Add other ASP. net ajax Technologies

Add other ASP. net ajax Technologies

We can implement the <form> section similar to the one contained in TaskView. ascx. Furthermore, we can also describe each task item, but can convert a regular submission-based form into a form that supports AJAX technology. In this way, the edit and delete operations of task items can be implemented in the partial refresh state. This is explained in the sample code and will not be repeated here.

Next, I want to introduce how to add some scripts and add them to the UI of our sample program to create other HTML based on AJAX interaction. Specifically, I want to add a watermark effect to the text box. This effect provides a user-friendly prompt for user input. The watermark effect is displayed as long as there is no user input. When the user places the input focus in the text box, the watermark effect disappears.

Of course, Due to space limitations, we will not discuss the script itself too carefully. For more information about this script, see the source code of this article, but note that the watermark effect is implemented as a client Behavior of the ASP. net ajax framework that everyone may be familiar. Like any other behavior component, the text box used in our example is also associated with the DOM element, and it subscribes to related events caused by this element.

In traditional web form pages, I often directly use server controls that support AJAX functions, such as WatermarkExtender, and associate them with a server control. However, in this example, I use another extension method for rendering. Through this method, I can also create and initialize an instance of the script behavior component. The code snippet of the key part of the view after I update is provided below:

 
 

  
  
<% RenderBeginAjaxForm(Url.Action("Add"),  
  
  
new { Update="taskList, UpdateType="appendBottom",  
  
  
Highlight="True",  
  
  
Starting="startAddTask", Completed="endAddTask" }); %> 
  
  
<input type="text" name="name" id="nameTextBox" /> 
  
  
<% Ajax.Watermark("nameTextBox",  
  
  
new { watermarkText="[What do you need to do?]",  
  
  
watermarkCssClass="watermark"}); %> 
  
  
 
  
  
<input type="submit" name="addTask" value="Add Task" /> 
  
  
<% RenderEndForm(); %> 
 
 

The above extension method is quite simple to implement. In fact, it calls the ready-made AJAX framework. The following code defines the WatermarkBehavior class:

 
 

  
  
public static class WatermarkBehavior {  
  
  
public static void Watermark(this AjaxHelper ajaxHelper,
string id, object watermarkOptions) {  
  
  
ajaxHelper.RegisterScript("~/Views/Scripts/Watermark.js");  
  
  
ajaxHelper.RegisterScriptBehavior(id, "Ajax.Watermark", watermarkOptions);  
  
  
}  
  
  
} 
 
 

Of course, we can also control the above encoding in more detail, but here only shows the code snippets that provide the core part of the Script Function for collecting and registering, and generate them to the page, then, instantiate the behavior object and associate it with the corresponding DOM elements, and pass it to the selection provided by the view to customize the specific instance introduction to add ASP. other AJAX technologies.

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