C# Char.IsSurrogate(String, Int32)用法及代碼示例

此方法用於指示指定字符串中指定位置的字符是否具有代理代碼單元。

用法:

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

參數：

s：這是一個字符串。
index：是在s中求值的字符位置。

返回值：如果s中位置索引處的字符是高替代或低替代，則此方法返回true，否則返回false。

異常：

ArgumentNullException：如果s為null。
ArgumentOutOfRangeException：如果索引小於零或大於最後一個位置inn s。

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

範例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); 
                                
    } 
}

輸出：

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

範例2：對於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); 
                              
    } 
}

輸出：

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

範例3：對於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); 
                                
    } 
}

輸出：

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

參考：

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：本文由純淨天空篩選整理自RohitPrasad3大神的英文原創作品 C# | Char.IsSurrogate(String, Int32) Method。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。