// -------------------------------------------------------------------------------------------------------------------- // <copyright file="NullableValueConverter.cs" company="Catel development team"> // Copyright (c) 2008 - 2011 Catel development team. All rights reserved. // </copyright> // <summary> // Converts a value to a representive value for nullable. // </summary> // -------------------------------------------------------------------------------------------------------------------- using System; using System.Windows.Data; namespace Catel.Windows.Data.Converters { /// <summary> /// Converts a value to a representive value for nullable. /// </summary> /// <remarks>Resolves problem with databinding with nullables. When textbox hasn't a value then null is expected as return value.</remarks> #if !SILVERLIGHT [ValueConversion(typeof(object), typeof(object))] #endif public class NullableValueConverter : IValueConverter { /// <summary> /// Convert to targettype. /// </summary> /// <param name="value">A value.</param> /// <param name="targetType">Target type (only types with standard conversion are supported, System.Convert.ChangeType is used for conversion).</param> /// <param name="parameter">Parameter.</param> /// <param name="culture">A culture.</param> /// <returns>Converted value.</returns> public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { // not the interresting part for us, use default conversion return System.Convert.ChangeType(value, targetType, culture); } /// <summary> /// Convert back to nullable object. /// </summary> /// <param name="value">A value.</param> /// <param name="targetType">Target type (only types with standard conversion are supported, System.Convert.ChangeType is used for conversion).</param> /// <param name="parameter">Parameter.</param> /// <param name="culture">A culture.</param> /// <returns>Converted value.</returns> public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { object result = null; string str = value as string; if (value != null && (str == null || !string.IsNullOrEmpty(str.Trim()))) { Type underlyingType = Nullable.GetUnderlyingType(targetType) ?? targetType; try { result = System.Convert.ChangeType(value, underlyingType, culture); } catch { // ignore exceptions } } return result; } } }
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