Flex SQLite删除功能

Question

I wanted to delete a selected Item from a List control but can't. What's wrong with my code:

[Bindable]private var dp:ArrayCollection = new ArrayCollection();
private var conn:SQLConnection;

protected function Delete(event:MouseEvent):void    {
    Stmt = new SQLStatement();
    Stmt.sqlConnection = conn;
    Stmt.text = "DELETE FROM UserTable WHERE firstName="+listBox.selectedIndex;
    Stmt.execute();
}

<s:List id="listBox" itemRenderer="UserRenderer"></s:List>



In UserRenderer:

<s:ItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009"
                xmlns:s="library://ns.adobe.com/flex/spark">

    <s:Label text="{data.lastName}, {data.firstName}, {data.id}"/>

</s:ItemRenderer>

Answer 1

List#selectedIndex refers to the position of the selected item in the dataprovider. The first element will have index 0, the second index 1 and so on. If no item is selected, selectedIndex will be -1 .

If you want to select or delete by firstName - as you do in your query - you will have to pass in a valid first name instead of an index position. You can do this with the List#selectedItem property. Also don't forget the single quotes in your query if you're not using query params.

"DELETE FROM UserTable " +
"WHERE firstName = '" + listBox.selectedItem.firstName + "'";

You weren't asking for this, but I'll tell you anyway: for security reasons you should use query params when using variables in your queries. One way to achieve this in ActionScript is:

stmt.parameters[0] = listBox.selectedItem.firstName;
stmt.text = "DELETE FROM UserTable WHERE firstName = ?";

(no single quotes required here)