Exporting an ADO.NET Database Connection

You can export an ADO.NET connection from a PowerBuilder WPF application, enabling the same database connection to be shared by an external .NET assembly.

Follow these guidelines to export a shared connection:

In your PowerBuilder Transaction object, include a DBMS property that starts with ADO, and a DBParm property that specifies the driver's namespace.
Start the connection before invoking GetAdoConnection.
Use the GetAdoConnection method to export the connection proxy, using this syntax: object GetAdoConnection().

The object is the IAdoConnectionProxy instance to be returned.

The method returns null if it fails to make the connection.
To use the shared connection, your third-party assembly must reference the exported connection proxy and manage the transaction. You can subscribe the IAdoConnection.TransactionChanged event to be notified when the active transaction is changed.
Remember to close the connection.

The proxy's Connection property passes the shareable connection as a System.Data.IDbConnection object, which is available to the third-party .NET assembly at runtime. The active transaction object is assigned to the proxy's IAdoConnectionProxy.Transaction property.

Sample PowerScript code: –

SQLCA.DBMS = "ADO.NET"
SQLCA.AutoCommit = false
SQLCA.DBParm = "Namespace='System.Data.Odbc', DataSource='SQL Anywhere 11 Demo'"
Connect Using SQLCA;
emp.ConnectionProxy = SQLCA.GetAdoConnection()

// db operations
disconnect using SQLCA;

Sample C# assembly code –

// Manage the transaction
public class Emp {
	...

	IAdoConnectionProxy proxy;
	IDbTransaction trans;

	...

	public object ConnectionProxy {
		get { return proxy; }
		set { 
			proxy = value as IAdoConnectionProxy; 
			...
			proxy.TransactionChanged += new EventHandler(proxy_TransactionChanged);
		}
	}

	void proxy_TransactionChanged(object sender, EventArgs e) {
		...
		trans = sender as IDbTransaction;
		...
	}
	...
}