title: Filtering combo box items using text search in C# windows form
body: <p>I'm Trying to filter a combo box using its text property in all characters of Items not only Beginning of them. I'm trying below code in TextChanged event of my combo box. but unfortunately combo box resets after entering any key:    </p>
  
  <pre><code>    private void cmbCompany_TextChanged(object sender, EventArgs e)
      {
          string QueryCompany = string.Format("select id,title from acc.dl where title LIKE '%" + cmbCompany.Text + "%' union select null , null order by title");
          SqlDataAdapter DA1 = new SqlDataAdapter(QueryCompany, con);
          DataTable DT1 = new DataTable();
          DA1.Fill(DT1);
          cmbCompany.DisplayMember = "Title";
          cmbCompany.ValueMember = "id";
          cmbCompany.DataSource = DT1;
      }
  </code></pre>
  
  <p>connection string "con" is defined and opened. 
  thanks for your helps.</p>