C# – Clear values from people editor SharePoint control

You didn't specify the version of SharePoint but the following explanation applies to SharePoint 2007 and was not confirmed in 2010.

The people picker's value can be set by clicking the 'Check Names' icon or the 'Browse' icon.

If you click the 'Check Names' icon which is an anchor tag, the onclick event invokes 'WebForm_DoCallback' which will asynchronously make an HTTP request to the SharePoint server to validate the name entered into the people picker.

Following is the WebForm_DoCallback signature:

function WebForm_DoCallback(eventTarget, 
eventArgument, 
eventCallback, 
context, 
errorCallback, 
useAsync){
...
}

One of the WebForm_DoCallbacks argument that that you will be most interested in is 'eventTarget', the people picker text area. You will also be interested in 'eventCallback' as it's the callback method invoked after the async HTTP request returns. In this case, it's 'EntityEditorHandleCheckNameResult(result, ctx)' defined in core js.

Following is the definition of the EntityEditorHandleCheckNameResult function

function EntityEditorHandleCheckNameResult(result, ctx)
{
   EntityEditorClearWaitCursor(ctx);
   EntityEditorCallback(result, ctx);
} 

Notice that it delegates the event handling to the EntityEditorCallback method. This is also the case if you click the 'Browse' icon which opens a dialog for you to find and select a user. The 'Browse' icon obviously leverages a different call stack but as they both rely on EntityEditorCallback, I will focus on this method as the solution works when you click 'Check Names' or 'Browse'.

To execute your code after EntityEditorCallback is invoked, you can leverage the following code:

var invokeAfterEntityEditorCallback =  function(func) {
    var old__EntityEditorCallback = EntityEditorCallback;
    if (typeof EntityEditorCallback != 'function') {
        EntityEditorCallback = func;
    } else {
        EntityEditorCallback = function(result, ctx) {
            old__EntityEditorCallback(result, ctx);
        func(result, ctx);
        }
    }
};

Following is a custom people picker event handler which alerts the result and the ID of the people picker text area:

function onPeoplePickerFieldSet(result, ctx){
    alert(result);
    alert(ctx); 
}

Following is logic that will allow the onPeoplePickerFieldSet method to be invoked after the people picker name is checked or selected from the browse dialog. Also, this statement can be invoked in the document.ready event handler if you are using jQuery.

invokeAfterEntityEditorCallback(onPeoplePickerFieldSet);

The 'result' argument of the onPeoplePickerFieldSet method is an XML result indicating successful validation as well as the domain quailified user name. The following XML is an example resulting from click the 'Check Names' icon:

<Entities Append="False" Error="" Separator=";" MaxHeight="3">
   <Entity Key="HOLLOWAY\csteel" DisplayText="Craig Steel" IsResolved="True" Description="HOLLOWAY\csteel">
      <ExtraData>
         <ArrayOfDictionaryEntry xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
            <DictionaryEntry>
               <Key xsi:type="xsd:string">DisplayName</Key>
               <Value xsi:type="xsd:string">Craig Steel</Value>
            </DictionaryEntry>
            <DictionaryEntry>
               <Key xsi:type="xsd:string">Email</Key>
               <Value xsi:type="xsd:string">csteel@holloway.net</Value>
            </DictionaryEntry>
            <DictionaryEntry>
               <Key xsi:type="xsd:string">SPUserID</Key>
                <Value xsi:type="xsd:string">16</Value>
            </DictionaryEntry>
            <DictionaryEntry>
               <Key xsi:type="xsd:string">PrincipalType</Key>
               <Value xsi:type="xsd:string">User</Value>
            </DictionaryEntry>
         </ArrayOfDictionaryEntry>
      </ExtraData>
      <MultipleMatches />
   </Entity>
</Entities>

The 'ctx' argument is the ID of the people picker text area and can be used in a jQuery selector statement.

That's it!

Hope this code is helpful for you..

public void btnSave_Click(object sender, System.EventArgs e)
{
   ….
   //where userPicker is Id of People picker control
   PickerEntity pe = (PickerEntity)userPicker.Entities[0];  
   string username = pe.Description;
   …
}