Question

I’ve got an object which I create out of an entity(T) using reflection. The object is my implementation of a table. It holds a list of columns, and I extract their properties from the entity using reflection :

  public class Generic_Table<T> : Table 
  {        
      ...// in ctor 
      type = this.GetType().GetGenericArguments()[0]; // type of T 
      BuildColumns(type); 

      private void BuildColumns(Type type)
      {
          PropertyInfo[] properties = type.GetProperties();

          Columns = new KeyValuePair<string, Type>[properties.Count()];
          int i = 0;
          foreach (PropertyInfo property in properties)
          {
              Columns[i++] = new KeyValuePair<string, Type>(property.Name, property.PropertyType);                
          }
      } 

I’m looking for a way to cast the PropertyType value as a nullable type, so that the Type value in columns would be int? if, for example, some property has int for its
PropertyType value.

Answer 1

This will do what you need:

Type nullableType = typeof(Nullable<>).MakeGenericType(property.PropertyType);

The MakeGenericType method accepts a params array of the generic type arguments. See the documentation for more details:

• http://msdn.microsoft.com/en-us/library/system.type.makegenerictype.aspx

Also, this article has a good example of something similar to what you’re doing here:

• http://msdn.microsoft.com/en-us/library/b8ytshk6.aspx