title: Got an error "Not supportedException was unhandled by user code"
body: <p>I have  table </p>
  
  <pre><code>  product(table name)
          product_id
          product_name 
          product_image
          product_price
          product_description
          category_id
  
    category(table name )
          category_id
          category_name 
          category_description
  </code></pre>
  
  <p>I have a combobox named it as <code>categoryCombobox</code> and grid view named it as <code>productgridview</code></p>
  
  <p>am trying to populate the datagrid depending upon the selection in the combobox.. like this ....</p>
  
  <pre><code>       private viod form_load(object sender, EventArgs e)
         {
          var products = from prods in abc.products
                         select new
                         {
                             prods.product_Id,
                             productname =  prods.product_Name,
                             productimage = prods.product_Image,
                             productprice = prods.product_Price,
                             productdescription = prods.product_Description
  
                         };
          productbindingsource.DataSource = products;
          productgridview.DataSource = productbindingsource;
          productgridview.Columns[0].Visible = false;
         }
         private void categoryCombobox_SelectedIndexChanged(object sender, EventArgs e)
         {
  
            // is this query correct 
            var categoryid = from productcategories in abc.categories
                           where productcategories.category_Name.Equals(categoryCombobox.Text)
                           select productcategories.category_Id;
  
            var produc = from pros in abc.products
                         where pros.Category_Id.Equals(categoryid)
                         select new
                         {
                             productname = pros.product_Name,
                             productimage = pros.product_Image,
                             productprice = pros.product_Price,
                             productdescription = pros.product_Description                                   
  
                         };
          productbindingsource.DataSource = produc;
          productgridview.DataSource = productbindingsource;
          productgridview.Columns[0].Visible = false;
  
      }      
  </code></pre>
  
  <p>Got an error like this ......</p>
  
  <p>ERROR : At this line    productbindingsource.DataSource = produc;</p>
  
  <blockquote>
    <p>Not supportedException  was unhaldled by user code<br>
    Cannot compare elements of type 'System.Linq.IQueryable`1'.
    Only primitive types (such as Int32, String, and Guid) and entity
    types are supported.</p>
  </blockquote>