Using StringCollection specified in Application Settings in a LINQ-to-Entities Query

Question

In my application, I have Property Setting which is of type String.Collections.Specialized.StringCollection. It contains a list of customer codes such as MSFT, SOF, IBM etc. I'm trying to use this in a Linq-to-Entities query in the where clause:

var ShippedOrders = dbcontext.Orders
 .Where(s=>(s.Status.Description.Equals("Shipped") && !Properties.Settings.Default.CustomersToExclude.Contains(s.CustomerCode)));

This fails as Contains is not recognized by Linq-to-Entities with a message similar to:

"LINQ-to-Entities does not recognize the method Contains...."

How do I revise the code above to avoid this error?

score 16 · Answer 1 · answered Sep 13 '12 at 16:55

16

A shorter path is

myProperties.Settings.Default.CustomersToExclude.Cast<string>().Contains(blah);

That's a handy trick for any situation where a collection isn't inherently LINQ-aware.

answered Sep 13 '12 at 16:55

Snort Kapp

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BrokenGlass · Accepted Answer · 2012-02-08T17:37:45.070

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Since your question is tagged as C# 4 use a List<string> instead (StringCollection is ancient) and your query should work. Also you should resolve your list reference outside your query:

List<string> customersToExclude = ..
var ShippedOrders = dbcontext.Orders
                             .Where(s=>(s.Status.Description.Equals("Shipped") 
                                    && !customersToExclude.Contains(s.CustomerCode)));

Edit:

Just copy your customers to an array and use that:

var customerstoExclude = new string[Properties.Settings.Default.CustomersToExclude.Count];
myProperties.Settings.Default.CustomersToExclude.CopyTo(customerstoExclude, 0);

edited Feb 08 '12 at 17:37

answered Feb 08 '12 at 17:25

BrokenGlass

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But List is not an option in the Type drop down in Project Properties -> Settings. That is where I get my list to exclude from. – FMFF Feb 08 '12 at 17:32
1

@FMFF: You could just copy to a string array in that case, see update – BrokenGlass Feb 08 '12 at 17:38

score 1 · Answer 3 · edited May 23 '17 at 11:51

1

This is answered in a related question. EF4 apparently supports Contains directly, though, so that'd be my prefered solution... :)

edited May 23 '17 at 11:51

Community

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answered Feb 08 '12 at 17:24

Jacob Proffitt

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Using StringCollection specified in Application Settings in a LINQ-to-Entities Query

3 Answers3