title: Problem with filtering DataGrid
body: <p>I have bound my DataGrid to a DataTable  and only few of the details are displayed in the grid. When I wanted to filter the DataGrid I created a View with my DataGrid's ItemsSource. 
  Code:</p>
  
  <pre><code>  Dim myView As ICollectionView = CollectionViewSource.GetDefaultView(MyDGrid.ItemsSource)
    myView.Filter = New Predicate(Of Object)(AddressOf filterFunc1)
  </code></pre>
  
  <p>Now When I do the search, the non-displayed fields are also included in the search. </p>
  
  <pre><code>Public Function filterFunc1(ByVal obj As Object) As Boolean
      Dim filStr As String = "*" &amp; TextBox1.Text &amp; "*"
      For Each item As String In obj.Row.ItemArray
          **If item.ToLower Like filStr.ToLower Then**
              Return True
          End If
      Next
      Return False
  End Function
  </code></pre>
  
  <p>Also I Have ComboBox fields in the DataGrid which are loaded separately from other DataTable's. Now I cant Include them in the search.</p>
  
  <p>A screenshot from my App:
  <img src="https://i.stack.imgur.com/W821W.png" alt="A screenshot from my App:"></p>
  
  <p>So how do I make a search that includes only the Text from Displayed part. </p>
  
  <p>EDIT: Also how do I skip searching the null valued fileds? 'cause thats causing an exception in my case.    </p>