Exam 70-483 topic 1 question 78 discussion

Actual exam question from Microsoft's 70-483

Question #: 78
Topic #: 1

DRAG DROP -
You have the following class:

You need to implement IEquatable. The Equals method must return true if both ID and Name are set to the identical values. Otherwise, the method must return false. Equals must not throw an exception.
What should you do? (Develop the solution by selecting and ordering the required code snippets. You may not need all of the code snippets.)
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Suggested Answer:

by patoyanez at Feb. 1, 2019, 12:19 a.m.

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patoyanez

Highly Voted 6 years, 4 months ago

the real answer is: if (other == null)return false; if (this.ID != other.ID)return false; if (!Object.Equals(this.Name,other.Name))return false; return true;

upvoted 50 times

BurgSharp

4 years, 11 months ago

return true; does the trick!

upvoted 4 times

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Iryna

Highly Voted 5 years, 7 months ago

nope, the real answer is: if (other == null) return false; if (this.ID != other.ID) return false; if (!this.Name.Equals(other.Name)) return false; return true; Object.Equals will compare not strings, but the references

upvoted 7 times

tanujgyan

5 years, 1 month ago

.Equals will throw an an exception if Name is null. Go for object.Equals method

upvoted 6 times

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banshee

Most Recent 5 years, 7 months ago

Well, for me it looks like both answers are correct, because "Equals" always compares values, not references, regardless if we call it on String or on Object. Am I correct?

upvoted 1 times

gaidys

5 years, 6 months ago

But (!this.Name.Equals(other.Name)) return false; can throw exception if Name is null?

upvoted 3 times

natsk8freak

5 years, 5 months ago

nope... According to Microsoft, it returns false. Name is declared as a String which has builtin handling for null values https://docs.microsoft.com/en-us/dotnet/api/system.string.equals?view=netframework-4.8

upvoted 2 times

ilCorvo

5 years, 4 months ago

I just performed a test and using Equals on a null string throws exception.

upvoted 10 times

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VladWork

5 years, 1 month ago

If this.Name is null you will receive NRE

upvoted 5 times

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