IEnumerableExtensionConcatWithTSource Method

Concatenates two sequences of VCardProperty objects. (Most VCardProperty ojects implement IEnumerable<VCardPoperty> and are themselves such a sequence.)

Definition

Namespace: FolkerKinzel.VCards.Extensions
Assembly: FolkerKinzel.VCards (in FolkerKinzel.VCards.dll) Version: 8.0.1+a91cc3f0fd39aeb548e16006a60ca9dd10a304a2

public static IEnumerable<TSource> ConcatWith<TSource>(
	this IEnumerable<TSource>? first,
	IEnumerable<TSource>? second
)
where TSource : VCardProperty

<ExtensionAttribute>
Public Shared Function ConcatWith(Of TSource As VCardProperty) ( 
	first As IEnumerable(Of TSource),
	second As IEnumerable(Of TSource)
) As IEnumerable(Of TSource)

C++

public:
[ExtensionAttribute]
generic<typename TSource>
where TSource : VCardProperty
static IEnumerable<TSource>^ ConcatWith(
	IEnumerable<TSource>^ first, 
	IEnumerable<TSource>^ second
)

[<ExtensionAttribute>]
static member ConcatWith : 
        first : IEnumerable<'TSource> * 
        second : IEnumerable<'TSource> -> IEnumerable<'TSource>  when 'TSource : VCardProperty

Parameters

first IEnumerableTSource: The first sequence (or VCardProperty object) to concatenate, or null.
second IEnumerableTSource: The second sequence (or VCardProperty object) to concatenate, or null.

Type Parameters

TSource: Generic type parameter that's constrained to be a class that's derived from VCardProperty.

Return Value

IEnumerableTSource
An IEnumerableT that contains the concatenated elements of the two input sequences that are not null, or an empty collection if no such elements could be found.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerableTSource. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

Remarks

The method works similar to ConcatTSource(IEnumerableTSource, IEnumerableTSource) but differs in that it can be called on null references and in that it accepts null references as argument.

Example

using FolkerKinzel.VCards;
using FolkerKinzel.VCards.Enums;
using FolkerKinzel.VCards.Extensions;
using FolkerKinzel.VCards.Models.Properties;

namespace Examples;

public class ExtensionMethodExample
{
    public static void Example()
    {
        VCard vc = InitializeTestVCard();

        Console.WriteLine("The content of vc is:\n");
        Console.WriteLine(vc);
        Console.WriteLine("\n=====================================\n");

        // (The extension methods will do all the necerssary
        // null checking.)

        // Group properties by their group name. (Group names are
        // case insensitive.)
        Console.WriteLine("\nProperty values with the group name g1:");

        IGrouping<string?, KeyValuePair<Prop, VCardProperty>> g1Group =
            vc.Groups.First(x => x.Key == "g1");

        foreach (KeyValuePair<Prop, VCardProperty> kvp in g1Group)
        {
            Console.WriteLine("  {0}: {1}", kvp.Key, kvp.Value);
        };

        Console.WriteLine("\nDisplayNames ordered by Preference:");
        foreach (TextProperty dn in vc.DisplayNames.OrderByPref())
        {
            Console.WriteLine("  {0}", dn);
        }

        Console.WriteLine("\nThe most preferred DisplayName is: {0}", vc.DisplayNames.PrefOrNull());

        Console.WriteLine("\nDisplayNames ordered by Index:");
        foreach (TextProperty dn in vc.DisplayNames.OrderByIndex())
        {
            Console.WriteLine("  {0}", dn);
        }

        Console.WriteLine("\nThe DisplayName with the lowest Index is: {0}", vc.DisplayNames.FirstOrNull());

        // Group VCardProperties by their AltID parameter:
        Console.WriteLine("\nThe following display names mean the same in different languages:");

        IGrouping<string?, TextProperty> altIDQuery =
            vc.DisplayNames.GroupByAltID()
                           .First(x => x.Key == "@1");

        foreach (TextProperty prop in altIDQuery)
        {
            Console.WriteLine("  {0}", prop);
        }

        // Serialize the VCard as VCF. (Most of the methods of the Vcf class are also
        // available as extension methods.)
        Console.WriteLine("\nvc as vCard 3.0:\n");
        Console.WriteLine(vc.ToVcfString(options: VcfOpts.Default.Unset(VcfOpts.UpdateTimeStamp)));
    }

    private static VCard InitializeTestVCard()
    {
        return VCardBuilder
            .Create(setContactID: false)
            .DisplayNames.Add("vCard zum Testen",
                               parameters:
                               p =>
                               {
                                   p.Language = "de";
                                   p.AltID = "@1";
                                   p.Index = 2;
                               }
                             )
            .DisplayNames.Add("vCard for testing",
                               parameters:
                               p =>
                               {
                                   p.Language = "en";
                                   p.AltID = "@1";
                               }
                             )
            .DisplayNames.Add("Something else",
                               parameters: p => p.Index = 1
                             )
            // The properties of the VCard class that contain collections allow
            // null references within these collections. Extension methods undertake
            // the necessary null checking when reading these properties:
            .DisplayNames.Edit(dplayNames => dplayNames.Append(null))
            .Phones.Add("1234",
                        // The ParameterSection.PropertyClass property is of Type
                        // Nullable<PCl>. Use extension methods to edit such properties
                        // safely.
                        parameters: p => p.PropertyClass = p.PropertyClass.Set(PCl.Home),
                        group: vc => "g1"
                        )
            .TimeZones.Add("Europe/Berlin", group: vc => "G1")
            .VCard;
    }
}

/*
Console Output:

The content of vc is:

Version: 2.1

[Preference: 1]
[Language: en]
[AltID: @1]
DisplayNames: vCard for testing

[Preference: 2]
[Language: de]
[AltID: @1]
[Index: 2]
DisplayNames: vCard zum Testen

[Index: 1]
DisplayNames: Something else

[Group: G1]
TimeZones: Europe/Berlin

[PropertyClass: Home]
[Group: g1]
Phones: 1234

=====================================


Property values with the group name g1:
  Phones: 1234
  TimeZones: Europe/Berlin

DisplayNames ordered by Preference:
  vCard for testing
  vCard zum Testen
  Something else

The most preferred DisplayName is: vCard for testing

DisplayNames ordered by Index:
  Something else
  vCard zum Testen
  vCard for testing

The DisplayName with the lowest Index is: Something else

The following display names mean the same in different languages:
  vCard for testing
  vCard zum Testen

vc as vCard 3.0:

BEGIN:VCARD
VERSION:3.0
G1.TZ:+01:00
FN;LANGUAGE=en:vCard for testing
N:?;;;;
g1.TEL;TYPE=HOME:1234
END:VCARD
 */