Linq c# Querying based on a Variable

Question

I want to be able to do something like this below where I select the field based on a variable name. The below doesn't work and i cant find a solution without doing a big switch statement.

var guidId = new Guid("");
var fieldName= "somefield";

var query =
 from c in Financials
 where c.GuidId == guidId 
 select **fieldName**;

Is their a simple way to do this?

Thanks Austin

So `**fieldName**` actually is a string which is the name of the property? Dynamic LINQ [> here <](http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx) — Tim Schmelter, Feb 28 '13 at 16:30
@JW. By simple i mean way of doing this without a massive switch.. — Austin, Feb 28 '13 at 16:32

score 2 · Accepted Answer · edited May 23 '17 at 11:57

2

Try this out:

select c.GetType().GetProperty(fieldName).GetValue(c, null)

I found this on this SO question. If my answer doesn't work for some reason in the query you can just select c and then just put it through the method as shown in the answer to the SO question.

Note: It returns an object, so be careful!

edited May 23 '17 at 11:57

Community

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answered Feb 28 '13 at 16:33

Corey Adler

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After quite a bit of trail and error i managed to get the function on the link to work. Do you know if this will have much effect on performance as i have heard reflection is bad? – Austin Mar 01 '13 at 08:50

score 0 · Answer 2 · answered Feb 28 '13 at 16:34

0

You could use reflection:

select c.GetType().GetProperty(fieldName).GetValue(c, null);

It's really the only way to get the value of a property by name.

answered Feb 28 '13 at 16:34

itsme86

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Linq c# Querying based on a Variable

2 Answers2