The community is working on translating this tutorial into Danish, but it seems that no one has started the translation process for this article yet. If you can help us, then please click "More info".
If you are fluent in Danish, then please help us - just point to any untranslated element (highlighted with a yellow left border - remember that images should have their titles translated as well!) inside the article and click the translation button to get started. Or have a look at the current translation status for the Danish language.
If you see a translation that you think looks wrong, then please consult the original article to make sure and then use the vote button to let us know about it.
Please help us by translating the following metadata for the article/chapter, if they are not already translated.
If you are not satisfied with the translation of a specific metadata item, you may vote it down - when it reaches a certain negative threshold, it will be removed. Please only submit an altered translation of a metadata item if you have good reasons to do so!
ASP.NET is an event-driven way of making web applications. With PHP and Classic ASP, you have one file, which is executed line after line, from start to end. However, ASP.NET is very different. Here we have events, which are either activated by the user in one way or another. In the previous example, we used the Page_Load method. Actually, this is an event, which the Page class calls when the page is loaded. We will use the same technique in the next example, where we will add a couple of controls to our simple hello world example. To make it a bit more interesting, we will change the "world" word with something defined by the user. Have a look at this codelisting, where we add two new controls: A Button control and a TextBox control.
<form id="form1" runat="server"> <div> <asp:Label runat="server" id="HelloWorldLabel"></asp:Label> <br /><br /> <asp:TextBox runat="server" id="TextInput" /> <asp:Button runat="server" id="GreetButton" text="Say Hello!" /> </div> </form>
As you can see, we now have the 2 new controls added, but they really can't do much at the moment. You can run the example if you wish to check this out for your self - if you click the button, the page is simply reloaded. Let's change that, and let's start by doing it the easy way. VS comes with a WYSIWYG editor, and while I hardly ever use it my self, it does make some things easier, like creating events.
So, click the Design button in the bottom of VS. Now you will see a visual representation of our page. We wish to add a Click event to the button, and this is very simply - just doubleclick the GreetButton, and you will be taken to the CodeBehind file of our page. As you can see, a fine new method has been added, called GreetButton_Click. If you have a look at the Default.aspx file (you need to go from Design view to Source view), you will see that an attribute has been added to our Button control, telling which method to call when the button is clicked. All this work done with a simple doubleclick.
Now lets add some code to our new event. We wish to use the text from the TextBox, on our good old Label with the "Hello, world!" text. This is also very simple, and all it requires is a single line of code:
HelloWorldLabel.Text = "Hello, " + TextInput.Text;
Run the project again (ctrl+F5), and you will see the our old page with a couple of new controls. The "Hello, world!" text is still there, because we set it in the Page_Load event. Now try entering a name in the textbox, and press the button. Voila, the text is changed, and we have just used our first control event. Notice how we can add code which is not necessarily called unless the user performs a specific task. This is different from the good old Classic ASP/PHP approach, but you will soon get used to it, and you will probably also come to like it a lot!