title: get expression of method in Expression tree
body: <p>i want to create the following query in expression trees:</p>
  
  <pre><code>var test = from datarow in tempResults
             where datarow.Field&lt;String&gt;("ColumnName") == "Column"
             select datarow;
  </code></pre>
  
  <p>How do i create the expression:</p>
  
  <pre><code>datarow.Field&lt;String&gt;("ColumnName")?
  </code></pre>
  
  <p>i tried everything, i even got stuck on getting the MethodInfo of Field for the Expression.Call method.
  Field is an extention Method of DataRowExtentions.</p>
  
  <p>Do i have to use Expression.Call() for this? 
  How do i get the MethodInfo? 
  is there a simplier way to do it ?</p>
  
  <p>i tried : </p>
  
  <blockquote>
    <p>ParameterExpression dataRow = Expression.Parameter(typeof(DataRowExtensions), "dataRow");
                Expression left = Expression.Call(dataRow, typeof(DataRowExtensions).GetMethod("Field"));</p>
  </blockquote>
  
  <p>but it doesn't work.</p>
  
  <hr>
  
  <p>i want to create dynamic filters on the data inside IQueryable tempResults.</p>
  
  <p>The user will check on checkboxes on the GUI that will add 'Where' expressions to the data in tempResults. when the user chooses "Column" i want to present the DataRows where ColumnName = "Column".</p>
  
  <p>that is why i need to create the where expression. but i'm so stuck on the MethodInfo thing. I tried this too:</p>
  
  <pre><code>MethodInfo FieldStringMethodInfo = typeof(DataRowExtensions).GetMethod("Field", BindingFlags.Public | BindingFlags.Static);
  </code></pre>
  
  <p>but it doesn't work too.</p>
  
  <p>Is there other ways to do it ?</p>