Object is not an object instance en DataGridView
<p>I'm trying to bring a list of SQL and it will be load into a datagridview. After that, some fields must be DataGridViewComboBoxColumn type, so the user can select any options from the combobox columns. This is the code I have done:</p>

<pre><code>public async void ConfigurarGrilla()
    {
        try
        {
            var responseArea = await servicio.AreaGetAllAsync();
            var responseEmpresa = await servicio.EmpresaGetAllAsync();

            if (responseArea.IsValid &amp;&amp; responseEmpresa.IsValid)
            {
                listaArea = responseArea.Value;
                listaEmpresa = responseEmpresa.Value;

                dgvArticulos.AutoGenerateColumns = false;

                DataGridViewComboBoxColumn dtColumn = dgvArticulos.Columns["CodArea"] as DataGridViewComboBoxColumn;
                dtColumn.DataSource = listaArea;
                dtColumn.DisplayMember = "CodArea";

                DataGridViewComboBoxColumn dtColumn2 = (DataGridViewComboBoxColumn)dgvArticulos.Columns["RazonSocial"] as DataGridViewComboBoxColumn;
                dtColumn2.DataSource = listaEmpresa;
                dtColumn2.DisplayMember = "RazonSocial";

                LoadDocumento();
            }
            else
            {
                MessageBox.Show(responseArea.ErrorMensaje);
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show("Ocurrio un error " + ex.Message, "Aviso", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }
</code></pre>

<p>The responseArea.Value and responseEmpresa.Value methods bring the list from the BD, they contain information when I debug, but in line dtColumn.DataSource = listaArea is where I get the error</p>

<blockquote>
  <p>"Object reference not set to an instance of an object"</p>
</blockquote>

<p>I don't know what is the problem. All my objects have been  initialized</p>