Asp. NET to create and use Web Components dynamically based on XML (III)

asp.net|web|xml| Create | dynamic ASP. NET to create the use of Web Components dynamically based on XML

Three

Author: Shing

Iv. using dynamically created Web Components

If you want to use this component after you have created the Web Component dynamically, you can use the following statement

String sequencelabelid= "SEQUENCEDATATB" +icount. ToString ();

Label sequencelabel= (label) Myplaceholder.findcontrol (Sequencelabelid);

Sequencelabel.text= "..."

... ...















Where sequencelabelid is the ID number of the component to use, the Myplaceholder.findcontrol () method returns the object of type control, using (Label) to cast the type to the label type. Then you can do whatever you need to do with this object you want to operate. such as changing the properties of a component, and so on.

A special note is that using the above statement to use a dynamically created Web component has the premise that the page cannot be refreshed. If the page is refreshed and you do not re-create the component after the page has been refreshed. Use the above statement in your program to use a dynamically created Web component, and you will get an error while the program is running. This error occurs because the dynamically created Web Component does not exist after the page has been refreshed. There is such a problem in the author's procedure. Because the author of the process of thinking is

1. Read XML file

2. Dynamically create Web Components based on read information and assign values to their text properties

3. Allows users to modify the text properties of a dynamically created Web component.

4, after the user submits the modification, wants to write the modified attribute to the XML file

However, when the user submits the change, the page is refreshed. So how do you get the modified attributes?

The author uses the following method in the program:

private void Summitbutton_click (object sender, System.EventArgs e)

{

... ...

Writes the measurement point information that the user fills in to the array

for (int icount=1;icount<=int. Parse (viewstate["Totalnum"). ToString ()); icount++)

{

... ...

String nametbid= "Nametb" +icount. ToString ();

String Nametbtext=request.form[nametbid]. ToString ();

Namestr[icount]=nametbtext;



}

... ...

}

































Where nametbid is the ID number of the Web Component to use. When the page is refreshed, although the dynamically created Web Component does not exist, the request object has saved the information for the Web component, so you can still get the modified information.

If you want to still display the dynamically created Web component after the page is refreshed, you need to invoke the function that created the Web Component again in Page_Load (object sender, System.EventArgs e) and use Request.form[id] Assign the modified value to the corresponding component. Keep in mind that the function that creates the Web component is placed in the IF (IsPostBack) {}.