Multiple statements in where clause - entity-framework

Question

I have this strange problem. I have a simple search requirements where a user can search a given entitiy (Say customer) based on several search criterias. User may choose to use a criteria or not. The search conditions need to 'AND' all the criteria. So I write code like this (which works)
IQueryable _customer;
_customer = from c in DS.properties
where
(txtCustomerName.Text.Length == 0 || c.name == txtCustomerName.Text)
&& (txtpropcust1.Text.Length == 0 || c.customfield1 == txtpropcust1.Text)
&& (txtpropcust2.Text.Length == 0 || c.customfield2 == txtpropcust2.Text)
&& (txtpropcust3.Text.Length == 0 || c.customfield3 == txtpropcust3.Text)
&& (txtpropcust4.Text.Length == 0 || c.customfield4 == txtpropcust4.Text)
&& (txtpropcust13.Text.Length == 0 || c.customfield13 == txtpropcust13.Text)
select c;
GridView1.DataContext = _customer;
The problem is that if I have 14 where clauses, the EF throws an error- 13 works - 14 does not.
I am using EF+WCF data service in a WPF application. Is there a setting somewhere which limits the number of where clauses?
Thanks

Answer 1

To simplify the resulting query, you could use:
var customers = DS.properties;
if (txtCustomerName.Text.Length > 0)
customers = customers.Where(x => x.name == txtCustomerName.Text);
if (txtpropcust1.Text.Length > 0)
customers = customers.Where(x => x.customfield1 == txtpropcust1.Text);
// etc
_customer = customers;
GridView1.DataContext = _customer;
Note that this will only add SQL where clauses when there's a need for it.