title: The type 'string' must be a non-nullable value type in order to use it as parameter 'T' in the generic type or method 'System.Nullable<T>'
body: <pre><code>public virtual int Fill(DataSetservices.Jobs_detailsDataTable dataTable, 
      global::System.Nullable&lt;global::System.String&gt; fromdate,     
      global::System.Nullable&lt;global::System.DateTime&gt; todate)
  </code></pre>
  
  <p>I wrote above code in <code>dataset.xsd</code> in C#, but it is throwing an error:</p>
  
  <blockquote>
    <p>Error 1<br>
    The type 'string' must be a non-nullable value type in order
    to use it as parameter 'T' in the generic type or method
    'System.Nullable'</p>
  </blockquote>
  
  <p>Suggest me how to use string because i want to use string and nothing else</p>