单据界面自定义按钮如何弹出允许多选的F7界面，并抓取返回

代码参考如下：
//弹出F7界面
//FLookUpType=3表示F7的是BOS单据，如果是核算项目应该用1
//FClassTypeID=1012002表示你要F7是哪个界面，这里是商机
void m_BillInterface_OnBarItemClick(object Sender, BarItemClickEventArgs e)
{
switch (e.BarName.ToUpper())
{
case "MNUEDITCOMMENT":
{
StringBuilder sBuilder = new StringBuilder();
sBuilder.AppendFormat("EXTBOS/LookUp/BillLookUpContent.aspx?FLookUpType=3&FClassTypeID=1012002&FProperty=null&IsMultiSel=1&FPageID={0}", new Guid().ToString());
sBuilder.AppendFormat("??dialogWidth:750px; dialogHeight:565px;");
sBuilder.AppendFormat("resizable:no;scroll: no; status: no; unadorned : no; help : no;Minimize=no;Maximize=no;");
m_BillInterface.ShowCustomePage(e.BarName, sBuilder.ToString());

}
break;
}
}

//获取返回值
void m_BillInterface_AfterShowCustomerPage(object sender, Kingdee.K3.BOS.PlugInModel.Bill.Events.AfterShowCustomerPageEventArgs e)
{
if (e.SenderId.ToUpper() == "MNUEDITCOMMENT")
{
string s = e.RetValue;
//有需要转成数据包，需引用命名空间using System.Web.Script.Serialization;在微软的System.Web.dll
JavaScriptSerializer ser = new JavaScriptSerializer();
Dictionary dRet = ser.Deserialize(e.RetValue);
}
}