Asp Net Membership 4.5.2 Register Account

Hi,

When you register a new account using asp net membership 4.5.2, they don't allow spaces.  I want to be able to register an account with spaces.  How do you change the register process to allow for this (spaces).

ASPX

<h2><%: Title %>.</h2><p class="text-danger"><asp:Literal runat="server" ID="ErrorMessage" /></p><div class="form-horizontal"><h4>Create a new account.</h4><hr /><asp:ValidationSummary runat="server" CssClass="text-danger" /><div class="form-group"><asp:Label runat="server" AssociatedControlID="UserName" CssClass="col-md-2 control-label">User name</asp:Label><div class="col-md-10"><asp:TextBox runat="server" ID="UserName" CssClass="form-control" /><asp:RequiredFieldValidator runat="server" ControlToValidate="UserName"
                    CssClass="text-danger" ErrorMessage="The user name field is required." /></div></div><div class="form-group"><asp:Label runat="server" AssociatedControlID="Password" CssClass="col-md-2 control-label">Password</asp:Label><div class="col-md-10"><asp:TextBox runat="server" ID="Password" TextMode="Password" CssClass="form-control" /><asp:RequiredFieldValidator runat="server" ControlToValidate="Password"
                    CssClass="text-danger" ErrorMessage="The password field is required." /></div></div><div class="form-group"><asp:Label runat="server" AssociatedControlID="ConfirmPassword" CssClass="col-md-2 control-label">Confirm password</asp:Label><div class="col-md-10"><asp:TextBox runat="server" ID="ConfirmPassword" TextMode="Password" CssClass="form-control" /><asp:RequiredFieldValidator runat="server" ControlToValidate="ConfirmPassword"
                    CssClass="text-danger" Display="Dynamic" ErrorMessage="The confirm password field is required." /><asp:CompareValidator runat="server" ControlToCompare="Password" ControlToValidate="ConfirmPassword"
                    CssClass="text-danger" Display="Dynamic" ErrorMessage="The password and confirmation password do not match." /></div></div><div class="form-group"><div class="col-md-offset-2 col-md-10"><asp:Button runat="server" OnClick="CreateUser_Click" Text="Register" CssClass="btn btn-default" /></div></div></div>

CS

protected void CreateUser_Click(object sender, EventArgs e)
    {
        var manager = new UserManager();
        var user = new ApplicationUser() { UserName = UserName.Text };
        IdentityResult result = manager.Create(user, Password.Text);
        if (result.Succeeded)
        {
            IdentityHelper.SignIn(manager, user, isPersistent: false);
            IdentityHelper.RedirectToReturnUrl(Request.QueryString["ReturnUrl"], Response);
        }
        else
        {
            ErrorMessage.Text = result.Errors.FirstOrDefault();
        }
    }