How Can I Avoid Null Dereference Into .Equals() Method? Can Anyone Help Me Out?

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NxtRecord record = obj as NxtRecord;
if(!this.m_record.Equals(record.m_record))
return false;
else
return true;

Note : m_record is class and record.m_record is struct and I am using VS2008

Posted 10-Oct-15 16:16pm

Member 11770170

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Sergey Alexandrovich Kryukov · Accepted Answer · 2015-10-10T19:31:00

"Null dereference" is absurd. Null is not dereferenced, it's null.

There is one thing you need to understand: as System.Object.Equals can be overridden (https://msdn.microsoft.com/en-us/library/bsc2ak47%28v=vs.110%29.aspx[^]), a really reliable way to compare object with null is using System.Object.ReferenceEquals:
https://msdn.microsoft.com/en-us/library/system.object.referenceequals%28v=vs.110%29.aspx[^].

However, this is usually the issue when you redefine object equivalence for your type and need to use comparison with null in implementation of equality/identity (if you fail to do so, you can face unlimited recursion), or deal with a type which equality is already redefined on some unusual way. In an ordinary situation, simple MyObject == null comparison works just fine.

See also: https://msdn.microsoft.com/en-US/library/ms173147%28v=vs.80%29.aspx[^].

—SA

Bernhard Hiller · Accepted Answer · 2015-10-11T07:14:00

Solution 2

When the other object is null, it is obviously not equal to this object. Consequently, start with

C#

if (record == null)
    return false;

... and make the rest better readable with

C#

else
    return this.m_record.Equals(record.m_record);

Posted 11-Oct-15 7:14am

Bernhard Hiller

Comments

Member 11770170 12-Oct-15 2:36am

Solution 2 is also not working, because am scanning code using HPFortify tool