Getting error- Hard-coded logon parameters not allowed when using a Destination Configuration while connecting to SAP server dynamically

The "Hard-coded logon parameters not allowed when using a Destination Configuration" error occurs when you attempt to pass connection parameters directly to the SAP RFC destination while also using a custom destination configuration. This conflict arises because SAP.NET Connector expects either hard-coded parameters or a destination configuration, but not both simultaneously.

Solution

The solution is to implement the IDestinationConfiguration interface and register it with the RfcDestinationManager. This approach centralizes connection parameters and eliminates the conflict with hard-coded values.

Complete Working Example

Below is a complete implementation that resolves the error ?

using SAP.Middleware.Connector;
using System;

public class Program 
{
    static void Main(string[] args) 
    {
        SapConnection con = new SapConnection();
        RfcDestinationManager.RegisterDestinationConfiguration(con);
        RfcDestination dest = RfcDestinationManager.GetDestination("NSP");
        RfcRepository repo = dest.Repository;

        IRfcFunction fReadTable = repo.CreateFunction("ZSOMA");
        fReadTable.SetValue("I_NRO1", 1);
        fReadTable.SetValue("I_NRO2", 2);
        fReadTable.Invoke(dest);
        
        var result = fReadTable.GetValue("E_RESULT");
        Console.WriteLine(result.ToString());
        Console.ReadLine();
    }
}

public class SapConnection : IDestinationConfiguration 
{
    public RfcConfigParameters GetParameters(string destinationName) 
    {
        RfcConfigParameters conf = new RfcConfigParameters();
        if (destinationName == "NSP") 
        {
            conf.Add(RfcConfigParameters.AppServerHost, "sap-vm");
            conf.Add(RfcConfigParameters.SystemNumber, "00");
            conf.Add(RfcConfigParameters.SystemID, "xxx");
            conf.Add(RfcConfigParameters.User, "yourusername");
            conf.Add(RfcConfigParameters.Password, "yourpassword");
            conf.Add(RfcConfigParameters.Client, "001");
        }
        return conf;
    }
    
    public bool ChangeEventsSupported() 
    {
        return true;
    }
    
    public event RfcDestinationManager.ConfigurationChangeHandler ConfigurationChanged;
}

Key Points

IDestinationConfiguration Implementation: The SapConnection class implements IDestinationConfiguration to provide connection parameters dynamically based on the destination name.

Registration: The configuration must be registered with RfcDestinationManager.RegisterDestinationConfiguration() before creating any destinations.

Parameter Configuration: All connection parameters (host, system number, credentials) are configured within the GetParameters method rather than being hard-coded elsewhere.

Additional Reference

For more detailed information about this error and additional solutions, you can refer to the SAP community discussion: https://archive.sap.com/discussions/thread/3171324

Conclusion

This approach ensures proper separation of connection logic and eliminates the parameter conflict that causes the "Hard-coded logon parameters not allowed" error when connecting to SAP servers dynamically.