Extend your web.config

web.config files can be easily extended using the configSection tags.

A brief overview is given by Aaron Johnson on his blog, referring the original MSDN documentation.

Also another brief summary by Dieder Tierman and a very good How-to on MSDN how to write own section handlers.

You Have Created a Service

Sometimes, simple things end up as epic battles. If you try to MSN Search and Google for the nasty “You have create a Service” page for IIS hosted WCF services, you will and up with a lot of pre-release information and noise in the search results. Actually, you might spend days in finding some relevant information.

Yesterday, I was finally pointed to the right place in the MSDN documentation where you can find this specific information:

<serviceDebug httpHelpPageEnabled="Boolean"
    httpHelpPageUrl="Uri"
    httpsHelpPageEnabled="Boolean"
    httpsHelpPageUrl="Uri"
    includeExceptionDetailInFaults="Boolean" />

With the serviceDebug tag it should be possible to get rid of the page. It is easy to find as long as you know you have to search for the term HTML help page.

XLINQ Summary

I just found this nice LINQ to XML summary on The Code Project.

WCF, .NET 3.5 and HTTP Request Content

The new Web Programming Model of WCF and the .NET Framework brings some very useful features such as the WebGet and the WebInvoke Attribute and the capability to deal directly with HTTP requests. But how do we access the HTTP request in these methods? Dealing with HTTP requests and responses using the System.Net namespace is quite straight forward. Therefore, we have a look in sending and receiving a simple HTTP request:

HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(myUrl);byte[] a_dataBytes = Encoding.UTF8.GetBytes(data);
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = a_dataBytes.Length;

Stream requestStream = request.GetRequestStream();
requestStream.Write(a_dataBytes, 0, a_dataBytes.Length);
WebResponse response = request.GetResponse(); StreamReader responseReader = new StreamReader(response.GetResponseStream(), Encoding.UTF8); var content = responseReader.ReadToEnd();

Now we want to access the HTTP context within a operation with the following signature:

[OperationContract]
[WebInvoke(Method = "PUT", UriTemplate = "{uri}")]
bool Put(string uri);

Accessing the context of the incoming request is straightforward using the WebOperationContext class.

IncomingWebRequestContext context =
WebOperationContext.Current.IncomingRequest;

var length = context.ContentLength;
var type = context.ContentType;
var headers = context.Headers;

Since the documentation does not provide many example code, and the ORCAS samples do not cover this yet, I had to figure out how to access the content of the incoming request. After spending hours on MSN Search, Google and the MSDN Library I finally tried out something. In some general examples, either a Message or a Stream is passed over as single parameter to the operation. Hence, I changed the contract as follows:

[OperationContract]
[WebInvoke(Method = "PUT", UriTemplate = "{uri}")]
bool Put(string uri, Stream stream);

Reading the content then is easy:

var reader = new StreamReader(stream);string content = reader.ReadToEnd();

This solution however comes up with one major drawback: If you try to access your foo.svc via browser you will end up some error telling you “For request in operation Post to be a stream the operation must have a single parameter whose type is Stream.”. Also calling foo.svc?wsdl will end up in some exception in the WSDL export extension.

LINQ to XML

One of the features I was looking for, is the LINQ to XML capability of the .NET Framework 3.5.

Disabled MenuItems in WPF

Maybe this is a bug: Creating a ContextMenu as child of a Canvas, the event handlers CanExecute and Execute have never been executed? This took me almost two hours to figure out why. Basically, I do my command binding like

CommandBinding exitCmd = new CommandBinding(DesignerCommands.Exit);
exitCmd.CanExecute += new CanExecuteRoutedEventHandler(exitCmd_CanExecute);
exitCmd.Executed += new ExecutedRoutedEventHandler(exitCmd_Executed);
CommandBindings.Add(exitCmd);

To me, it looks like there is a minor problem in command binding whilst using command binding this manner in controls which never get the focus (such as a Canvas). Since the handlers are never fired. An easy workaround is to add additional command binding within your XAML code.

<ContextMenu.CommandBindings>
 <CommandBindingCommand="e:MyCommands.Exit" CanExecute="exitCmd_CanExecute" Executed="exitCmd_Executed"/>
</ContextMenu.CommandBindings>

I checked a couple of web sites and found one site, where the problem is described a bit more in detail. Also Aaron describes a second work around that requires some lines of code.

WPF Data Binding

Best points to start understanding WPF data binding are the MSDN articles “Windows Presentation Foundation Data Binding” here and here. More can be found in the MSDN magazine article Customizing Controls For Windows Presentation Foundation. To learn how to bind to element properties the forum entry may help. A somewhat twisted introduction to Styles and Templates can be found here.