title: DataGridView How to check if a cell is empty?
body: <p>I'm developing a program that contains a DataGridView whitin a form, and I'm importing data to this DataGridView from a XML file.
  Inside this DataGridView, I'm able to add, edit and delete this data and save this changes to the XML file when a button is clicked. (There are two columns.)
  My issue here is that I need to check if any cell is empty when the button is clicked, and in that case, show up a MessageBox indicating this and do not let me save this changes.</p>
  
  <p>I've tried for loops and more, and couldn't find anything helpful.
  Hope someone can help me! Thanks </p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.ComponentModel;
  using System.Data;
  using System.Drawing;
  using System.Linq;
  using System.Text;
  using System.Windows.Forms;
  using System.Xml;
  
  namespace Sullair
  {
  public partial class IPs : Form
  {
      public IPs()
      {
          InitializeComponent();
      }
  
      private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
      {
  
      }
  
      private void IPs_Load(object sender, EventArgs e)
      {
          try
          {
              DataSet ds = new DataSet();
              ds.ReadXml(@"C:\Users\Administrador\source\repos\Sullair\schema.xml");
              dataGridView1.DataSource = ds.Tables[0];
          }
          catch (Exception ex)
          {
              MessageBox.Show(ex.ToString());
          }
      }
  
      private void Save()
      {
          DataTable db = (DataTable)dataGridView1.DataSource;
          db.WriteXml(@"C:\Users\Administrador\source\repos\Sullair\schema.xml");
      }
  
      private void btnSave_Click(object sender, EventArgs e)
      {
          Save();   
      }
  
  }
  }
  </code></pre>