How do I update details of the user that is logged in using sessions C# ASP.NET

<pre> protected void btnTenantSave_Click(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            //Creating a connection to my database using the connection string
            string cs = System.Configuration.ConfigurationManager.ConnectionStrings["rent-dbConnectionString1"].ConnectionString;
        SqlConnection con = new SqlConnection(cs);
        //preparing a query which will update the data in the database with the data entered into the textboxes
        SqlCommand cmd = new SqlCommand("UPDATE Tenants SET Tenant_FullName='" + this.txtTenantFullName.Text + "',Tenant_Email='" + this.txtTenantEmail.Text + "',Tenant_TelNum='" + this.txtTenantTelNum.Text + "',Tenant_EmName= '" + this.txtTenantEmName.Text + "',Tenant_EmNum= '" + this.txtTenantEmNum.Text + "',Tenant_WorkStatus= '" + this.txtWorkstatus.Text + "'Where Tenant_Email='" + Session["TenantLogin"] + "';", con);
        con.Open();
        cmd.ExecuteNonQuery();
        con.Close();
        }
        Response.Redirect("TenantIndex.aspx");
       
    }