这里是一个简单的例子，它使用了Nullables.NullableDateTime来（可选择的）保存一个人（Person）的生日。

public class Person

{

    int _id;

    string _name;

    Nullables.NullableDateTime _dateOfBirth;

    public Person()

    {

    }

    public int Id

    {

        get { return this._id; }

    }

    public string Name

    {

        get { return this._name; }

        set { this._name = value; }

    }

    public Nullables.NullableDateTime DateOfBirth

    {

        get { return this._dateOfBirth; }

        set { this._dateOfBirth = value; }

    }

}

如你所见，DateOfBirth是Nullables.NullableDateTime类型（而不是System.DateTime）。

这里是映射

%26lt;?xml version="1.0" encoding="utf-8" ?%26gt; 

%26lt;hibernate-mapping xmlns="urn:nhibernate-mapping-2.0"%26gt;

    %26lt;class name="Example.Person, Example" table="Person"%26gt;

        %26lt;id name="Id" access="field.camelcase-underscore" unsaved-value="0"%26gt;

            %26lt;generator class="native" /%26gt;

        %26lt;/id%26gt;

        %26lt;property name="Name" type="String" length="200" /%26gt;

        %26lt;property name="DateOfBirth" type="Nullables.NHibernate.NullableDateTimeType, Nullables.NHibernate" /%26gt;

    %26lt;/class%26gt;

%26lt;/hibernate-mapping%26gt;

这里是这个例子的部分代码：

Person per = new Person();

textBox1.Text = per.DateOfBirth.Value.ToString() // will throw an exception when there is no value.

textBox1.Text = per.DateOfBirth.ToString() // will work. it will return an empty string if there is no value.

textBox1.Text = (per.DateOfBirth.HasValue ? per.DateOfBirth.Value.ToShortDateString() : "Unknown") // friendly message

per.DateOfBirth = new System.DateTime(1979, 11, 8); // implicit cast from the "plain" System.DateTime.

per.DateOfBirth = new NullableDateTime(new System.DateTime(1979, 11, 8)); // the long way.

per.DateOfBirth = null; // this works.

per.DateOfBirth = NullableDateTime.Default; // this is more correct.