SoFunction
Updated on 2025-04-08

After clicking the Submit button, the value of DropDownList becomes the default value to achieve analysis

After clicking the Submit button, all control values ​​on the page that are bound to the database are restored to the default value

The reason is to write the binding function loadData() in

if(!IsPostBack)
{
Your binding function;
}
Otherwise, the page will be reloaded and the values ​​of all controls become initial values.

IsPostBack is a property of the Page class that has a bool type, which is used to determine whether the current page is loading in response to client postback or is being loaded and accessed for the first time.

When IsPostBack=true, it is expressed as loading in response to client postback.
When IsPostBack=false, it means it is being loaded and accessed for the first time.

That is to say, only if IsPostBack=false is executed, bind the function, so that it will not cause page overloading and lead to page control initialization.

IsPostBack Introduction:
/en-us/library/
/doc/