Question

I have a GridView with an EntityDataSource.

I want to filter the rows at runtime using QueryExtender, by comparing it with multiple strings.

i.e., return only rows where a certain field is IN (‘string1’, ‘string2′, string3’)

Can someone point me towards an answer? Thanks.

Edit: I already know how to do this for one string, read from a control at runtime. But I’m unable to find anything on Google that demonstrates what I’m trying to achieve.

Answer 1

Having a Enumerable<T> you can define a List<string> containing the list of strings you are looking for and then write something like:

List<string> search = new List<string>();
            search.Add("string 1");
            search.Add("string 2");

            var query = from ex in YourEntities
                    where search.Contains(ex.Field)
                select ex;

query will have the items you are looking for.

UPDATE

I am not familiar with the QueryExtender control but this MSDN tutorial suggests that you do the following:

Add a CustomExpressionFilter between the opening and closing tags of the QueryExtender control:

<asp:CustomExpression OnQuerying="FilterByStrings"></asp:CustomExpression>

And then define in your code such method:

protected void FilterByStrings(object sender, CustomExpressionEventArgs e)
{
     List<string> search = new List<string>();
                search.Add("string 1");
                search.Add("string 2");

     e.Query = from ex in e.Query.Cast<YourEntity>()
               where search.Contains(ex.Field)
               select ex;
}