DefaultValueTypeConverter.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / DefaultValueTypeConverter.cs / 1 / DefaultValueTypeConverter.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
// [....] 
//----------------------------------------------------------------------------- 

/* 
 */
namespace System.Data {
    using System.ComponentModel;
    using System.ComponentModel.Design.Serialization; 
    using System.Diagnostics;
    using System.Globalization; 
 
    /// 
    ///    Provides a type 
    ///       converter that can be used to populate a list box with available types.
    /// 
    internal sealed class DefaultValueTypeConverter : StringConverter {
        private static string nullString = ""; 
        private static string dbNullString = "";
 
        // 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);
        }
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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