CODEWITHSUNDEEP
c#
Chris N.P.
Chris N.P.

Reputation: 783

Validating List Object Value

List<string> SampleList = new List<string>();
string tmpStr = "MyStringValue";

From this example, how to check the value of the string variable tmpStr if it's already in SampleList?

Upvotes: 1

Views: 87

Answers (2)

JNL
JNL

Reputation: 4703

Any particular reason for using List?

You can use a Set, Set<string> hs = new HashSet<string>(); and it will not allow duplicates.

Set<string> hs = new HashSet<string>();
hs.add("String1");
hs.add("String2");
hs.add("String3");

// Now if you try to add String1 again, it wont add, but return false.
hs.add("String1");

If you do not want duplicates for case insensitive elements use

HashSet<string> hs = new HashSet<string>(StringComparer.OrdinalIgnoreCase);

Hope that helps.

Upvotes: 3

User 12345678
User 12345678

Reputation: 7804

You could use the List<T>.Contains Method

if (SampleList.Contains(tmpStr))
{
    //  list already contains this value
}
else
{
    // the list does not already contain this value
}

If your objective is to prevent your list from containing duplicate elements at all times then you might consider using the HashSet<T> Class which does not allow for duplicate values.

Upvotes: 3

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