http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=13189

MSDN Dokumentation…

Imagine we have a little function like this:

And we call it with some code like this:

string Name = “Jimi Hendrix”;

TryAndChangeTheValue(Name);

MessageBox.Show(Name);

What happens? Does it return ‘Jimi Hendrix’ or ‘Ziggy Stardust’?

It shows ‘Jimi Hendrix’. Because the parameter does not have the ‘ref‘ keyword, a copy of the value [Weiter lesen...]]]> Quelle:
http://www.secretgeek.net/ref_params.asp

Imagine we have a little function like this:

And we call it with some code like this:

What happens? Does it return ‘Jimi Hendrix’ or ‘Ziggy Stardust’?

It shows ‘Jimi Hendrix’. Because the parameter does not have the ‘ref‘ keyword, a copy of the value ‘Name’ is created, altered and then not returned from the stack. So the initial value of ‘Name’ is displayed in the messagebox.

If you want the function to affect the displayed message, you need to use the ref keyword, as follows:

And you need to add the keyword ref to your calling code:

Now when the above code is run, the value ‘Ziggy Stardust’ will be displayed.

Okay, recap over. Time to think about classes.

But what happens when you do (or don’t) use the ref keyword on an object parameter?

Imagine we have a simple little class like this:

It has one public field, ‘Value’ which defaults to ‘Jimi Hendrix’.

And now imagine we have a function that looks like this:

It accepts a ‘NameClass‘ object, and changes the name property to ‘Ziggy Stardust’.

Now what happens when we call the method, and then check the value…

Will the messagebox show ‘Jimi Hendrix’ or ‘Ziggy Stardust’?

Before you answer, consider this case:

What if we changed the function to look like this:

So that now the parameter is of type reference. (We’ll also need to add the ‘ref‘ keyword to our calling code)

Will the ‘ref‘ keyword make any difference to our test? If so, why? If not, why not?

For both these tests, the result will be ‘Ziggy Stardust’. The ref keyword won’t make a difference to the results.

Does that mean that the ref keyword was ignored? Not at all.

The important thing is that the ref keyword applies to the parameter (name), not to its properties (name.Value).

So let’s look at a case where the function doesn’t just change a property of the parameters, but tries to change the parameter itself. In that cases the ref parameter will make an important difference.

Here’s an example where our function gets sloppy and drops the object.

What will happen now?

Will this code:

Still return ‘Ziggy Stardust?’ Or will we get a null reference exception?

We will still get ‘Ziggy Stardust’ out. There won’t be a null reference exception, because the thing that was set to null was a value copy of the object reference, not a direct reference to the object.

The object itself wasn’t affected by the ‘name = null’ line. That merely stopped a value on the stack from pointing to the object.

And then consider the same code, but with the ‘ref‘ keyword:

What will happen when this code is used to call it?

Will we get a ‘ziggy stardust’? Or a null reference exception?

In this case we get a null reference exception. Because now when the name = null line was executed, it was the reference itself that was set to null, not just a copy of it on the stack.

Okay that’s all i want to say about that.

Folgender Code serialisiert und deserialisiert ein Objekt mit dem XmlSerializer. Damit der serialisierte String (XML) auch über Webservices problemlos transferiert werden kann, wird [Weiter lesen...]]]> Ein Objekt kann in XML serialisiert werden. Auf die Rahmenbedingung, was serialisiert werden kann und was nicht, gehe ich jetzt mal nicht ein. (Hoffentlich kann ich das mal aufarbeiten und auch posten.)

Folgender Code serialisiert und deserialisiert ein Objekt mit dem XmlSerializer. Damit der serialisierte String (XML) auch über Webservices problemlos transferiert werden kann, wird der String zu Base64 codiert.

Forumsbeitrag

#region Serialisierung ReportPublication[] serializeObject = publications.ToArray();

// Serialisierung
MemoryStream serializeMStream = new MemoryStream();
XmlTextWriter xmlWriter = new XmlTextWriter(serializeMStream, Encoding.UTF8);
XmlSerializer serializer = new XmlSerializer(typeof(ReportPublication[]));
serializer.Serialize(xmlWriter, serializeObject);

// String erzeugen und Base64 codieren
serializeMStream.Seek(0, 0);
string theString = Convert.ToBase64String(serializeMStream.GetBuffer(), 0, (int)serializeMStream.Length);

#endregion

#region Deserialisierung

MemoryStream deserializeMStream = new MemoryStream();
ReportPublication[] deserializedObject = null;

// Base64 Decodierung
byte[] byteArray = Convert.FromBase64String(theString);
deserializeMStream = new MemoryStream(byteArray);
deserializeMStream.Seek(0, 0);

// Deserialisierung
XmlTextReader xmlReader = new XmlTextReader(deserializeMStream);
XmlSerializer deserializer = new XmlSerializer(typeof(ReportPublication[]));
deserializedObject = (ReportPublication[])deserializer.Deserialize(xmlReader);
xmlReader.Close();

#endregion

Hier noch zur Archivierung: Artikel:XML-Serialisieren Grundtechnik

Die MSDN Seite dazu …

Und alle Formatierungsmöglichkeiten hier:

http://www.yoda.arachsys.com/csharp/constructors.html

http://www.andymcm.com/csharpfaq.htm#3.9

Schöne Übersicht über die [Weiter lesen...]]]> string myName = "Fred"; String.Format("Name = {0}, hours = {1:hh}", myName, DateTime.Now);

The fixed text is “Name = ” and “, hours = “. The format items are “{0}”, whose index is 0, which corresponds to the object myName, and “{1:hh}”, whose index is 1, which corresponds to the object DateTime.Now.

Schöne Übersicht über die Formatmöglichkeiten:

http://alexonasp.net/samples/stringformatting/Default.aspx

http://msdn.microsoft.com/de-de/library/7x5bacwt(VS.80).aspx