title: Change the Value of Cell of DataGridView from other Form
body: <p>I have 2 forms:</p>
  
  <ol>
  <li><p><code>Form1</code> contains <code>DataGridView</code> controls</p></li>
  <li><p><code>Form2</code> contains <code>Textbox</code> controls (are in mode read only), checkBox and Button.</p></li>
  </ol>
  
  <p>When I select a <code>DataGridView</code> Row it will show me Form2 and display their values in TextBoxes. Everything seems better just now.
  What I want know is after displaying data in textboxes, I check the RadioButton then click the button it will return to Form1 of the selected Row and <strong>Change the value of Cell 4</strong> automatically.</p>
  
  <p>Here there is My code:</p>
  
  <p>Form1 </p>
  
  <pre><code>private void dataGridView1_RowHeaderMouseDoubleClick(object sender, DataGridViewCellMouseEventArgs e)  
     {  
         DataGridViewCell cell = null;  
         foreach (DataGridViewCell selectedCell in dataGridView1.SelectedCells)  
         {  
             cell = selectedCell;  
             break;  
         }  
         if (cell != null)  
         {  
             DataGridViewRow row = cell.OwningRow;  
             string objet = row.Cells[0].Value.ToString();  
             string objectif = row.Cells[1].Value.ToString();  
             string date = row.Cells[2].Value.ToString();  
             string commentaire = row.Cells[3].Value.ToString();  
             string client = row.Cells[5].Value.ToString();  
             string commercial = row.Cells[6].Value.ToString();  
  
             Détails_RDV détails = new Détails_RDV();  
  
             détails.obj = objet;  
             détails.objectif = objectif;  
             détails.date = date;  
             détails.comm = commentaire;  
             détails.clt = client;  
             détails.commer = commercial;  
  
             détails.Show();  
  
         }  
     }  
  </code></pre>
  
  <p>Form2</p>
  
  <pre><code>public partial class Détails_RDV : Form  
  {  
      public string obj ;  
      public string objectif;  
      public string date;  
      public string comm;  
      public string clt ;  
      public string commer;  
  
      public Détails_RDV()  
      {  
          InitializeComponent();  
  
      }  
  
      private void Détails_RDV_Load(object sender, EventArgs e)  
      {  
  
          txtObjet.Text = obj;  
          txtObjectif.Text = objectif;  
          txtDate.Text = date;  
          txtCommerci.Text = commer;  
          txtClient.Text = clt;  
          txtCommentaire.Text = comm;  
      }  
  
      private void btnValider_Click(object sender, EventArgs e)  
      {  
          if (checkEffectue.Checked == true)  
          {  
             //What should I write here??
               Liste_RDV lrdv = new Liste_RDV();
               lrdv.Show();
  
          }  
      }  
  </code></pre>
  
  <p>How Can I do That ?</p>