可以解决DateTimePicker 无法为DBNull的代码.已经测试通过,收藏

转自 http://www.codeguru.com/csharp/csharp/cs_controls/custom/article.php/c9645/

using System;

using System.ComponentModel;

using System.Globalization;

using System.Runtime.InteropServices;

using System.Threading;

using System.Windows.Forms;

// Copyright (c) 2005 Claudio Grazioli, http://www.grazioli.ch
//

// This implementation of a nullable DateTimePicker is a new implementation

// from scratch, but it is based on ideas I took from this nullable

// DateTimePickers:

// - http://www.omnitalented.com/Blog/PermaLink,guid,9ee757fe-a3e8-46f7-ad04-ef7070934dc8.aspx
// from Alexander Shirshov

// - http://www.codeproject.com/cs/miscctrl/Nullable_DateTimePicker.asp
// from Pham Minh Tri

//

// This code is free software; you can redistribute it and/or modify it.

// However, this header must remain intact and unchanged. Additional

// information may be appended after this header. Publications based on

// this code must also include an appropriate reference.

//

// This code is distributed in the hope that it will be useful, but

// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

// or FITNESS FOR A PARTICULAR PURPOSE.

//

namespace ProjectMentor.Windows.Controls