Troubleshoot the Get started with Windows Communication Foundation tutorials

Article
08/16/2022

This article provides solutions for the most common problems and errors you might face when you follow the steps in the Tutorial: Get started with Windows Communication Foundation applications.

Common problems

I can't find the project files on my hard drive.

Visual Studio saves project files in C:\Users\<user name>\source\repos.

I can't find the App.config file generated by Svcutil.exe.

In Visual Studio, the Add Existing Item window only displays files with the following extensions by default:

.cs
.resx
.settings
.xsd
.wsdl

To display all file types, select All Files (*.*) in the drop-down list in the lower-right corner of the Add Existing Item window.

Common errors

Compile the service application

Error BC30420 'Sub Main' was not found in 'GettingStartedHost.Module1'.

The entry point is incorrect for the Visual Basic application. Make the following change:

In the Solution Explorer window, select the GettingStartedHost folder, and then select Properties from the shortcut menu. a. In the GettingStartedHost window, for Startup object, select Service.Program (or the entry point for your particular application) from the list. b. From the main menu, select File > Save All.

Run the service application

HTTP could not register URL 'http://+:8000/GettingStarted/CalculatorService'. Your process does not have access rights to this namespace.

For proper access, start the process hosting the Windows Communication Foundation (WCF) service with administrative privileges:

For Visual Studio: Select the Visual Studio program in the Start menu, and then select More > Run as administrator from the shortcut menu.
For a console window: Select Command Prompt in the Start menu, and then select More > Run As administrator from the shortcut menu.
For Windows Explorer: Select the executable, and then select Run as administrator from the shortcut menu.

Compile the client application

'CalculatorClient', does not contain a definition for '<method name>' and no extension method '<method name>' accepting a first argument of type 'CalculatorClient' could be found (are you missing a using directive or an assembly reference?)

Only those methods that you mark with the ServiceOperationAttribute attribute are publicly exposed. If you omit the ServiceOperationAttribute attribute from a method in the ICalculator interface, you receive this error message during compilation.

The type or namespace name 'CalculatorClient' could not be found (are you missing a using directive or an assembly reference?)

You receive this error if you don't add the generatedProxy.cs (or generatedProxy.vb) file to your client project when you generated them with the Svcutil.exe tool.

Run the client application

Unhandled Exception: System.ServiceModel.EndpointNotFoundException: Could not connect to 'http://localhost:8000/GettingStarted/CalculatorService'. TCP error code 10061: No connection could be made because the target machine actively refused it.

This error occurs if you run the client application without first starting the service. First, run the host application to start the service, and then run the client application.

Use the Svcutil.exe tool

'Svcutil' is not recognized as an internal or external command, operable program, or batch file.

Svcutil.exe must be in the system path. The easiest solution is to use the Visual Studio command prompt. From the Start menu, select the Visual Studio <version> directory, then select Developer Command Prompt for VS <version>. This command prompt sets the system path to the correct locations for all tools shipped as part of Visual Studio.

Run the service and client applications

System.ServiceModel.Security.SecurityNegotiationException: SOAP security negotiation with 'http://localhost:8000/GettingStarted/CalculatorService' for target 'http://localhost:8000/GettingStarted/CalculatorService' failed

This error occurs on a domain-joined computer that doesn't have network connectivity. Connect your computer to the network or turn off security for both the service and the client.

To turn off security:

For the service, replace the code that creates the WSHttpBinding with the following code:

// Step 3: Add a service endpoint.
selfhost.AddServiceEndpoint(typeof(ICalculator), new WSHttpBinding(SecurityMode.None), "CalculatorService");

For the client, in the configuration file, update the <security> element under the <binding> element as follows:
```
<binding name="WSHttpBinding_ICalculator">
  <security mode="None" />
</binding>
```

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