datagrid)

  1. ///<summary>
  2. /// Gets the value for path.
  3. ///</summary>
  4. ///<param name=”obj”>The object to get the value from.</param>
  5. ///<param name=”path”>The path of the property to get (Path of property names).</param>
  6. public static object GetValueForPath(this object obj, string path)
  7. {
  8.     if (obj == null) return null;
  10.     var type = obj.GetType();
  11.     var propertyPath = type.GetPropertyPath(path);
  12.     return propertyPath == null ? null : obj.GetValueForPath(propertyPath);
  13. }
  15. ///<summary>
  16. /// Gets the value for path.
  17. ///</summary>
  18. ///<param name=”obj”>The object to get the value from.</param>
  19. ///<param name=”path”>The path of the property to get (Path of PropertyInfo’s).</param>
  20. ///<returns></returns>
  21. public static object GetValueForPath(this object obj, IEnumerable<PropertyInfo> path)
  22. {
  23.     object result = obj;
  24.     foreach (var info in path)
  25.     {
  26.         if (result == null) break;
  27.         result = info.GetValue(result, null);
  28.     }
  29.     return result;
  30. }
  33. ///<summary>
  34. /// Translates a string property path, to a list of PropertyInfo objects
  35. ///</summary>
  36. ///<param name=”type”>The type of the base object.</param>
  37. ///<param name=”path”>The path to get the PropertyInfo’s for.</param>
  38. ///<returns></returns>
  39. public static IList<PropertyInfo> GetPropertyPath(this Type type, string path)
  40. {
  41.     var propertyPath = new List<PropertyInfo>();
  42.     if (!string.IsNullOrEmpty(path))
  43.     {
  44.         var propertyNames = path.Split(‘.’);
  45.         var currentType = type;
  46.         foreach (var propertyName in propertyNames)
  47.         {
  48.             var prop = currentType.GetProperty(propertyName);
  49.             if (prop == null)
  50.             {
  51.                 Debug.WriteLine(“TypeExtensions.GetPropertyPath Error: Property ‘{0}‘ does not exist on type ‘{1}‘. In path ‘{2}‘ on type ‘{3}‘”, propertyName, currentType.Name, path, type.Name);
  52.                 break;
  53.             }
  54.             propertyPath.Add(prop);
  55.             currentType = prop.PropertyType;
  56.         }
  57.     }
  58.     return propertyPath;
  59. }

Add attributes to a property at runtime.

Posted on by Posted in Reflection, WinForms Leave a comment

In a project I had to create a little test application to create and edit objects of a referenced assembly. This was very early in the development stage, so the classes could possibly change a lot during the course of the project.

Instead of designing a UI for each class and getting into the process of changing it over and over again, I decided to use Reflection and the PropertyGrid control in winForms.

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