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This article mainly introduces "what is the content of the C # Dictionary generic collection". In the daily operation, I believe that many people have doubts about the content of the C # Dictionary generic collection. The editor consulted all kinds of materials and sorted out a simple and useful method of operation. I hope it will be helpful for you to answer the question of "what is the content of the C # Dictionary generic collection?" Next, please follow the editor to study!

C # generic collection is the most common use of generics. The namespace System.Collections.Generic contains some generic collection classes. Dictionary generic collection is one of the C # generic collections. Using generic collection classes can provide higher type safety and higher performance, avoiding repeated boxing and unboxing of non-generic collections. Many non-generic collection classes have corresponding generic collection classes, commonly used non-generic collection classes, and corresponding generic collection classes:

C # correspondence between non-generic collection classes of generic collections and generic collection classes:

ArrayList corresponds to List

HashTable corresponds to Dictionary

Queue corresponds to Queue

Stack corresponds to Stack

SortedList corresponds to SortedList

The most common non-generic collection classes we use are ArrayList class and HashTable class. We often use HashTable to store the information to be written to or returned to the database, which requires continuous type conversion, which increases the burden of packing and unpacking the system. It is much more convenient if the data types we manipulate are relatively certain to use Dictionary collection classes to store data, for example, when we need to store users' shopping cart information (product name, corresponding number of items) in e-commerce websites. You can use Dictionary to store shopping cart information without any type conversion.

The following is a simple example of a Dictionary generic collection, including declaring, populating key-value pairs, removing key-value pairs, and traversing key-value pairs

Dictionary < string,string > myDic=newDictionary < string,string > (); myDic.Add ("aaa"); myDic.Add ("bbb", "222"); myDic.Add ("ccc", "333"); myDic.Add ("ddd", "444"); / / if an existing key is added, the add method throws an exception try {myDic.Add ("ddd", "ddd"). } catch (ArgumentExceptionex) at this point, the study on "what is the content of the C # Dictionary generics collection" is over. I hope I can solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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