Getting “Object is read only” error when setting C

问题:

I have a proxy object generated by Visual Studio (client side) named ServerClient. I am attempting to set ClientCredentials.UserName.UserName/Password before opening up a new connection using this code:

InstanceContext context = new InstanceContext(this);

m_client = new ServerClient(context);
m_client.ClientCredentials.UserName.UserName = "Sample";

As soon as the code hits the UserName line it fails with an "Object is read-only" error. I know this can happen if the connection is already open or faulted, but at this point I haven't called context.Open() yet.

I have configured the Bindings (which uses netTcpBinding) to use Message as it's security mode, and MessageClientCredentialType is set to UserName.

Any ideas?

回答1:

I noticed that after creating an instance of the proxy class for the service, I can set the Username and Password once without errors and do a successful call to my webservice. When I then try to set the Username and Password again on the existing instance (unnecessary of course) I get the 'Object is Read-Only' error you mentioned. Setting the values once per instance lifetime worked for me.

回答2:

It appears that you can only access these properties pretty early in the instanciation cycle. If I override the constructor in the proxy class (ServerClient), I'm able to set these properties:

base.ClientCredentials.UserName.UserName = "Sample";

I'm beginning to appreciate the people who suggest not using the automatically built proxies provided by VS.

回答3:

here is the solution:

using SysSvcmod = System.ServiceModel.Description;

SysSvcmod.ClientCredentials clientCredentials = new SysSvcmod.ClientCredentials();
clientCredentials.UserName.UserName = "user_name";
clientCredentials.UserName.Password = "pass_word";

m_client.ChannelFactory.Endpoint.Behaviors.RemoveAt(1);
m_client.ChannelFactory.Endpoint.Behaviors.Add(clientCredentials);

回答4:

I have similar code that's passing UserName fine:

  FooServiceClient client = new FooServiceClient("BasicHttpBinding_IFooService");
  client.ClientCredentials.UserName.UserName = "user";
  client.ClientCredentials.UserName.Password = "password";

Try creating the proxy with binding name in app.config.

回答5:

I was facing same problem, my code started working when I changed my code i.e. assigning values to Client credential immediately after initializing Client object.

here is the solution ,

ProductClient Manager = new  ProductClient();    
Manager.ClientCredentials.UserName.UserName = txtUserName.Text;
Manager.ClientCredentials.UserName.Password = txtPassword.Text;

回答6:

This will not happen if the service reference is added through -> Add service reference ->Advanced->Add Web Reference-> Url/wsdl (local disk file).

回答7:

I was facing this issue where I was trying to create a generic method to create a clients for different end points.

Here how I achieved this.

    public static T CreateClient<T>(string url) where T : class
    {
        EndpointAddress endPoint = new EndpointAddress(url);
        CustomBinding binding = CreateCustomBinding();

        T client = (T)Activator.CreateInstance(typeof(T), new object[] { binding, endPoint });
        SetClientCredentials(client);

        return client;
    }

    public static void SetClientCredentials(dynamic obj)
    {
        obj.ChannelFactory.Endpoint.Behaviors.Remove<ClientCredentials>();
        obj.ChannelFactory.Endpoint.Behaviors.Add(new CustomCredentials());

        obj.ClientCredentials.UserName.UserName = "UserId";
        obj.ClientCredentials.UserName.Password = "Password";
    }

回答8:

The correct syntax is:

// Remove the ClientCredentials behavior.
client.ChannelFactory.Endpoint.Behaviors.Remove<ClientCredentials>();

// Add a custom client credentials instance to the behaviors collection.
client.ChannelFactory.Endpoint.Behaviors.Add(new MyClientCredentials());

http://msdn.microsoft.com/en-us/library/ms730868.aspx

It worked for me.

回答9:

I think your problem might be related to the use of the InstanceContext. I thought that was only needed for duplex communication channels from the server side.

I admit I'm not sure about this, but I think in this case you are telling the client to use an existing instance context so it thinks there is already a running service and will not allow changes.

What is driving the use of InstanceContext?

回答10:

If using a duplex client, when you instantiate it the DuplexChannelFactory within the DuplexClientBase that your client is derived from is initialized with existing credentials so it can open the callback channel, which is why the credentials would be read only.

I second Mike's question and also ask why are you using NetTcpBinding if you are not going to use its inherent transport level security? Perhaps an HTTP based binding would be a better fit? That would allow you to use certificate based security which I believe can be modified after instantiation (http://msdn.microsoft.com/en-us/library/ms576164.aspx).

回答11:

A shot in the dark but does netTcpBinding allow username and password validation? Try using application layer (SOAP) security using a http binding

回答12:

or you could just simply check the Credentials

    if (client.ClientCredentials.ClientCertificate.Certificate == null || string.IsNullOrEmpty(client.ClientCredentials.ClientCertificate.Certificate.Thumbprint))
    {
        client.ClientCredentials.ClientCertificate.SetCertificate(
            StoreLocation.LocalMachine,
            StoreName.My,
            X509FindType.FindByThumbprint, ConfigurationManager.AppSettings.Get("CertificateThumbprint"));
    }