How can I loop through objects of a class

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Hi,

I have objects of common classes like this

C#

public static CANBusDetails CANBusRedDetails = null;
public static CANBusDetails CANBusYellowDetails = null;
public static CANBusDetails CANBusGreenDetails = null;
public static CANBusDetails CANBusOrangeDetails = null;

I defined CANBusDetails as class. When I am trying to loop through objects of common classes

C#

for (int i = 1; i < CANBusRedDetails.CANBusMsgIDList.Count; i++)

I am getting Nullreference exception

Can anyone help me in solving the problem???

Thanks
John

Posted 3-Jan-14 1:30am

Member 10408451

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Pheonyx 3-Jan-14 9:14am

You have been given solutions to solve the "nullreference" exception, but you are saying they don't work. Are they giving the same error or a different one? How are you defining your class CANBusDetails? You said with regards to Solution 3 that the class does not have a constructor that takes 0 arguments? What constructors have you defined in the class?

dan!sh 3-Jan-14 9:16am

Please show code where you have defined CANBusMsgIDList property/member. Also, the bits where it is assigned any value.

Member 10408451 3-Jan-14 9:38am

ok,thank you for your suggestions
I have arguments in my constructor which I am not passing
Now I solved the problem

3 solutions

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Ankur^\m/ · Answer 1 · 2014-01-03T01:43:00

Solution 3

Because you have initialized the object as null. You will need to use new keyword to initialize the object. And if you have a constructor defined, it will be called and members initialization code, if any, will be executed.

Currently your object points to null and thus you are getting a null reference error.

Posted 3-Jan-14 1:43am

Ankur^\m/

Comments

Member 10408451 3-Jan-14 8:36am

I tried to use new keyword but showing some error like
does not contains a constructor that takes 0 arguments

Ankur^\m/ 3-Jan-14 9:36am

The error message says it all. You have a constructor defined in the class which accepts sone parameter. When u typed new className(), the intellisense must have shown what parameters are required. Try to find the method named CANBusRedDetails in your class and see what parameters it accepts. Pass those while creating the object.
you really need to get the fundamentals clear before you start programming.

Karthik_Mahalingam · Answer 2 · 2014-01-03T01:36:00

Solution 1

hi Try like this..

might be CANBusRedDetails is null, use the following to avoid null reference error

C#

if( CANBusRedDetails.CANBusMsgIDList != null)
       for (int i = 1; i < CANBusRedDetails.CANBusMsgIDList.Count; i++)

Posted 3-Jan-14 1:36am

Karthik_Mahalingam

Updated 3-Jan-14 1:39am

v2

Comments

Member 10408451 3-Jan-14 8:35am

I tried it
this does not solve my problem

Karthik_Mahalingam 3-Jan-14 8:43am

apply break point and find in which line you are getting error ?

Amol_27101982, India · Answer 3 · 2014-01-03T01:41:00

Solution 2

you are getting Nullreference excption because the object is null.

To loop through the object, you can use foreach
foreach (var obj in CANBusRedDetails.CANBusMsgIDList)
{

obj.yourObjectAttributes
...

}

Hope this will help you.

Thanks,
Amol

Posted 3-Jan-14 1:41am

Amol_27101982, India