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LicFileLicenseProvider Class

.NET Framework 4

Provides an implementation of a LicenseProvider. The provider works in a similar fashion to the Microsoft .NET Framework standard licensing model.

System.Object
  System.ComponentModel.LicenseProvider
    System.ComponentModel.LicFileLicenseProvider

Namespace:  System.ComponentModel
Assembly:  System (in System.dll)
C#
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[HostProtectionAttribute(SecurityAction.LinkDemand, SharedState = true)]
public class LicFileLicenseProvider : LicenseProvider

The LicFileLicenseProvider type exposes the following members.

  Name Description
Public method LicFileLicenseProvider Initializes a new instance of the LicFileLicenseProvider class.
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  Name Description
Public method Equals(Object) Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected method Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method GetHashCode Serves as a hash function for a particular type. (Inherited from Object.)
Protected method GetKey Returns a key for the specified type.
Public method GetLicense Returns a license for the instance of the component, if one is available. (Overrides LicenseProvider.GetLicense(LicenseContext, Type, Object, Boolean).)
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Protected method IsKeyValid Determines whether the key that the GetLicense method retrieves is valid for the specified type.
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method ToString Returns a string that represents the current object. (Inherited from Object.)
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The LicFileLicenseProvider offers GetLicense and IsKeyValid methods. The IsKeyValid method determines whether the LicenseKey retrieved by the GetLicense method is valid. When you inherit from this class, you can override the IsKeyValid method to provide your own validation logic.

This class exists to provide similar licensing functionality to COM licensing and uses text license files.

For more information on licensing, see How to: License Components and Controls.

Note Note

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

The following example creates a licensed control using the Validate method. It uses LicFileLicenseProvider for the license manager.

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using System;
using System.ComponentModel;
using System.Windows.Forms;


// Adds the LicenseProviderAttribute to the control.
[LicenseProvider(typeof(LicFileLicenseProvider))]
public class MyControl : Control 
{

   // Creates a new, null license.
   private License license = null;

   public MyControl () 
   {

      // Adds Validate to the control's constructor.
      license = LicenseManager.Validate(typeof(MyControl), this);

      // Insert code to perform other instance creation tasks here.
   }

   protected override void Dispose(bool disposing) 
   {
      if(disposing)
      {
         if (license != null) 
         {
            license.Dispose();
            license = null;
         }
      }
   }

}

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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additonal code for understanding and to complement the example above

the example is excellent. Be sure to check out the resources on "How to: License Components and Controls"
and create the necessary .lic files in the executable directory when installed
Of course it's up one's imagination to embed additional info encrypted in the .lic or someplace in the  pc to check for validity of the users' licenses from the overriden GetLicence.

Here is a simplistic sample that will work despite far from a good one.

[LicenseProvider(typeof(LicFileLicenseProvider))]
 class Lic : LicFileLicenseProvider
 {
  private License license = null;
  public override sealed License GetLicense(LicenseContext context, Type type, Object instance,
   bool allowExceptions)
  {
     // optional usagemode check: if (context.UsageMode == LicenseUsageMode.Runtime)
     //   {
          // do you own checking here for additional info
        LicenseContext lc = new LicenseContext();
        lc.SetSavedLicenseKey(type, __Data1);  // __Data1 is whatever your own of scheme
        return (License)LicenseManager.CreateWithContext(type, lc);
     // optional: } else
     //    optional processing for other mode  { .... }
   }
 }

Furthermore, if one were to spend time to code the license scheme, one might as well make it harder to reverse engineer by obfuscation of his code for release.


I was in a bad hurry,tired state and missed the resources section; wasted time looking to how to make the example code work.

I hope the information presented may help others

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