title: What is the datatype of this width?
body: <p>I'm trying to define a local resource in my xaml which is supposed to be the width of my cells, so rather than going:</p>
  
  <pre><code>&lt;Setter Property="ColumnStretchMinWidth" Value="75"/&gt;
  &lt;Textbox Width="75" /&gt;
  &lt;ColumnDefinition Width="*" MinWidth="75" /&gt;
  ...etc
  </code></pre>
  
  <p>I can go</p>
  
  <pre><code>&lt;Setter Property="ColumnStretchMinWidth" Value="{StaticResource MinCellWidth}"/&gt;
  &lt;Textbox Width="{StaticResource MinCellWidth}" /&gt;
  &lt;ColumnDefinition Width="*" MinWidth="{StaticResource MinCellWidth}" /&gt;
  </code></pre>
  
  <p>But when I define this constant, I get binding errors saying it can't cast. When I go</p>
  
  <pre><code>&lt;System:String x:Key="MinCellWidth"&gt;"75"&lt;/s:String&gt;
  </code></pre>
  
  <p>I get an error saying it can't convert from String to Double for some controls. When I go</p>
  
  <pre><code>&lt;System:Double x:Key="MinCellWidth"&gt;"75"&lt;/s:Double&gt;
  </code></pre>
  
  <p>I get an error saying it can't convert from Double to string for other controls (like the ColumnDefinition, where "*" widths are allowed).</p>
  
  <p>What is the magic type of the hardcoded <code>="75"</code> that lets it be converted to the appropriate type for each control. How can I define a resource that can be used in all these different places?</p>