Setting CommandArgument for a Gridview

I want to set a CommandArgument for a Gridview but if I run the programm an error occured.

Here is my ButtonField declaration:

<asp:ButtonField Text="Löschen" CommandName="Deleterecord"  ButtonType="Button" CommandArgument=<% Eval("userId") %>  /> 

and this is the error:

Parser Error Message: Literal content ('<asp:ButtonField Text="Löschen" CommandName="Deleterecord"  ButtonType="Button" CommandArgument=') is not allowed within a 'System.Web.UI.WebControls.DataControlFieldCollection'.

EDIT:

with these block of code I fill my Gridview:

protected void Button2_Click(object sender, EventArgs e)
        {
            Guid g = Guid.Parse("ef7a9f97-6a9a-44c6-ac38-82a5d06c394e");
            RoutesManager rm = new RoutesManager(g);
            rm.GetAllRoutes();
            List<Route> result;
            result=rm.GetAllRoutes();

            GridView1.DataSource = result;
            GridView1.DataBind();

        }

and this is GetallRoutes:

 public List<Route> GetAllRoutes()
        {
            var inputParams = new Dictionary<string, object>();
            var xmlHelper = new XmlHelper();
            var result = new List<Route>();

            inputParams.Add("UserId", _userId);

            DataTable dt = _dbhelper.Select("SELECT * FROM ROUTES WHERE UserId=@UserId", inputParams);

            foreach (DataRow row in dt.Rows)
            {
                var xmlDoc = new XmlDocument();
                xmlDoc.LoadXml(row[XmldocPosition].ToString());               
                result.Add(xmlHelper.ConvertXmlDocumentToRoute(xmlDoc.ToXDocument()));
            }

             return result;

}

My grid view full with this block of code ,I put a link button in my Gridview for each Row and I want if the user click this button only this row is deleted from DB and Gridview