title: Why the line is empty
body: <p><strong>Update:</strong></p>
  
  <p><strong>Reason:</strong></p>
  
  <p><em>strokeCollection</em> is the data i got from somewhere.
  then i change it to <em>Path.Data</em> like this:</p>
  
  <pre><code>foreach (var stroke in strokeCollection)
  {
      pathGeometry.AddGeometry(stroke.GetGeometry());
  }
  </code></pre>
  
  <p>Unfortunately, the <em>GetGeometry</em> method will give me a path like <strong><em>1</em></strong>.it is empty.
  In order to ensure stroke have all been included into the path, <em>GetGeometry</em> method is the stroke's border.</p>
  
  <p><strong>Question:</strong></p>
  
  <p>When I set my strokethickness to 1px, the line is empty. like <em>1</em>.</p>
  
  <pre><code> &lt;Path Stroke="Red" StrokeThickness="1" Data="{Binding PathData}" /&gt;
  </code></pre>
  
  <p>and then I binding the line's fill to the stroke. it changed to <em>2</em>.</p>
  
  <pre><code> &lt;Path Stroke="{Binding Stroke}" Fill="{Binding Stroke}" StrokeThickness="1" Data="{Binding PathData}" /&gt;
  </code></pre>
  
  <p>and I think it thickness is 2px.</p>
  
  <p>I change the line thickness to 10px, and stroke to <code>#1AFF0000</code>, it changed to <em>4</em>.</p>
  
  <p><strong>behidecode.cs:</strong></p>
  
  <pre><code>Stroke = new SolidColorBrush("#1AFF0000");
  </code></pre>
  
  <p><strong>xaml:</strong></p>
  
  <pre><code>&lt;Path Stroke="{Binding Stroke}" Fill="{Binding Stroke}" StrokeThickness="10" Data="{Binding PathData}" /&gt;
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/uBm8e.png" alt="enter image description here"></p>
  
  <h2>Questions</h2>
  
  <ol>
  <li><p>How to draw a solid line, the width is 1px? </p></li>
  <li><p>How to clear the darkred in the <em>4</em>?</p></li>
  </ol>