1: /// <summary>

   2: /// Set private field on passed instance (includes readonly fields)

   3: /// </summary>

   4: /// <typeparam name="TInstance">Type of instance</typeparam>

   5: /// <typeparam name="TField">Type of field</typeparam>

   6: /// <param name="instance">Instance to set private field on</param>

   7: /// <param name="fieldName">Field name</param>

   8: /// <param name="fieldValue">Value to set on field</param>

   9: public static void SetPrivateField<TInstance, TField>(TInstance instance, string fieldName, TField fieldValue)

  10: {

  11:     var fieldInfo =

  12:         instance.GetType().GetFields(BindingFlags.NonPublic | BindingFlags.Instance).Where(

  13:             f => f.Name == fieldName).FirstOrDefault();

  14:  

  15:     if (fieldInfo == null)

  16:     {

  17:         throw new InvalidOperationException(string.Format(

  18:             "Cannot find field named '{0}' on type '{1}'.", fieldName, typeof(TInstance)));

  19:     }

  20:  

  21:     if (fieldInfo.FieldType.Name != typeof(TField).Name)

  22:     {

  23:         throw new InvalidOperationException(string.Format(

  24:             "Field named '{0}' has a different type '{1}' from the one expected '{2}'",

  25:             fieldName,

  26:             fieldInfo.FieldType.Name,

  27:             typeof(TField).Name));

  28:     }

  29:  

  30:     fieldInfo.SetValue(instance, fieldValue);

  31: }