Moving Items from one Listbox to another.

Introduction

This Article is usefull to move the list items between 2 listbox or combo or dropdown, it will also give an alert message if no items of the listbox are selected.

Background

This code can be used in any web applications, in the javascript part.

Using the code

Assumptions:

The name of Buttons are assumed to be btnMoveRight and btnMoveLeft

The name of the ListBox are assumed to be ListBox1 and ListBox2

Code for the javascript function:

function fnMoveItems(lstbxFrom,lstbxTo)
{
 var varFromBox = document.all(lstbxFrom);
 var varToBox = document.all(lstbxTo); 
 if ((varFromBox != null) && (varToBox != null)) 
 { 
  if(varFromBox.length < 1) 
  {
   alert('There are no items in the source ListBox');
   return false;
  }
  if(varFromBox.options.selectedIndex == -1) // when no Item is selected the index will be -1

  {
   alert('Please select an Item to move');
   return false;
  }
  while ( varFromBox.options.selectedIndex >= 0 ) 
  { 
   var newOption = new Option(); // Create a new instance of ListItem 

   newOption.text = varFromBox.options[varFromBox.options.selectedIndex].text; 
   newOption.value = varFromBox.options[varFromBox.options.selectedIndex].value; 
   varToBox.options[varToBox.length] = newOption; //Append the item in Target Listbox

   varFromBox.remove(varFromBox.options.selectedIndex); //Remove the item from Source Listbox 

  } 
 }
 return false; 
}

code for calling the javascript function:
There are 2 methods of calling the javascript code, they are as under.
1.  Add this code in the pageload
btnMoveRight.Attributes.Add("onclick","return fnMoveItems('ListBox1','ListBox2')");
btnMoveLeft.Attributes.Add("onclick","return fnMoveItems('ListBox2','ListBox1')");
2.  Add this code in the HTML
<input type = "button" id = "btnMoveRight" onclick = "fnMoveItems('ListBox1','ListBox2')">
<input type = "button" id = "btnMoveLeft" onclick = "fnMoveItems('ListBox2','ListBox1'">

Points of Interest

Let me know if you have any queries.

History

New Article on AJAX to be added shortly. :-)