LINQ Query in DataTable

Question

I have a DataTable named dt. It has two Columns named atype_code and module. Now i need to query a module based on specific atype_code.

Here is the code i wrote but not working.

DataTable dt = GetATypeCodeList(); var accType = (from myAccType in dt.AsEnumerable() where myAccType.Field<string>("atype_code") == aTypeCode.Trim() select myAccType.Field<string>("module"));

acctype is a System.Data.EnumerableRowCollection<System.String>.

accType is showing {System.Data.EnumerableRowCollection<object>}how can i get the string out of it??? Thanks — user1227467
– user1227467, Commented Jun 27, 2012 at 10:21

Tim Schmelter · Accepted Answer · 2012-06-27 10:34:37Z

Since you've said that you

need to query a module based on specific atype_code

, i assume that you want only one module with the given atype_code.

Then you should either use Single/SingleOrDefault or First/FirstOrDefault.

String firstModule = dt.AsEnumerable() .Where(r => r.Field<string>("atype_code") == aTypeCode.Trim()) .Select(r => r.Field<string>("module")) .FirstOrDefault(); // or String singleModule = dt.AsEnumerable() .Where(r => r.Field<string>("atype_code") == aTypeCode.Trim()) .Select(r => r.Field<string>("module")) .SingleOrDefault();

Enumerable.Single throws an exception if there is more than one matching element. That can be useful to validate the data.

Edit:

Here's the query-syntax:

IEnumerable<String> modules = from myAccType in dt.AsEnumerable() where myAccType.Field<string>("atype_code") == aTypeCode.Trim() select myAccType.Field<string>("module"); String module = modules.FirstOrDefault(); // returns null if no matching modules were found

Showing errors in Cannot convert type 'System.Data.DataRow' to 'String'

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