Question

All, I have extended this tutorial to get and reverse string displayed in two seperate WinForm applications. However, the end goal is to get this working between to WinForm apps that pass SQL between eachother. To facilitate this I have extended this example and the following is what I have

A library .dll containing

public class WcfInterface
{
    private static WcfInterface instance;
    private ServiceHost host;
    private const string serviceEnd = "Done";

    protected WcfInterface()
    {
    }

    public static WcfInterface Instance()
    {
        if (instance == null)
            instance = new WcfInterface();
        return instance;
    }

    public void OpenServiceHost<T, U>() 
    {
        host = new ServiceHost(typeof(U), new Uri[] { new Uri("net.pipe://localhost") });
        host.AddServiceEndpoint(typeof(T), new NetNamedPipeBinding(), serviceEnd);
        host.Open();
    }

    public void CloseServiceHost<T>()
    {
        host.Close();
    }

    public T AddListnerToServiceHost<T>()
    {
        ChannelFactory<T> pipeFactory = 
            new ChannelFactory<T>(new NetNamedPipeBinding(), 
                                         new EndpointAddress(String.Format("net.pipe://localhost/{0}", 
                                                                                      serviceEnd)));
        T pipeProxy = pipeFactory.CreateChannel();
        return pipeProxy;
    }
}

So on the ‘server’ form, I do

private void Form1_Load(object sender, EventArgs e)
{
    List<string> sqlList = new List<string>();
    foreach (string line in this.richTextBoxSql.Lines)
        sqlList.Add(line);
    SqlInfo sqlInfo = new SqlInfo(sqlList);
    WcfInterface wcfInterface = WcfInterface.Instance();
    wcfInterface.OpenServiceHost<ISqlListing, SqlInfo>();
}

Where

public class SqlInfo : ISqlListing
{
    private List<string> sqlList;
    public SqlInfo(List<string> sqlList)
    {
        this.sqlList = sqlList;
    }

    public List<string> PullSql()
    {
        return sqlList;
    }
}

[ServiceContract]
public interface ISqlListing
{
    [OperationContract]
    List<string> PullSql();
}

In the client WinForm app

private ISqlListing pipeProxy;
public Form1()
{
    InitializeComponent();
    WcfInterface wcfInterface = WcfInterface.Instance();
    pipeProxy = wcfInterface.AddListnerToServiceHost<ISqlListing>();
}

and on the click event I attampt to get the List<string> from the server

private void button1_Click(object sender, EventArgs e)
{
    this.richTextBoxSql.Text = pipeProxy.PullSql().ToString(); // Code hangs here.
}

My question is what is wrong with this?

Thanks for your time.

---

Edit. I have now also changed the client code according to comments as follows

private ISqlListing pipeProxy { get; set; }
private const string serviceEnd = "Done";

public Form1()
{
    InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
    this.richTextBoxSql.Text = pipeProxy.PullSql().ToString(); 
 }

private void Form1_Load(object sender, EventArgs e)
{
    ChannelFactory<ISqlListing> pipeFactory =
    new ChannelFactory<ISqlListing>(
      new NetNamedPipeBinding(),
      new EndpointAddress(
         String.Format("net.pipe://localhost/{0}", serviceEnd)));

    pipeProxy = pipeFactory.CreateChannel();
}

this also hangs on the click event.

Answer 1

The way you have the code set up, you are creating a WCF server on the client by referencing WcfInterface.Instance. You are then calling it from the same thread that it is being served on, causing your application to lock up.

There are a number of ways to get around this. Here are a few that come to mind:

• Get the service running in your first WinForm app, then use the “Add Service Reference” functionality in visual studio to create your proxies. Note that you’ll have to
• You can still reference a common library for the WCF contracts, but rework your code so that you’re not creating an instance of the service in your “client” WinForms app.