SharePoint (MOSS) AssetPicker (AssetURLSelector) customization

Couple of weeks back I was asked to customize the asset picker to suit client's requirements. The requirement was something like this : there is an ASP.net application running on application server, on click of a button, it should open up the assetpicker from MOSS (SharePoint environment). After the user selects a link and clicks on "OK" button in asset picker, the selected URL must be populated in a label.

The challenges faced are related to different server farms of hosted applications. asp.net application is on application server and assetpicker is on SharePoint server.

Below are the steps followed to achieve the desired result.

1. CALLINGPAGE.ASPX (this is an plain asp.net application page)

This page is part of asp.net application which will be hosted in application farm. This page consists of a “Browse” button on click of which the asset picker will be displayed. To achieve the desired result, we have put an iFrame in the HTML code. This iFrame will not be displayed to the user, but it will be used only to redirect the control to the AutoLaunchPickerDialog.aspx page.

Once the user clicks on the “Browse” button, OpenPicker() javascript function will be called. This javascript function will find the iFrame control and assign the source property with configurable value.

function OpenPicker()
{
 document.getElementById("assetSelectorFrame").src = 'GetConfigValueforURL';
}

The configurable value for the source of iFrame is defined in web.config file as following.

The CallingPage.aspx page also has a label “lblAssetURL” which will be assigned with the selected URL by “AssetSelectorSelected.htm” page.

2 AUTOLAUNCHPICKERDIALOG.ASPX PAGE

AutoLaunchPickerDialog.aspx page will put under the Layouts folder in 12 hive folder of SharePoint server. In this page an instance of AssetURLSelector is created. On Pre render event of this page, a method is called which will register a client start up script. This start up script will get the script to launch the asset picker by executing “GetClientLaunchPickerReference” method of asset URL selector. A client call back script is also registered for the asset URL selector. The asset URL selector’s “GetClientLaunchPickerReference” method expects a parameter of the URL. This URL can be a already selected URL or it will point to the current location of the page.

private AssetUrlSelector assetSelector;
private string ScriptGetAssetUrlValue = "";

protected override void OnPreRender(EventArgs e)
{
    base.OnPreRender(e);
    assetSelector = new AssetUrlSelector();
    GenerateAssetUrlSelectorLaunchScript();
}

private void GenerateAssetUrlSelectorLaunchScript()
{
if (Request.QueryString["SelectedPath"] == "")
{
  ScriptGetAssetUrlValue = "window.location.href";
}
else
{
  ScriptGetAssetUrlValue = "'" + Request.QueryString["SelectedPath"] + "'";
}
this.assetSelector.Page = this.Page;
this.assetSelector.ID = "assetUrlSelector";

this.assetSelector.ClientCallback = "function(newAssetUrl, newAssetText, configObject, returnedValue) { window.location = '" + Request.QueryString["targetUrl"] + "' +  newAssetUrl; }";

ClientScript.RegisterStartupScript(typeof(AutoLaunchPickerDialog), "Loading", "");
}

To the asset URL selector’s “ClientCallback” property, a javascript function is assigned. This function will assign newly selected URL to the location which is part of the query string. This query string will contain the location to redirect after the URL is selected. This will be the “AssetSelectorSelected.htm” page.

3 ASSETSELECTORSELECTED.HTM PAGE

The asset selector selected page is in application server. This html page will receive the selected URL as a query string from “AutoLaunchPickerDialog.aspx” page. On load of this page, a javascript function will be called. This function will read the query string and assign the value to the label in “CallingPage.aspx” page. Thus completing the entire process.

function Update()
{
 window.parent.document.getElementById("lblAssetURL").innerHTML = getQueryStringValue("selectedAssetURL");
}

function getQueryStringValue(key)
{
 searchString = window.location.search.substring(1);
 searchStringSplit = searchString.split("&");
 for (count=0;count