title: How to reset bindingsource filter to nothing
body: <p>Using <code>BindingSource</code> on LINQ to SQL, and having implemented a <code>BindingList</code> in my project, I have to use a <code>Textbox</code> to filter rows in a <code>DataGridView</code>, so when I delete the textbox content, Filter should be reset to nothing.</p>
  
  <p>My code is as follows:</p>
  
  <pre><code>if (textBox1.Text.Length == 0)
  {
      productBindingSource.Filter = null;
  }
  else
  {
      productBindingSource.Filter = "ProductName = '" + textBox1.Text +"'";
      //productBindingSource.RemoveFilter();
  }
  productDataGridView.DataSource = productBindingSource;
  </code></pre>
  
  <p>But this does nothing, any idea, please?</p>