public ColumnConverter()
{
Type underlyingType = IsNullableType(typeof(TColumn)) ? GetUnderlyingType(typeof(TColumn)) : typeof(TColumn);
if (RetrieveColumnMethodNamesMap.ContainsKey(underlyingType))
{
this.columnSetter = CreateSetColumnDelegate();
this.columnRetriever = CreateRetrieveColumnDelegate();
this.coltyp = ColumnTypeMap[underlyingType];
}
#if ESENTCOLLECTIONS_SUPPORTS_SERIALIZATION
else if (IsSerializable(typeof(TColumn)))
{
this.columnSetter = (s, t, c, o) => Api.SerializeObjectToColumn(s, t, c, o);
this.columnRetriever = (s, t, c) => (TColumn)Api.DeserializeObjectFromColumn(s, t, c);
this.coltyp = JET_coltyp.LongBinary;
}
#endif
else
{
throw new ArgumentOutOfRangeException("TColumn", typeof(TColumn), "Not supported for SetColumn");
}
// Compile the new delegates.
RuntimeHelpers.PrepareDelegate(this.columnSetter);
RuntimeHelpers.PrepareDelegate(this.columnRetriever);
}
/// <summary>
/// Creates a delegate which takes a nullable object and wraps the
/// non-nullable SetColumn method.
/// </summary>
/// <typeparam name="T">The type that will be nullable.</typeparam>
/// <param name="wrappedSetColumn">The (non-nullable) delegrate to wrap.</param>
/// <returns>
/// A SetColumnDelegate that takes a Nullable<typeparamref name="T"/> and
/// either sets the column to null or calls the wrapped delegate.
/// </returns>
private static SetColumnDelegate MakeNullableSetColumn <T>(SetColumnDelegate wrappedSetColumn) where T : struct
{
return((s, t, c, o) =>
{
if (((T?)o).HasValue)
{
wrappedSetColumn(s, t, c, o);
}
else
{
Api.SetColumn(s, t, c, null);
}
});
}
/// <summary>
/// Initializes a new instance of the ColumnConverter class.
/// </summary>
/// <param name="type">The type to convert to/from.</param>
public ColumnConverter(Type type)
{
if (null == type)
{
throw new ArgumentNullException("type");
}
if (!SetColumnDelegates.ContainsKey(type))
{
if (!IsSerializable(type))
{
throw new ArgumentOutOfRangeException("type", type, "Not supported for SetColumn");
}
this.setColumn = (s, t, c, o) => Api.SerializeObjectToColumn(s, t, c, o);
}
else
{
this.setColumn = SetColumnDelegates[type];
}
if (!RetrieveColumnDelegates.ContainsKey(type))
{
if (!IsSerializable(type))
{
throw new ArgumentOutOfRangeException("type", type, "Not supported for RetrieveColumn");
}
this.retrieveColumn = (s, t, c) => Api.DeserializeObjectFromColumn(s, t, c);
}
else
{
this.retrieveColumn = RetrieveColumnDelegates[type];
}
if (!Coltyps.ContainsKey(type))
{
if (!IsSerializable(type))
{
throw new ArgumentOutOfRangeException("type", type, "Has no matching ESENT column type");
}
this.coltyp = JET_coltyp.LongBinary;
}
else
{
this.coltyp = Coltyps[type];
}
}
