title: WPF combobox auto highlighting on first letter input
body: <p>Hi I have a <code>ComboBox</code> in WPF</p>
  
  <pre><code>&lt;ComboBox x:Name="Select_Food" Grid.ColumnSpan="3" Margin="10"  Text="" IsEditable="True"  
                ItemsSource="{Binding}" KeyUp="Select_Food_KeyUp" IsTextSearchEnabled="false"  /&gt;
  </code></pre>
  
  <p>I am getting information from a database as options while the user types in the text box. currently everything works but the only problem is that when I type a first letter in the textbox, that letter is automatically highlighted provided any of the items in the list start with that letter. Because of this, any further typing overwrites the first letter. This is a problem. How do I stop the this initial highlight. I am trying to achieve a "google-search-like" combobox. </p>
  
  <p>this is the code. help please. </p>
  
  <pre><code> // While typing this function is called on every keyup stroke
      private void Select_Food_KeyUp(object sender, KeyEventArgs e)
      {
          try
          {
              SqlCeCommand command = new SqlCeCommand("SELECT FOODITEM_RS FROM FOOD WHERE FOODITEM_RS LIKE @fitem", thisConnection);
              command.Parameters.AddWithValue("@fitem", "%" + Select_Food.Text + "%");
              SqlCeDataAdapter da = new SqlCeDataAdapter(command);
              DataSet ds = new DataSet();
              thisConnection.Open();
              da.Fill(ds, "FOOD");
              Select_Food.ItemsSource = ds.Tables[0].DefaultView;
              Select_Food.DisplayMemberPath = ds.Tables[0].Columns["FOODITEM_RS"].ToString();
  
          }
          catch (SqlCeException x)
          {
              MessageBox.Show(x.ToString());
          }
          //Open dropdown menu
          Select_Food.IsDropDownOpen = true;
  
          thisConnection.Close();
  
      }
  </code></pre>