Accessing Client Changes at the Server

Client-side changes are available on the server-side after postback. You can use the ClientChanges property of the RadDropDownList to access them. The ClientChanges property returns a collection of objects of type ClientOperation. An operation has two properties:

• Item - the item which has been affected by the client operation;

• Type - the type of the operation which is one of the following four cases:

  • Update - when a property is set on the client through methods such as set_text(), set_value(), enable(), disable(), etc.: dropdownlistItem.disable();

  • Remove - when the remove client method is called: dropdownlist.get_items().remove(dropdownlistItem);

  • Insert - when the add client method is called: dropdownlist.get_items().add(dropdownlistItem);

  • Clear - when the clear method is called: dropdownlist.get_items().clear();

Note that you need to call the trackChanges() and commitChanges() client methods of RadDropDownList in order to be able to access the changes on the server via the ClientChanges property.

Example:

The code snippet below enumerates through all operations in the ClientChanges collection and utilizes both the Item and Type properties.

C#

	     	
foreach (ClientOperation<DropDownListItem> operation in RadDropDownList1.ClientChanges)
{
    DropDownListItem item = operation.Item;
    switch (operation.Type)
    {
        case ClientOperationType.Insert:
            break;
        case ClientOperationType.Remove:
            break;
        case ClientOperationType.Update:
            UpdateClientOperation<DropDownListItem> update = operation as UpdateClientOperation<DropDownListItem>;
            break;
        case ClientOperationType.Clear:
            break;
    }
} 
				

VB.NET

For Each operation As ClientOperation(Of DropDownListItem) In RadDropDownList1.ClientChanges
Dim item As DropDownListItem = operation.Item
 Select Case operation.Type
  Case ClientOperationType.Insert
   Exit Select
  Case ClientOperationType.Remove
   Exit Select
  Case ClientOperationType.Update
Dim update As UpdateClientOperation(Of DropDownListItem) = TryCast(operation, UpdateClientOperation(Of DropDownListItem))
   Exit Select
  Case ClientOperationType.Clear
   Exit Select
 End Select
Next 
				

See Also

• RadDropDownList client-side Object