Additional information: The ADO provider with the fixed name "Npgsql" is not registered in the computer or application configuration file or cannot be loaded. For more information, see inner exception

Additional information: The ADO provider with the fixed name "Npgsql" is not registered in the computer or application configuration file or cannot be loaded. For more information, see inner exception

Workaround

Add the following to the configuration of App. Config: The red-bottom part is the version number of the npgsql you call

<system.data>    <DbProviderFactories>      <remove invariant= "Npgsql"/>      <add name= " Npgsql data Provider "           invariant=" Npgsql "           description=". Net data Provider for PostgreSQL "           type=" Npgsql.npgsqlfactory, Npgsql, version=2.2.0.0, culture=neutral, Publickeytoken=5d8b90d52f46fda7 "           support= "FF"/>    </DbProviderFactories>  </system.data>