title: Check All Checkbox items on DataGridView
body: <p>Here's the scenario.</p>
  
  <p>I have <code>checkbox</code>(Name:"Check All" ID:chkItems) and <code>datagridview</code>. And when I click on this checkbox, all checkboxes on the <code>datagridview</code> will also be checked.</p>
  
  <p>I've also added the checkbox column on the grid.</p>
  
  <pre><code>DataGridViewCheckBoxColumn CheckboxColumn = new DataGridViewCheckBoxColumn();
  CheckBox chk = new CheckBox();
  CheckboxColumn.Width = 20;
  GridView1.Columns.Add(CheckboxColumn);
  </code></pre>
  
  <p>Here is the code behind of the checkbox. There is a problem on the <code>row.Cell</code></p>
  
  <pre><code>private void chkItems_CheckedChanged(object sender, EventArgs e)
  {
      foreach (DataGridViewRow row in GridView1.Rows)
      {
          DataGridViewCheckBoxCell chk = e.row.Cells(0);
          if (chk.Selected == false)
          {
              row.Cells(0).Value = true;
          }
      }
  }   
  </code></pre>