title: Edit dataGridView cell on C#
body: <p>I tried to change value of cell in <code>DataGridView</code> on c#. I even cannot write a "Hello" in cell. Where is the error. What is missing part?</p>
  
  <p>When I click the button, nothing changes. No error, no changes.</p>
  
  <pre><code>private void button1_Click(object sender, EventArgs e)
  {
      dataGridView1.ReadOnly = false;
      dataGridView1.BeginEdit(true);
      dataGridView1.Rows[0].Cells[0].Value = "Hello";
      dataGridView1[1, 1].Value = "Hello";
  }
  </code></pre>