X509Certificate Constructor (String)


Initializes a new instance of the X509Certificate class using the name of a PKCS7 signed file.

Namespace:   System.Security.Cryptography.X509Certificates
Assembly:  mscorlib (in mscorlib.dll)

public X509Certificate(
	string fileName


Type: System.String

The name of a PKCS7 signed file.

Exception Condition

An error with the certificate occurs. For example:

  • The certificate file does not exist.

  • The certificate is invalid.

  • The certificate's password is incorrect.


The fileName parameter is null.

ASN.1 DER is the only certificate format supported by this class.

If you create an X509Certificate certificate by specifying a PKCS7 signed file store for fileName, the X509Certificate is created for the certificate that signed the store rather than for any of the certificates within the store.

The following example loads an X.509 certificate from a file, calls the ToString method, and displays the results to the console.

using System;
using System.Security.Cryptography.X509Certificates;

public class X509

    public static void Main()

        // The path to the certificate.
        string Certificate = "Certificate.cer";

        // Load the certificate into an X509Certificate object.
        X509Certificate cert = new X509Certificate(Certificate);

        // Get the value.
        string resultsTrue = cert.ToString(true);

        // Display the value to the console.

        // Get the value.
        string resultsFalse = cert.ToString(false);

        // Display the value to the console.




for permission to read the file described by the fileName parameter. Security action: Demand. Associated enumeration: EnvironmentPermissionAccess.Read


for permission to create a key container. Security action: Demand. Associated enumeration: KeyContainerPermissionFlags.Create

.NET Framework
Available since 2.0
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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