Question

I’m using ASP.NET Webforms. I’m creating functionality to filter products based on their attributes.

The way I’m doing it now is taking too long. I need a better, quicker way.

My current method is the following. I have a GridView, which displays Attribute Names. A CheckBoxList is nested in the ItemTemplate which contains the Attribute Values. The CheckBoxList has autopostback=”true”. On each selectedindexchanged event, I loop through the checkboxes and filter based on the checked state. I then compare the filtered results and the checkbox values and disable the checkboxes which aren’t in the filtered results.

Here’s the code which does that:

protected void cblAttr_SelectedIndexChanged(object sender, EventArgs e)
{
    var filteredResults = ProductAttribute.Get(Convert.ToInt32(Request.QueryString["idsite"]));
    var selectedAttributes = filteredResults;

    foreach (GridViewRow row in gridAttrSet.Rows)
    {
        foreach (ListItem item in ((CheckBoxList)row.FindControl("cblAttr")).Items)
        {
            if (item.Selected == true)
            {
                // filter
                selectedAttributes = selectedAttributes.Where(a => a.idAttr == Convert.ToInt32(item.Value)).ToList();
            }
        }
    }

    // this will now contain 
    filteredResults = (from c in filteredResults
                       join o in selectedAttributes
           on c.idProduct equals o.idProduct
                select new ProductAttribute
                {
                    idProduct = c.idProduct,
                    idAttrSet = c.idAttrSet,
                    idAttr = c.idAttr,
                }).ToList();


    foreach (GridViewRow row in gridAttrSet.Rows)
    {
        if (row.RowIndex > ((GridViewRow)((CheckBoxList)sender).NamingContainer).RowIndex)
        {
            foreach (ListItem item in ((CheckBoxList)row.FindControl("cblAttr")).Items)
            {
                // disable if filtered out
                item.Enabled = !(filteredResults.Where(a => a.idAttr == Convert.ToInt32(item.Value)).ToList().Count == 0);
            }
        }
    } 
}

As you can see, there’s alot of looping going on, and there can thousands of records.

What would be a faster way to do this? Any ideas would be appreciated.

Thank you!

Answer 1

The part that was taking time here was the call to the database.