Create an order form for a collection - http://shopify.com/partners/blog/93657286-4-advanced-shopify-theming-techniques-to-add-to-your-workflow

four-advanced-shopify-theming-techniques-order-form.liquid

{% comment %}
Source: https://gist.github.com/carolineschnapp/9122054
If you are not on a collection page, do define which collection to use in the order form.
Use the following assign statement, replace 'your-collection-handle-here' with your collection handle.
{% assign collection = collections.your-collection-handle-here %}
Use the assign statement outside of this comment block at the top of your template.
{% endcomment %}

{% paginate collection.products by 100 %}
  
{% if collection.products_count > 0 %}
  <div>
    <h1>{% if template contains 'page' %}{{ page.title }}{% else %}{{ collection.title }}{% endif %}</h1>
    <input type="submit" value="Add to the cart" />
  </div>
{% else %}
  <h1>{% if template contains 'page' %}{{ page.title }}{% else %}{{ collection.title }}{% endif %}</h1>
{% endif %}

{% if template contains 'page' and page.content.size > 0 %}
  <div class="rte">
    {{ page.content }}
  </div>  
{% elsif collection.description.size > 0 %}
  <div class="rte">
    {{ collection.description }}
  </div>
{% endif %}

{% if collection.products_count > 0 %}

  <table>
    <tbody>
    {% for product in collection.products %}
      {% if product.available %}
        {% for variant in product.variants %}
          {% if variant.available %}
            <tr class="{% cycle 'pure-table-odd', '' %}">
              <td>
                  <a href="{{ variant.url | collection }}">
                    <img src="{{ variant.image | default: product.featured_image | img_url: 'small' }}" alt="{{ variant.title | escape }}" />
                  </a>
                </td>
                <td>
                  <a href="{{ variant.url | collection }}">
                   {{ product.title }}{% unless variant.title contains 'Default' %} - {{ variant.title }}{% endunless %}{% unless variant.sku == blank %} - {{ variant.sku }}{% endunless %}
                  </a>
                </td>
                <td>
                   {{ variant.price | money }}
                </td>
                <td style="text-align:right;">
                  <input name="updates[{{ variant.id }}]" onfocus="this.select()" class="quantity field" min="0" {% unless variant.inventory_management == blank or variant.inventory_policy == 'continue' %} max="{{ variant.inventory_quantity }}" {% endunless %} type="text" value="0" tabindex="1" />
                </td>
              </tr>
            {% endif %}
          {% endfor %}
        {% endif %}
      {% endfor %}
      </tbody>
    </table>
    
    <div>
      <input type="submit" value="Add to the cart" />
    </div>
  
  {% else %}
    <p>There are no products in this view.</p>
  {% endif %}

{% endpaginate %}

{% if collection.products_count > 0 %}
<script>
jQuery(function($) {
  $('table .quantity:first').focus();
  $('[max]').change(function() {
    var max = parseInt($(this).attr('max'), 10);
    var value = parseInt($(this).val(), 10) || 0;
    if (value > max) { 
      alert('We only have ' + max + ' of this item in stock');
      $(this).val(max); 
    }    
  });
});
</script>
{% endif %}

<style>
  .action-bar { margin: 15px 0; }
  .action-bar.top { margin: 30px 0 0; }
  .action-bar h1 { margin:0; padding: 0; line-height:1 }
  .left { float: left; }
  .right { float: right; }
  .clearfix:before, .clearfix:after { content: ""; display: table; }
  .clearfix:after { clear: both; }
  .clearfix { zoom: 1; }
  /* Additional styles for table */
  table.pure-table { margin: 15px 0; width: 100%; }
  table.pure-table tr td:first-child, table.pure-table tr th:first-child { padding-left: 12px; }
  table.pure-table tr td:last-child, table.pure-table tr th:last-child { padding-right: 12px; }
  table.pure-table img { float:left; padding: 5px 0; }
  table.pure-table td { vertical-align: middle; }
  .quantity { text-align: center; width: 60px !important; margin: 0 !important; }
</style>

Hi! When I use this I get the following error message

Liquid error: Array 'collection.products' is not paginateable.

Would you know how to resolve this issue?