SQL Server - Sending XML string to SP

Creating XML format to send to Parameters as string to the SP

StringBuilder sbSites = new StringBuilder();
sbSites.Append("");

if (ddlManagingSite.SelectedValue != string.Empty)
{
sbSites.AppendFormat("", ddlManagingSite.SelectedValue);
}
else
{
foreach (ListItem item in ddlManagingSite.Items)
{
if (item.Text != "")
{
sbSites.AppendFormat("", item.Value);
}
}
}

sbSites.Append("");



SP need to look like this

CREATE PROC [dbo].[uspGetVacancyNoticeBoardByStateAndSite]

@vcSiteCode varchar(MAX)=''

AS

DECLARE @iDocSites INT
EXEC sp_xml_preparedocument @iDocSites OUTPUT, @vcSiteCode

SELECT
[ID],
[LastDataUpdateDate],
[LastDataUpdateBy]
FROM [dbo].[tblVacancyNoticeBoard]
WHERE [SiteCode] IN (SELECT SiteCodeID FROM OPENXML (@iDocSites, '/AllSITES/SiteCode', 1) WITH (SiteCodeID VARCHAR(5)))