ContentType.Boundary Property

Reference

Definition

Namespace:: System.Net.Mime

Assemblies:: netstandard.dll, System.Net.Mail.dll

Assembly:: System.Net.Mail.dll

Assembly:: System.dll

Assembly:: netstandard.dll

Source:: ContentType.cs

Source:: ContentType.cs

Source:: ContentType.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Gets or sets the value of the boundary parameter included in the Content-Type header represented by this instance.

public:
 property System::String ^ Boundary { System::String ^ get(); void set(System::String ^ value); };

public string? Boundary { get; set; }

public string Boundary { get; set; }

member this.Boundary : string with get, set

Public Property Boundary As String

Property Value

String

A String that contains the value associated with the boundary parameter.

Examples

The following code example displays the value of the Boundary property.

static void CreateMessageWithMultipleViews( String^ server, String^ recipients )
{
   
   // Create a message and set up the recipients.
   MailMessage^ message = gcnew MailMessage( L"jane@contoso.com",recipients,L"This email message has multiple views.",L"This is some plain text." );
   
   // Construct the alternate body as HTML.
   String^ body = L"<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN\">";
   body = String::Concat( body, L"<HTML><HEAD><META http-equiv=Content-Type content=\"text/html; charset=iso-8859-1\">" );
   body = String::Concat( body, L"</HEAD><BODY><DIV><FONT face=Arial color=#ff0000 size=2>this is some HTML text" );
   body = String::Concat( body, L"</FONT></DIV></BODY></HTML>" );
   
   // Add the alternate body to the message.
   AlternateView^ alternate = AlternateView::CreateAlternateViewFromString(body);
   message->AlternateViews->Add(alternate);

   // Send the message.
   SmtpClient^ client = gcnew SmtpClient( server );
   client->Credentials = CredentialCache::DefaultNetworkCredentials;
   client->Send( message );
   
   // Display the values in the ContentType for the attachment.
   ContentType^ c = alternate->ContentType;
   Console::WriteLine( L"Content type" );
   Console::WriteLine( c );
   Console::WriteLine( L"Boundary {0}", c->Boundary );
   Console::WriteLine( L"CharSet {0}", c->CharSet );
   Console::WriteLine( L"MediaType {0}", c->MediaType );
   Console::WriteLine( L"Name {0}", c->Name );
   Console::WriteLine( L"Parameters: {0}", c->Parameters->Count );
   IEnumerator^ myEnum = c->Parameters->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      DictionaryEntry^ d = safe_cast<DictionaryEntry^>(myEnum->Current);
      Console::WriteLine( L"{0} = {1}", d->Key, d->Value );
   }

   Console::WriteLine();
   alternate->~AlternateView();
}

public static void CreateMessageWithMultipleViews(string server, string recipients)
{
    // Create a message and set up the recipients.
    MailMessage message = new MailMessage(
        "jane@contoso.com",
        recipients,
        "This email message has multiple views.",
        "This is some plain text.");

    // Construct the alternate body as HTML.
    string body = "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN\">";
    body += "<HTML><HEAD><META http-equiv=Content-Type content=\"text/html; charset=iso-8859-1\">";
    body += "</HEAD><BODY><DIV><FONT face=Arial color=#ff0000 size=2>this is some HTML text";
    body += "</FONT></DIV></BODY></HTML>";

    ContentType mimeType = new System.Net.Mime.ContentType("text/html");
    // Add the alternate body to the message.

    AlternateView alternate = AlternateView.CreateAlternateViewFromString(body, mimeType);
    message.AlternateViews.Add(alternate);

    // Send the message.
    SmtpClient client = new SmtpClient(server);
    client.Credentials = CredentialCache.DefaultNetworkCredentials;

    try
    {
        client.Send(message);
    }
    catch (Exception ex)
    {
        Console.WriteLine("Exception caught in CreateMessageWithMultipleViews(): {0}",
            ex.ToString());
    }
    // Display the values in the ContentType for the attachment.
    ContentType c = alternate.ContentType;
    Console.WriteLine("Content type");
    Console.WriteLine(c.ToString());
    Console.WriteLine("Boundary {0}", c.Boundary);
    Console.WriteLine("CharSet {0}", c.CharSet);
    Console.WriteLine("MediaType {0}", c.MediaType);
    Console.WriteLine("Name {0}", c.Name);
    Console.WriteLine("Parameters: {0}", c.Parameters.Count);
    foreach (DictionaryEntry d in c.Parameters)
    {
        Console.WriteLine("{0} = {1}", d.Key, d.Value);
    }
    Console.WriteLine();
    alternate.Dispose();
}

Remarks

In the following example of a Content-Type header, the value of the Boundary parameter is "-----boundary---0".

content-type: multipart/mixed; boundary=-----boundary---0

Set this property to null or String.Empty to remove the boundary information from the header.

The syntax of the Content-Type header is described in RFC 2045 Section 5.1. An in-depth discussion of the boundary parameter is contained in RFC 2046 Section 5.1.1. These RFCs are available at https://www.ietf.org.

Applies to

Product	Versions
.NET	Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

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