How to update list Collection value with Index?

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Hi,
I am creating a list variable with my Structure to add dynamically values.

List<emp> empList = new List<emp>();
 emp em = new emp { 
                ecode=textBox1.Text,
                ename=textBox2.Text
            };
            empList.Add(em);

After adding the values I want to change the value whose index is 3(or it's depends on user).
so I am trying this:

empList[listBox1.SelectedIndices[0]].ename = textBox3.Text;

but this line gives error:

Cannot modify the return value of 'System.Collections.Generic.List<NewTech.emp>.this[int]' because it is not a variable

I am searched on google but cannot find the proper result on this..

So my question is :
how to change the List object value with index in C#?

Thanks in advanced..

Regards
Jayanta.

Posted 12-Aug-14 3:15am

JayantaChatterjee

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johannesnestler · Accepted Answer · 2014-08-12T03:32:00

Solution 1

Hi - Simple answer:

Don't use a struct when not appropiate - use a reference type - so your emp struct should be a class if you want to change the values like this.
Rule of Thumb: Never use structs (or read the longer explaination with the same conclusion http://msdn.microsoft.com/en-us/library/ms173109.aspx[^]

OT: Btw emp is not a very good type name - type names should be written uppercase, no abbreviations etc. - I think it's a good idea to go for "common" standards, though personal ones are better than nothing... http://msdn.microsoft.com/en-us/library/ms229042.aspx[^]

Kind regards,

Johannes

Posted 12-Aug-14 3:32am

johannesnestler

Comments

JayantaChatterjee 12-Aug-14 10:09am

Thank you it's worked..
but I am using Struc instead of class because of performance(the collection can be upto 50 or more items).
is there any other way to do this???

johannesnestler 12-Aug-14 10:27am

50? don't even think about a struct - it holds strings so size will be more than 16 bytes for shure... (so no performance benefit) Other way? - of course you can assign a new struct each time you want to change the list "entry" - but you don't want to do that. So in your case change it to a class - it was wrong to define a struct in the first place (http://msdn.microsoft.com/en-us/library/ms229017.aspx)

JayantaChatterjee 12-Aug-14 10:32am

Thank you Sir, I appreciate Your suggestion..

Its help me lots.. :-)

johannesnestler 12-Aug-14 10:46am

you are welcome - good luck with your Projects!