#region License // Copyright (c) 2007 James Newton-King // // Permission is hereby granted, free of charge, to any person // obtaining a copy of this software and associated documentation // files (the "Software"), to deal in the Software without // restriction, including without limitation the rights to use, // copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the // Software is furnished to do so, subject to the following // conditions: // // The above copyright notice and this permission notice shall be // included in all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES // OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT // HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, // WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR // OTHER DEALINGS IN THE SOFTWARE. #endregion using System; using System.Collections.Generic; using System.Text; using System.Configuration; using System.Data.SqlTypes; namespace Newtonsoft.Utilities.Database { public static class DatabaseUtils { /// <summary> /// Converts specified value to nullable value. /// </summary> /// <param name="value">The value.</param> /// <returns></returns> public static T? ConvertToNullableValue<T>(object value) where T : struct { if (value == null) { return null; } else if (value == DBNull.Value) { return null; } else if (value is string && string.IsNullOrEmpty((string)value)) { return null; } else { if (!(value is T)) { try { value = Convert.ChangeType(value, typeof(T)); } catch (Exception e) { throw new ArgumentException("Value is not a valid type.", "value", e); } } return new T?((T)value); } } /// <summary> /// Determines whether the specified value is null. /// </summary> /// <param name="value">The value.</param> /// <returns> /// <c>true</c> if the specified value is null; otherwise, <c>false</c>. /// </returns> public static bool IsNull(object value) { if (value == null) return true; if (value is INullable && ((INullable)value).IsNull) return true; if (value == DBNull.Value) return true; return false; } } }