This topic provides technical details on embedding license information into your applications. This is a special resource that must be present in every application that uses dotConnect for PostgreSQL.

The article consists of following sections:

• General Information
• Licensing .NET Standard (.NET Core) Projects
• Adding License Automatically
• Adding License Manually
• Class Libraries Support
• Licensing ASP.NET Applications
• Licensing Compact Framework Projects
• DbProviderFactory Notes
• Compiling License Manually
• Licensing Mono Projects
• Troubleshooting

General Information

dotConnect for PostgreSQL uses .NET component licensing. To build an application dotConnect for PostgreSQL requires valid license. If no license is available, dotConnect for PostgreSQL does not work.

License information is a specially formed embedded resource. Usually you do not have to care about embedding license in your application. When you install dotConnect for PostgreSQL, the system is configured so that licensing is done transparently. End-users of your software do not require any additional license.

dotConnect for PostgreSQL includes License Wizard that helps you configure license information. The wizard analyzes the current project, informs you about problems found, and performs some actions needed to fix the problems.

To invoke the wizard choose PostgreSQL | License Information from the Visual Studio Tools menu. Then click the Fix buttons in the dialog and follow the wizard's instructions. In most cases this is enough to configure .NET component licensing.

The following table helps get started quickly with dotConnect for PostgreSQL licensing. Find your type of application and follow links to corresponding sections of the article.

Diagram	Explanation
	This is general case of licensed .NET Framework application. Whatever the type of application you develop, read carefully sections Adding License Automatically and Adding License Manually.
	These two diagrams show how you can use dotConnect for PostgreSQL through a class library. In addition to Adding License Automatically and Adding License Manually please read section Class Libraries Support.
	These are two modes of accessing dotConnect for PostgreSQL within ASP.NET application. In addition to Adding License Automatically and Adding License Manually please read section Licensing ASP.NET Applications.
	Some applications that have no licensing information embedded, and use DbProviderFactory to operate dotConnect for PostgreSQL, require the product installed on the computer. Refer to section DbProviderFactory Notes for more information.

Licensing .NET Standard (.NET Core) Projects

.NET Standard compatible assemblies of the dotConnect for PostgreSQL use a different licensing mechanism. For .NET Standard (.NET Core) projects you must add the license key either as a connection string parameter or as a file to the C:\ProgramData\Devart\dotConnect\License\ folder. For more information read the Licensing .NET Standard (.NET Core) Projects topic.

Adding License Automatically

License is automatically added to project when you drop a PgSqlConnection component from Toolbox onto a form designer.

Under .NET Compact Framework, in the moment of compilation license information is automatically added if the dotConnect for PostgreSQL addin for Visual Studio is running.

Adding License Manually

In some cases you have to manually add license. It is necessary for console applications, class libraries, and existing projects initially built with dotConnect for PostgreSQL version that did not use component licensing, that is, 2.40 and older. In this case perform the following steps:

• Create a file named licenses.licx, if this file does not exist yet.
• Open the file with a text editor and place this line inside:
  Devart.Data.PostgreSql.PgSqlConnection, Devart.Data.PostgreSql
• Save the file and add it to your project.
• Make sure it is embedded as a resource.

If IDE fails to compile the license automatically, you can do it yourself as described in section Compiling License Manually.

Class Libraries Support

In case where it is impossible to put the license information straight to executable file, dotConnect for PostgreSQL allows you to create class libraries that can be used with certain executable files. To do this perform the following steps:

1. Create and setup file named licenses.licx as described above.
2. Create a text file named licenses.config and place it next to licenses.licx.
3. In this file enumerate names of executable files that will work with the library, every file name on separate line, for example:
   
   MyApplication.exe
   MyAnotherApp.exe
   ExtraTool.exe

You do not have to add the file licenses.config to project.

Licensing a library without specifying the executables that will use it is possible by agreement with Devart. For details on this, please mail to [email protected] or [email protected].

Licensing Web Projects

There are two types of web projects depending on the type of licensing.

1. First, Web Application Project (Web Forms, MVC, Web API, etc.) are compiled entirely, so that web server does not perform any compilation on demand. In this case licensing web applications is same as licensing common Class Library applications.
2. Second, there are Web Site Projects, when source files are uploaded to server, where they are compiled on user request. In this case you should deploy a special assembly App_Licenses.dll to the Bin directory of your site for the Web Site projects. To create this assembly, right-click the licenses.licx file in the Solution Explorer view and then click Build Runtime Licenses. The required assembly will be created automatically. Note that the corresponding shortcut menu command is available when the licenses.licx file is located in the root folder of the site.

Licensing Compact Framework Projects

For .NET Compact Framework the Visual Studio add-in automatically embeds all required information into every assembly that uses Devart.Data.PostgreSql.dll library. Class libraries are supported automatically.

If the license fails to be added to a project, you can add and compile it manually. Note that there is no license compiler from Microsoft for .NET Compact Framework. You can request the compiler from Devart support team.

There is a known problem with the .NET Compact Framework. A "License not found" exception can be thrown by PgSqlDataAdapter.Fill method in case when PgSqlConnection had never been opened. To avoid the problem just open (or open and close) any connection before calling the PgSqlDataAdapter.Fill method.

DbProviderFactory Notes

Applications that call dotConnect for PostgreSQL through DbProviderFactory require registration in DbProviderFactory. This registration can be performed either by launching installer of dotConnect for PostgreSQL with the Minimal install type (the licenses.licx file is not required in this case), or manually as it is described in the Deployment topic. DbProviderFactory support allows using dotConnect for PostgreSQL in SQL Server 2008/2012 Business Intelligence Solutions.

Compiling License Manually

The license resource cannot be compiled automatically when your project does not have reference to Devart.Data.PostgreSql.dll or dotConnect for PostgreSQL is not installed on your build server. This section describes how to compile the required resource manually.

Generate licensing resource file using following command line:
"%Compiler Path%\lc.exe" /target:MyApplication.exe /complist:licenses.licx /i:"%Assembly Path%\Devart.Data.PostgreSql.dll"
Where

• %Compiler Path% is a path to appropriate lc.exe file (for example, C:\Program Files\Microsoft.NET\SDK\v2.0\Bin);
• MyApplication.exe is name of your target executable file;
• licenses.licx is a text file described earlier in this topic;
• %Assembly Path% is location of Devart.Data.PostgreSql.dll assembly

License compiler will generate 'MyApplication.exe.licenses' resource file. You should add this file to your project as an embedded resource. Note that you should not add licenses.licx to the project because the *.licenses file already includes all the necessary license information.

If the default namespace of your project is not an empty string, it must be the same as the target assembly name (in this case - 'MyApplication'). IDE adds the default namespace to the resource name when building application, so you have to rename 'MyApplication.exe.licenses' to 'exe.licenses' before adding it to project. If the default namespace of your project is not set (is an empty string) you do not have to rename the resource file before adding it to project.

You can also generate the license resource manually for the class library assembly (*.dll) in the same way. Just place licenses.config in the folder with your licenses.licx (and change /target:MyApplication.exe to /target:YourClassLibraryName.dll).

Licensing Mono Projects

Since automatic license generation and embedding is not possible with Mono you have to add and compile license manually as described above.

Troubleshooting

When something's wrong with license information you get one of the following exceptions on connecting to server: