display error or success message when using c# foreach statement

I am using C#. How can I display a success message if all data were submitted, or an error message and break the loop in case there was an error during the foreach loop?

This is my try, but I don't know the best way to display the messages:

protected void btnUpdate_Click(object sender, EventArgs e)
{
    DataDTO data = new DataDTO();
    BaseDAO coexion = new BaseDAO();

    foreach (GridViewRow row in this.GridView1.Rows)
    {
        data.lblId = ((Label)row.FindControl("lblId")).Text;


        try
        {
            coexion.update_database(data);
        }
        catch
        {
            // Display error message and break loop
        }
    }

    GridView1.EditIndex = -1;
    LoadGrid();
    // Display success message
}