StringDictionary.ContainsValue(String)方法用于检查StringDictionary是否包含特定值。
句法:
public virtual bool ContainsValue (string value);
在这里, value是要在StringDictionary中找到的值。该值可以为空。
返回值:如果StringDictionary包含具有指定值的元素,则该方法返回true ,否则返回false 。
下面的程序说明了StringDictionary.ContainsValue(String)方法的用法:
范例1:
// C# code to check if the
// StringDictionary contains
// a specific value
using System;
using System.Collections;
using System.Collections.Specialized;
class GFG {
// Driver code
public static void Main()
{
// Creating a StringDictionary named myDict
StringDictionary myDict = new StringDictionary();
// Adding key and value into the StringDictionary
myDict.Add("G", "Geeks");
myDict.Add("F", "For");
myDict.Add("C", "C++");
myDict.Add("DS", "Data Structures");
myDict.Add("N", "Noida");
// Checking if "C++" is contained in
// StringDictionary myDict
if (myDict.ContainsValue("C++"))
Console.WriteLine("StringDictionary myDict contains the value");
else
Console.WriteLine("StringDictionary myDict does not contain the value");
}
}
输出:
StringDictionary myDict contains the value
范例2:
// C# code to check if the
// StringDictionary contains
// a specific value
using System;
using System.Collections;
using System.Collections.Specialized;
class GFG {
// Driver code
public static void Main()
{
// Creating a StringDictionary named myDict
StringDictionary myDict = new StringDictionary();
// Adding key and value into the StringDictionary
myDict.Add("G", "Geeks");
myDict.Add("F", "For");
myDict.Add("C", "C++");
myDict.Add("DS", "Data Structures");
myDict.Add("N", "Noida");
// Checking if "null" is contained in
// StringDictionary myDict
// It should not raise any exception
if (myDict.ContainsValue(null))
Console.WriteLine("StringDictionary myDict contains the value");
else
Console.WriteLine("StringDictionary myDict does not contain the value");
}
}
输出:
StringDictionary myDict does not contain the value
笔记:
- 使用Object.Equals方法将StringDictionary的元素值与指定值进行比较。
- 此方法是O(n)运算,其中n是Count。
参考:
- https://docs.microsoft.com/zh-cn/dotnet/api/system.collections.specialized.stringdictionary.containsvalue?view=netframework-4.7.2