C# Char.IsSurrogate(String, Int32)用法及代码示例

此方法用于指示指定字符串中指定位置的字符是否具有代理代码单元。

用法:

public static bool IsSurrogate (string s, int index);

参数：

s：这是一个字符串。
index：是在s中求值的字符位置。

返回值：如果s中位置索引处的字符是高替代或低替代，则此方法返回true，否则返回false。

异常：

ArgumentNullException：如果s为null。
ArgumentOutOfRangeException：如果索引小于零或大于最后一个位置inn s。

以下示例程序旨在说明Char.IsSurrogate(String，Int32)方法的用法：

范例1：

// C# program to demonstrate 
// Char.IsSurrogate(String, 
// Int32) Method 
using System; 
  
class GFG { 
  
    // Main Method 
    public static void Main() 
    { 
        try { 
  
            // calling check() Method 
            check("1234", 3); 
            check("Tsunami", 3); 
            check("psyc0lo", 4); 
  
            // declaring and initializing string s1 
            string s1 = new String(new char[] {'a', 
                        '\uD800', '\uDC00', 'z' }); 
            check(s1, 2); 
        } 
        catch (ArgumentNullException e) { 
  
            Console.Write("Exception Thrown:"); 
            Console.Write("{0}", e.GetType(), e.Message); 
        } 
        catch (ArgumentOutOfRangeException e) { 
  
            Console.Write("Exception Thrown:"); 
            Console.Write("{0}", e.GetType(), e.Message); 
        } 
    } 
  
    // Defining check() method 
    public static void check(string s, int i) 
    { 
        // checking condition 
        bool val = Char.IsSurrogate(s, i); 
  
        // checking 
        if (val) 
            Console.WriteLine("String '{0}' contains "
               + "Surrogate value at index {1} ",s, i); 
                                
        else
            Console.WriteLine("String '{0}' does't contain any"
                        + "Surrogate value at index {1}",s, i); 
                                
    } 
}

输出：

String '1234' does't contain anySurrogate value at index 3
String 'Tsunami' does't contain anySurrogate value at index 3
String 'psyc0lo' does't contain anySurrogate value at index 4
String 'að??z' contains Surrogate value at index 2

范例2：对于ArgumentNullException

// C# program to demonstrate 
// Char.IsSurrogate(String, 
// Int32) Method 
using System; 
  
class GFG { 
  
    // Main Method 
    public static void Main() 
    { 
        try { 
  
            // calling check() Method 
            check("1234", 3); 
            check("Tsunami", 3); 
            check("psyc0lo", 4); 
  
            // declaring and initializing string s1 
            string s1 = new String(new char[] { 'a', 
                         '\uD800', '\uDC00', 'z' }); 
  
            check(s1, 2); 
  
            Console.WriteLine(""); 
            Console.WriteLine("s is null"); 
            check(null, 4); 
        } 
        catch (ArgumentNullException e) { 
  
            Console.Write("Exception Thrown:"); 
            Console.Write("{0}", e.GetType(), e.Message); 
        } 
        catch (ArgumentOutOfRangeException e) { 
  
            Console.Write("Exception Thrown:"); 
            Console.Write("{0}", e.GetType(), e.Message); 
        } 
    } 
  
    // Defining check() method 
    public static void check(string s, int i) 
    { 
  
        // checking condition 
        bool val = Char.IsSurrogate(s, i); 
  
        // checking 
        if (val) 
            Console.WriteLine("String '{0}' contains "
               + "Surrogate value at index {1} ",s, i); 
                                
        else
            Console.WriteLine("String '{0}' does't contain any"
                       + "Surrogate value at index {1}",  s, i); 
                              
    } 
}

输出：

String '1234' does't contain anySurrogate value at index 3
String 'Tsunami' does't contain anySurrogate value at index 3
String 'psyc0lo' does't contain anySurrogate value at index 4
String 'að??z' contains Surrogate value at index 2 

s is null
Exception Thrown:System.ArgumentNullException

范例3：对于ArgumentOutOfRangeException

// C# program to demonstrate 
// Char.IsSurrogate(String, 
// Int32) Method 
using System; 
  
class GFG { 
  
    // Main Method 
    public static void Main() 
    { 
        try { 
  
            // calling check() Method 
            check("1234", 3); 
            check("Tsunami", 3); 
            check("psyc0lo", 4); 
  
            // declaring and initializing string s1 
            string s1 = new String(new char[] {'a',  
                        '\uD800', '\uDC00', 'z' }); 
            check(s1, 2); 
  
            Console.WriteLine(""); 
            Console.WriteLine("index is less than zero"); 
            check("null", -4); 
        } 
        catch (ArgumentNullException e) { 
  
            Console.Write("Exception Thrown:"); 
            Console.Write("{0}", e.GetType(), e.Message); 
        } 
        catch (ArgumentOutOfRangeException e) { 
  
            Console.Write("Exception Thrown:"); 
            Console.Write("{0}", e.GetType(), e.Message); 
        } 
    } 
  
    // Defining check() method 
    public static void check(string s, int i) 
    { 
  
        // checking condition 
        bool val = Char.IsSurrogate(s, i); 
  
        // checking 
        if (val) 
            Console.WriteLine("String '{0}' contains "
              + "Surrogate value at index {1} ",  s, i); 
                               
        else
            Console.WriteLine("String '{0}' does't contain any"
                       + "Surrogate value at index {1}", s, i); 
                                
    } 
}

输出：

String '1234' does't contain anySurrogate value at index 3
String 'Tsunami' does't contain anySurrogate value at index 3
String 'psyc0lo' does't contain anySurrogate value at index 4
String 'að??z' contains Surrogate value at index 2 

index is less than zero
Exception Thrown:System.ArgumentOutOfRangeException

参考：

https://docs.microsoft.com/en-us/dotnet/api/system.char.issurrogate?view=netframework-4.7.2#System_Char_IsSurrogate_System_String_System_Int32_

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注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 C# | Char.IsSurrogate(String, Int32) Method。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。