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//------------------------------------------------------------------------------
// <copyright file="DefaultValueTypeConverter.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
// <owner current="true" primary="false">Microsoft</owner>
// <owner current="false" primary="false">Microsoft</owner>
//------------------------------------------------------------------------------
/*
*/
namespace System.Data {
using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Diagnostics;
using System.Globalization;
/// <devdoc>
/// <para>Provides a type
/// converter that can be used to populate a list box with available types.</para>
/// </devdoc>
internal sealed class DefaultValueTypeConverter : StringConverter {
private static string nullString = "<null>";
private static string dbNullString = "<DBNull>";
// converter classes should have public ctor
public DefaultValueTypeConverter() {
}
public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) {
if (destinationType == null) {
throw new ArgumentNullException("destinationType");
}
if (destinationType == typeof(string)) {
if (value == null) {
return nullString;
}
else if (value == DBNull.Value) {
return dbNullString;
}
}
return base.ConvertTo(context, culture, value, destinationType);
}
public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) {
if (value != null && value.GetType() == typeof(string)) {
string strValue = (string)value;
if (string.Compare(strValue, nullString, StringComparison.OrdinalIgnoreCase) == 0)
return null;
else if (string.Compare(strValue, dbNullString, StringComparison.OrdinalIgnoreCase) == 0)
return DBNull.Value;
}
return base.ConvertFrom(context, culture, value);
}
}
}
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