SQL Server Management Studio上的数据未更新

我在Visual Studio 2012上的代码有问题。它应该更新可以在我的SQL Server Management Studio上找到的记录。除了这次更新之外，所有内容都与数据库一致。请看一下我的代码：

protected void btnUpdate_Click(object sender, EventArgs e)
    {
        con.Open();
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        if (txtPassword.Text == "")
        {
            cmd.CommandText = "UPDATE Users SET EmailAddress=@EmailAddress, FirstName=@FirstName, " +
                "LastName=@LastName, Street=@Street, Municipality=@Municipality, City=@City, ZipCode=@ZipCode, ContactNo=@ContactNo, Image=@Image " +
                "WHERE UserID=@UserID";
        }
        else
        {
            cmd.CommandText = "UPDATE Users SET Password=@Password, EmailAddress=@EmailAddress, FirstName=@FirstName, " +
               "LastName=@LastName, Address=@Address, Street=@Street, Municipality=@Municipality, City=@City, ZipCode=@ZipCode, ContactNo=@ContactNo, Image=@Image " +
               "WHERE UserID=@UserID";
        }
        cmd.Parameters.Add("@EmailAddress", SqlDbType.NVarChar).Value = txtEmail.Text;
        cmd.Parameters.Add("@Password", SqlDbType.NVarChar).Value = Helper.CreateSHAHash(txtPassword.Text);
        cmd.Parameters.Add("@FirstName", SqlDbType.VarChar).Value = txtFN.Text;
        cmd.Parameters.Add("@LastName", SqlDbType.VarChar).Value = txtLN.Text;
        //cmd.Parameters.Add("@Address", SqlDbType.NVarChar).Value = txtAddress.Text;
        cmd.Parameters.Add("@Street", SqlDbType.NVarChar).Value = txtStreet.Text;
        cmd.Parameters.Add("@Municipality", SqlDbType.NVarChar).Value = txtMunicipality.Text;
        cmd.Parameters.Add("@City", SqlDbType.NVarChar).Value = txtCity.Text;
        cmd.Parameters.Add("@ZipCode", SqlDbType.NVarChar).Value = txtZipCode.Text;
        cmd.Parameters.Add("@ContactNo", SqlDbType.NVarChar).Value = txtContact.Text;
        cmd.Parameters.Add("@UserID", SqlDbType.Int).Value = Session["UserID"].ToString();
        if (fuImage.HasFile)
        {
            cmd.Parameters.Add("@Image", SqlDbType.Text).Value = "~/images/" + fuImage.FileName;
            fuImage.SaveAs(Server.MapPath("~/images/" + fuImage.FileName));
        }
        else
        {
            cmd.Parameters.Add("@Image", SqlDbType.Text).Value = imgAvatar.ImageUrl;
        }
        Helper.AddLog(Session["UserID"].ToString(), "Update", "Updated a User");
        Response.Redirect("Default.aspx");
    }
    protected void btnCancel_Click(object sender, EventArgs e)
    {
        Response.Redirect("Default.aspx");
    }

cmd.ExecuteNonQuery();

cmd.ExecuteNonQuery();