protected string ChildCompanies(Company c)
    {
        System.Text.StringBuilder sb = new System.Text.StringBuilder();
        Company parent = new Company(c.ParentId);
        CompanyCollection cc = new CompanyCollection();
        cc.Add(c);
        if (parent.CanIEdit(CurrentUser))
        {
            sb.AppendLine("[ ");
            sb.Append("{ attributes: { id : \"" + parent.ID + "\" }, data: \""+parent.CompanyName+"\"");
            sb.Append(", state: \"open\", children: " + ChildCompanies(cc));
            sb.Append("}");
            sb.AppendLine("]");
        }
        else
        {
            sb.Append(ChildCompanies(cc));
        }
        return sb.ToString();
    }