C# |从 OrderedDictionary

中删除带有指定键的条目

原文:https://www . geesforgeks . org/c-sharp-remove-entry-with-specified-key-from-ordered dictionary/

OrderedDictionary。Remove(Object) 方法用于从 OrderedDictionary 集合中移除具有指定键的条目。

语法:

public void Remove (object key);

在这里， 键 是要移除的条目的键。

异常:

  • NotSupportedException : 如果 OrderedDictionary 集合是只读的。
  • ArgumentNullException : 如果密钥为空。

下面给出了一些例子，以便更好地理解实现:

例 1:

// C# code to remove the entry
// with the specified key from
// the OrderedDictionary
using System;
using System.Collections;
using System.Collections.Specialized;

class GFG {

    // Driver method
    public static void Main()
    {

        // Creating a orderedDictionary named myDict
        OrderedDictionary myDict = new OrderedDictionary();

        // Adding key and value in myDict
        myDict.Add("key1", "value1");
        myDict.Add("key2", "value2");
        myDict.Add("key3", "value3");
        myDict.Add("key4", "value4");
        myDict.Add("key5", "value5");

        // Displaying the number of element initially
        Console.WriteLine("Number of elements are : " 
                                     + myDict.Count);

        // Displaying the elements in myDict
        foreach(DictionaryEntry de in myDict)
            Console.WriteLine(de.Key + " -- " + de.Value);

        // Removing the entry with the specified
        // key from the OrderedDictionary
        myDict.Remove("key2");

        // Displaying the number of element initially
        Console.WriteLine("Number of elements are : " 
                                     + myDict.Count);

        // Displaying the elements in myDict
        foreach(DictionaryEntry de in myDict)
            Console.WriteLine(de.Key + " -- " + de.Value);
    }
}

输出:

Number of elements are : 5
key1 -- value1
key2 -- value2
key3 -- value3
key4 -- value4
key5 -- value5
Number of elements are : 4
key1 -- value1
key3 -- value3
key4 -- value4
key5 -- value5

例 2:

// C# code to remove the entry
// with the specified key from
// the OrderedDictionary
using System;
using System.Collections;
using System.Collections.Specialized;

class GFG {

    // Driver method
    public static void Main()
    {

        // Creating a orderedDictionary named myDict
        OrderedDictionary myDict = new OrderedDictionary();

        // Adding key and value in myDict
        myDict.Add("A", "Apple");
        myDict.Add("B", "Banana");
        myDict.Add("C", "Cat");
        myDict.Add("D", "Dog");

        // Displaying the number of element initially
        Console.WriteLine("Number of elements are : " 
                                     + myDict.Count);

        // Displaying the elements in myDict
        foreach(DictionaryEntry de in myDict)
            Console.WriteLine(de.Key + " -- " + de.Value);

        // Removing the entry with the specified
        // key from the OrderedDictionary
        // This should raise "ArgumentNullException"
        // as the key is null
        myDict.Remove(null);

        // Displaying the number of element initially
        Console.WriteLine("Number of elements are : " 
                                     + myDict.Count);

        // Displaying the elements in myDict
        foreach(DictionaryEntry de in myDict)
            Console.WriteLine(de.Key + " -- " + de.Value);
    }
}

运行时错误:

未处理异常: 系统。ArgumentNullException:值不能为空。 参数名称:键

注:

  • 被移除的条目之后的条目向上移动以占据空出的位置，并且被移动的条目的索引也被更新。
  • 如果 OrderedDictionary 集合不包含具有指定键的条目，OrderedDictionary 将保持不变，并且不会引发异常。

参考:

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