X509BasicConstraintsExtension Class
Defines the constraints set on a certificate. This class cannot be inherited.
Assembly: System (in System.dll)
System.Security.Cryptography.AsnEncodedData
System.Security.Cryptography.X509Certificates.X509Extension
System.Security.Cryptography.X509Certificates.X509BasicConstraintsExtension
| Name | Description | |
|---|---|---|
![]() | X509BasicConstraintsExtension() | Initializes a new instance of the X509BasicConstraintsExtension class. |
![]() | X509BasicConstraintsExtension(AsnEncodedData, Boolean) | Initializes a new instance of the X509BasicConstraintsExtension class using an AsnEncodedData object and a value that identifies whether the extension is critical. |
![]() | X509BasicConstraintsExtension(Boolean, Boolean, Int32, Boolean) | Initializes a new instance of the X509BasicConstraintsExtension class. Parameters specify a value that indicates whether a certificate is a certificate authority (CA) certificate, a value that indicates whether the certificate has a restriction on the number of path levels it allows, the number of levels allowed in a certificate's path, and a value that indicates whether the extension is critical. |
| Name | Description | |
|---|---|---|
![]() | CertificateAuthority | Gets a value indicating whether a certificate is a certificate authority (CA) certificate. |
![]() | Critical | Gets a Boolean value indicating whether the extension is critical.(Inherited from X509Extension.) |
![]() | HasPathLengthConstraint | Gets a value indicating whether a certificate has a restriction on the number of path levels it allows. |
![]() | Oid | Gets or sets the Oid value for an AsnEncodedData object.(Inherited from AsnEncodedData.) |
![]() | PathLengthConstraint | Gets the number of levels allowed in a certificate's path. |
![]() | RawData | Gets or sets the Abstract Syntax Notation One (ASN.1)-encoded data represented in a byte array.(Inherited from AsnEncodedData.) |
| Name | Description | |
|---|---|---|
![]() | CopyFrom(AsnEncodedData) | Initializes a new instance of the X509BasicConstraintsExtension class using an AsnEncodedData object.(Overrides X509Extension.CopyFrom(AsnEncodedData).) |
![]() | Equals(Object) | Determines whether the specified object is equal to the current object.(Inherited from Object.) |
![]() | Format(Boolean) | Returns a formatted version of the Abstract Syntax Notation One (ASN.1)-encoded data as a string.(Inherited from AsnEncodedData.) |
![]() | GetHashCode() | Serves as the default hash function. (Inherited from Object.) |
![]() | GetType() | |
![]() | ToString() | Returns a string that represents the current object.(Inherited from Object.) |
This class provides properties that define the basic constraints set on a certificate.
The following code example demonstrates how to open a user’s personal certificate store and display information about each certificate in the store. This example uses the X509BasicConstraintsExtension class to display the information.
Imports System Imports System.Security.Cryptography Imports System.Security.Cryptography.X509Certificates Module CertSelect Sub Main() Try Dim store As New X509Store("MY", StoreLocation.CurrentUser) store.Open(OpenFlags.ReadOnly Or OpenFlags.OpenExistingOnly) Dim collection As X509Certificate2Collection = CType(store.Certificates, X509Certificate2Collection) Dim i As Integer For i = 0 To collection.Count Dim extension As X509Extension For Each extension In collection(i).Extensions Console.WriteLine(extension.Oid.FriendlyName + "(" + extension.Oid.Value + ")") If extension.Oid.FriendlyName = "Key Usage" Then Dim ext As X509KeyUsageExtension = CType(extension, X509KeyUsageExtension) Console.WriteLine(ext.KeyUsages) End If If extension.Oid.FriendlyName = "Basic Constraints" Then Dim ext As X509BasicConstraintsExtension = CType(extension, X509BasicConstraintsExtension) Console.WriteLine(ext.CertificateAuthority) Console.WriteLine(ext.HasPathLengthConstraint) Console.WriteLine(ext.PathLengthConstraint) End If If extension.Oid.FriendlyName = "Subject Key Identifier" Then Dim ext As X509SubjectKeyIdentifierExtension = CType(extension, X509SubjectKeyIdentifierExtension) Console.WriteLine(ext.SubjectKeyIdentifier) End If If extension.Oid.FriendlyName = "Enhanced Key Usage" Then Dim ext As X509EnhancedKeyUsageExtension = CType(extension, X509EnhancedKeyUsageExtension) Dim oids As OidCollection = ext.EnhancedKeyUsages Dim oid As Oid For Each oid In oids Console.WriteLine(oid.FriendlyName + "(" + oid.Value + ")") Next oid End If Next extension Next i store.Close() Catch Console.WriteLine("Information could not be written out for this certificate.") End Try End Sub End Module
Available since 2.0
Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

