/// <summary>
/// Handle the DBNull instance values returned by a <see cref="IDataReader"/> properly.
/// </summary>
/// <param name="reader">Provide the <see cref="IDataReader"/> instance</param>
/// <param name="fieldIndex">Provide the database field index</param>
/// <param name="defaultValueIfNull">Provide the value you want to get back, if the original
/// value is null or a instance of <seealso cref="DBNull">DBNull</seealso>.</param>
/// <returns>Either the provided value parameter itself or the default value.</returns>
/// <exception cref="ArgumentNullException">If reader is null</exception>
/// <exception cref="IndexOutOfRangeException">If the <paramref name="fieldIndex"/> is out of range</exception>
public static string Parse([NotNull] IDataReader reader, int fieldIndex, string defaultValueIfNull = null)
{
reader.ExceptionIfNull("reader");
var theValue = WrappedGetValueByIndex(reader, fieldIndex);
var nullable = DbObjectValueParser.SafeParseString(theValue, fieldIndex);
return(nullable ?? defaultValueIfNull);
}
/// <summary>
/// Handle the DBNull instance values returned by a <see cref="IDataReader"/> properly.
/// </summary>
/// <param name="reader">Provide the <see cref="IDataReader"/> instance</param>
/// <param name="fieldName">Provide the database field name</param>
/// <param name="defaultValueIfNull">Provide the value you want to get back, if the original
/// value is null or a instance of <seealso cref="DBNull">DBNull</seealso>.</param>
/// <returns>Either the provided value parameter itself or the default value.</returns>
/// <exception cref="ArgumentNullException">If reader or <paramref name="fieldName"/> is null/empty</exception>
/// <exception cref="ArgumentOutOfRangeException">If the <paramref name="fieldName"/> is not member of the resultset</exception>
public static string Parse([NotNull] IDataReader reader, [NotNull] string fieldName, string defaultValueIfNull = null)
{
reader.ExceptionIfNull("reader");
fieldName.ExceptionIfNullOrEmpty("fieldName");
var theValue = WrappedGetValueByName(reader, fieldName);
var nullable = DbObjectValueParser.SafeParseString(theValue, fieldName);
return(nullable ?? defaultValueIfNull);
}
/// <summary>
/// Parses the specified value for string content.
/// </summary>
/// <param name="value">The value.</param>
/// <param name="defaultValueIfNull">The default value.</param>
/// <returns></returns>
public static string ParseValue(object value, string defaultValueIfNull = null)
{
return(DbObjectValueParser.SafeParseString(value, defaultValueIfNull));
}
private static T SwitchParserByType <T>(object value, object fieldInfo, T defaultValueIfNull) where T : struct
{
object dv = defaultValueIfNull;
// most common types first:
switch (Type.GetTypeCode(typeof(T)))
{
case TypeCode.Int32:
{
var nullable = DbObjectValueParser.SafeParseNullableInt32(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.Int64:
{
var nullable = DbObjectValueParser.SafeParseNullableInt64(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.Double:
{
var nullable = DbObjectValueParser.SafeParseNullableDouble(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.Single:
{
var nullable = DbObjectValueParser.SafeParseNullableSingle(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.Decimal:
{
var nullable = DbObjectValueParser.SafeParseNullableDecimal(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.Boolean:
{
var nullable = DbObjectValueParser.SafeParseNullableBoolean(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.UInt64:
{
var nullable = DbObjectValueParser.SafeParseNullableUInt64(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.UInt32:
{
var nullable = DbObjectValueParser.SafeParseNullableUInt32(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.Int16:
{
var nullable = DbObjectValueParser.SafeParseNullableInt16(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.UInt16:
{
var nullable = DbObjectValueParser.SafeParseNullableUInt16(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.Byte:
{
var nullable = DbObjectValueParser.SafeParseNullableByte(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
case TypeCode.SByte:
{
var nullable = DbObjectValueParser.SafeParseNullableSByte(value, fieldInfo);
return(nullable.HasValue ? (T)(IConvertible)nullable.Value : defaultValueIfNull);
}
default:
{
#pragma warning disable 184
if (typeof(T) is Enum)
#pragma warning restore 184
{
// ReSharper disable HeuristicUnreachableCode
return((T)(IConvertible)DbObjectValueParser.SafeParseEnum(value, (Enum)dv, fieldInfo, false));
// ReSharper restore HeuristicUnreachableCode
}
if (typeof(T) == typeof(DateTime))
{
var nullable = DbObjectValueParser.SafeParseNullableDateTime(value, fieldInfo);
return(nullable != null ? (T)(IConvertible)nullable : defaultValueIfNull);
}
//TODO:??
if (typeof(T) == typeof(DbDate))
{
var nullable = DbObjectValueParser.SafeParseNullableDate(value, fieldInfo);
return(nullable.HasValue ? (T)(object)nullable.Value : defaultValueIfNull);
}
if (typeof(T) == typeof(DbTime))
{
var nullable = DbObjectValueParser.SafeParseNullableTime(value, fieldInfo);
return(nullable.HasValue ? (T)(object)nullable.Value : defaultValueIfNull);
}
throw new NotImplementedException("SwitchParserByType<" + typeof(T).Name + ">(value) not (yet) implemented");
}
}
}
