title: How to set TargetNullValue as folderpath in binding?
body: <pre><code>&lt;TextBox Grid.Column="2"  Height="25"   IsReadOnly="True" TextAlignment="Right"  Text="{Binding ElementName=Mygroups, TargetNullValue= 'C:\myfolder1\mysubfolder1',Path=DataContext.FoldernameWithPath,UpdateSourceTrigger=PropertyChanged,Mode=TwoWay}"  /&gt;
  &lt;Button Grid.Column="3" Grid.Row="1"  Content="Browse"    Height="25" VerticalAlignment="Bottom"   MinWidth="47"   Command="{Binding ElementName=Mygroups,Path=DataContext.OpenFolderCommand}" CommandParameter="{Binding}" /&gt;
  </code></pre>
  
  <p>Before the user clicks the <strong>browse</strong> button,I need to bind the <strong>Textbox</strong> with default folderpath which is mentioned in <strong>TargetNullValue</strong>. But in my case it is binding like this <strong>C:myfolder1mysubfolder1</strong></p>
  
  <p>What I should do to bind the textbox like <strong>C:\myfolder1\mysubfolder1</strong> ?</p>