public static void SaveSingleVCardAsVcf(string directoryPath)
{
const string vcfExtension = ".vcf";
// Note that argument validation and exception handling is completely omitted in this
// example. The following "if" statement only ensures, that the method doesn't destroy
// valueable data.
if (Directory.GetFiles(directoryPath).Any(x => x.EndsWith(vcfExtension, StringComparison.OrdinalIgnoreCase)))
{
Console.WriteLine("The method \"SaveSingleVCardAsVcf(string)\" could not be executed");
Console.WriteLine("because the destination directory contains .VCF files, that might");
Console.WriteLine("be overwritten.");
return;
}
// Initialize a group vCard with composers names and live dates:
var members = new VC::RelationVCardProperty[]
{
new VC::RelationVCardProperty(InitializeComposerVCard(
"Sergei Rachmaninoff", new DateTime(1873, 4, 1), new DateTime(1943, 3, 28))),
new VC::RelationVCardProperty(InitializeComposerVCard(
"Ludwig van Beethoven", new DateTime(1770, 12, 17), new DateTime(1827, 3, 26))),
new VC::RelationVCardProperty(InitializeComposerVCard(
"Frédéric Chopin", new DateTime(1810, 3, 1), new DateTime(1849, 10, 17)))
};
var composersVCard = new VCard
{
DisplayNames = new VC::TextProperty("Composers"),
Kind = new VC::KindProperty(VC::Enums.VCdKind.Group),
Members = members
};
// Replace the embedded VCards in composersVCard.Members with Guid references in order
// to save them as separate vCard 4.0 .VCF files.
// IMPORTANT: Never call ReferenceVCards() if you intend to serialize a vCard 2.1 or vCard 3.0 !
IEnumerable <VCard> referenced = composersVCard.ReferenceVCards();
// (The extension method can be called on a single VCard because VCard implements IEnumerable<VCard>.)
Console.WriteLine();
Console.WriteLine($"After ReferenceVCards() vCardList contains {referenced.Count()} VCard objects.");
Console.WriteLine();
Console.WriteLine("composersVCard:");
Console.WriteLine();
Console.WriteLine(
referenced
.Where(x => x.DisplayNames?.Any(x => StringComparer.Ordinal.Equals(x?.Value, "Composers")) ?? false)
.First()
.ToVcfString(VC::Enums.VCdVersion.V4_0));
// Make sure to save ALL VCard objects in referenced - otherwise the information
// originally stored in composersVCard will be irrevocably lost.
foreach (VCard vcard in referenced)
{
string fileName = Path.Combine(
directoryPath,
$"{vcard.DisplayNames!.First()!.Value}{vcfExtension}");
vcard.SaveVcf(fileName, VC::Enums.VCdVersion.V4_0);
}
// Reload the .VCF files:
var vCardList = new List <VCard>();
foreach (string fileName in Directory.EnumerateFiles(directoryPath, $"*{vcfExtension}"))
{
vCardList.AddRange(VCard.LoadVcf(fileName));
}
// Make the reloaded VCard objects searchable:
IEnumerable <VCard> dereferenced = vCardList.DereferenceVCards();
// Find the parsed result from "Composers.vcf":
composersVCard = dereferenced.FirstOrDefault(x => x.DisplayNames?.Any(x => x?.Value == "Composers") ?? false);
if (composersVCard is null)
{
Console.WriteLine("Composers.vcf not found!");
}
else
{
//Retrieve Beethovens birth year from the members of the "Composers.vcf" group:
Console.Write("What year was Beethoven born?: ");
DateTimeOffset?birthDay = composersVCard.Members?
.Select(x => x as VC::RelationVCardProperty)
.Where(x => x?.Value != null)
.Select(x => x !.Value)
.FirstOrDefault(x => x !.DisplayNames?.Any(x => x?.Value == "Ludwig van Beethoven") ?? false)?
.BirthDayViews?
.Select(x => x as VC::DateTimeOffsetProperty)
.Where(x => x != null && !x.IsEmpty)
.FirstOrDefault()?
.Value;
Console.WriteLine(birthDay.HasValue ? birthDay.Value.Year.ToString() : "Don't know.");
}
}