title: Conditional filter expression in asp.net?
body: <p>So I have two filtering objects. One is a drop down list, which chooses the group of users to look at. Next is the user search box. I would like to use this to filter the results further so that you can search for a user <strong>in the chosen group</strong>.
  I have tested the group filter and it works on it's own (without the inclusion of the searchbox).</p>
  
  <p>Now, the problem I face is the default view. What I want to <strong>also</strong> be able to do is choose a group without putting in a user, giving me the complete list of users in that group. Then if I want to filter it down more I would use the searchbox.</p>
  
  <p>Currently I have to use the searchbox in order to have any results show. I suspect it's the default value I have set for the searchbox control parameter, but I am unsure how to fix it (I have tried putting the wildcard in but then it doesn't filter by group anymore)</p>
  
  <p>Here is the filter expression:</p>
  
  <pre><code>FilterExpression="(([Field1] = {0}) AND ([Field2] LIKE '%{1}%'))"
  </code></pre>
  
  <p>And here are the parameters:</p>
  
  <pre><code>    &lt;FilterParameters&gt;
      &lt;asp:ControlParameter ControlID="DDL" Name="Field1" 
                            PropertyName="SelectedValue" 
                            Type="Int32" /&gt;
      &lt;asp:ControlParameter ControlID="SearchBox" Name="Field2"  
                            Type="String" /&gt;
      &lt;/FilterParameters&gt;
  
  &lt;SelectParameters&gt;
       &lt;asp:ControlParameter ControlID="DDL" Name="Field1" PropertyName="SelectedValue" Type="Int32" /&gt;  
       &lt;asp:ControlParameter ControlID="SearchBox" Name="Field2" Type="String" DefaultValue="" /&gt;  
  &lt;/SelectParameters&gt;
  </code></pre>
  
  <p>Any help would be greatly appreciated!</p>