检查Hashtable在C#中是否包含特定键
要检查Hashtable是否包含特定键，代码如下-
示例
using System;
using System.Collections;
public class Demo {
public static void Main(){
Hashtable hash = new Hashtable();
hash.Add("One", "Katie");
hash.Add("Two", "John");
hash.Add("Three", "Barry");
hash.Add("Four", "");
hash.Add("Five","Harry");
hash.Add("Six", "F");
hash.Add("Seven", "Tom");
hash.Add("Eight","Andy");
hash.Add("Nine", "I");
hash.Add("Ten", "Tim");
Console.WriteLine("Hashtable Key and Value pairs...");
foreach(DictionaryEntry entry in hash){
Console.WriteLine("{0} and {1} ", entry.Key, entry.Value);
}
Console.WriteLine("Is the Hashtable having fixed size? = "+hash.IsFixedSize);
Console.WriteLine("If Hashtable read-only? = "+hash.IsReadOnly);
Hashtable hash2 = Hashtable.Synchronized(hash);
Console.WriteLine("Is Hash synchronized = "+hash2.IsSynchronized);
Console.WriteLine("Does Hashtable contains the key Ten = "+hash.Contains("Ten"));
}
}输出结果
这将产生以下输出-
Hashtable Key and Value pairs... One and Katie Ten and Tim Five and Harry Three and Barry Seven and Tom Two and John Four and Eight and Andy Nine and I Six and F Is the Hashtable having fixed size? = False If Hashtable read-only? = False Is Hash synchronized = True Does Hashtable contains the key Ten = True
示例
现在让我们来看另一个示例-
using System;
using System.Collections;
public class Demo {
public static void Main(){
Hashtable hash = new Hashtable();
hash.Add("1", "AB");
hash.Add("2", "BC");
hash.Add("3", "DE");
hash.Add("4", "EF");
hash.Add("5", "GH");
hash.Add("6", "IJ");
hash.Add("7", "KL");
hash.Add("8", "MN");
hash.Add("9", "OP");
hash.Add("10", "QR");
Console.WriteLine("Value at key 3 = "+hash["3"]);
Console.WriteLine("Does Hashtable contains the key 12 = "+hash.Contains("12"));
}
}输出结果
这将产生以下输出-
Value at key 3 = DE Does Hashtable contains the key 12 = False