String.GetEnumerator 方法

定义

检索一个可以循环访问此字符串中的每个字符的对象。Retrieves an object that can iterate through the individual characters in this string.

public:
 CharEnumerator ^ GetEnumerator();
public CharEnumerator GetEnumerator ();
member this.GetEnumerator : unit -> CharEnumerator
Public Function GetEnumerator () As CharEnumerator

返回

枚举器对象。An enumerator object.

示例

下面的示例将循环访问多个字符串中的字符,并显示有关其各个字符的信息。The following example iterates the characters in several strings and displays information about their individual characters. 它使用语言迭代构造,而不是调用 GetEnumerator 方法。It uses the language iteration construct rather than a call to the GetEnumerator method.

using namespace System;

void EnumerateAndDisplay(String^ phrase)
{
   Console::WriteLine("The characters in the string \"{0}\" are:", 
                      phrase);

   int CharCount = 0;
   int controlChars = 0;
   int alphanumeric = 0;
   int punctuation = 0;

   for each (Char ch in phrase) {
      Console::Write("'{0}' ", (! Char::IsControl(ch)) ? ch.ToString() : 
                                "0x" + Convert::ToUInt16(ch).ToString("X4"));
      if (Char::IsLetterOrDigit(ch)) 
         alphanumeric++;
      else if (Char::IsControl(ch)) 
         controlChars++;
      else if (Char::IsPunctuation(ch)) 
         punctuation++;             
      CharCount++;
   }

   Console::WriteLine("\n   Total characters:        {0,3}", CharCount);
   Console::WriteLine("   Alphanumeric characters: {0,3}", alphanumeric);
   Console::WriteLine("   Punctuation characters:  {0,3}", punctuation);
   Console::WriteLine("   Control Characters:      {0,3}\n", controlChars);
}

int main()
{
   EnumerateAndDisplay("Test Case");
   EnumerateAndDisplay("This is a sentence.");
   EnumerateAndDisplay("Has\ttwo\ttabs");
   EnumerateAndDisplay("Two\nnew\nlines");
}
// The example displays the following output:
//    The characters in the string "Test Case" are:
//    'T' 'e' 's' 't' ' ' 'C' 'a' 's' 'e'
//       Total characters:          9
//       Alphanumeric characters:   8
//       Punctuation characters:    0
//       Control Characters:        0
//    
//    The characters in the string "This is a sentence." are:
//    'T' 'h' 'i' 's' ' ' 'i' 's' ' ' 'a' ' ' 's' 'e' 'n' 't' 'e' 'n' 'c' 'e' '.'
//       Total characters:         19
//       Alphanumeric characters:  15
//       Punctuation characters:    1
//       Control Characters:        0
//    
//    The characters in the string "Has       two     tabs" are:
//    'H' 'a' 's' '0x0009' 't' 'w' 'o' '0x0009' 't' 'a' 'b' 's'
//       Total characters:         12
//       Alphanumeric characters:  10
//       Punctuation characters:    0
//       Control Characters:        2
//    
//    The characters in the string "Two
//    new
//    lines" are:
//    'T' 'w' 'o' '0x000A' 'n' 'e' 'w' '0x000A' 'l' 'i' 'n' 'e' 's'
//       Total characters:         13
//       Alphanumeric characters:  11
//       Punctuation characters:    0
//       Control Characters:        2
using System;

class Example
{
   public static void Main() 
   {
      EnumerateAndDisplay("Test Case");
      EnumerateAndDisplay("This is a sentence.");
      EnumerateAndDisplay("Has\ttwo\ttabs" );
      EnumerateAndDisplay("Two\nnew\nlines");
   }

   static void EnumerateAndDisplay(String phrase)
   {
      Console.WriteLine("The characters in the string \"{0}\" are:",
                        phrase);

      int CharCount = 0;
      int controlChars = 0;
      int alphanumeric = 0;
      int punctuation = 0;

      foreach (var ch in phrase) {
         Console.Write("'{0}' ", ! Char.IsControl(ch) ? ch.ToString() : 
                                     "0x" + Convert.ToUInt16(ch).ToString("X4"));
         if (Char.IsLetterOrDigit(ch)) 
            alphanumeric++;
         else if (Char.IsControl(ch)) 
            controlChars++;
         else if (Char.IsPunctuation(ch)) 
            punctuation++;             
         CharCount++;
      }

      Console.WriteLine("\n   Total characters:        {0,3}", CharCount);
      Console.WriteLine("   Alphanumeric characters: {0,3}", alphanumeric);
      Console.WriteLine("   Punctuation characters:  {0,3}", punctuation);
      Console.WriteLine("   Control Characters:      {0,3}\n", controlChars);
   }
}
// The example displays the following output:
//    The characters in the string "Test Case" are:
//    'T' 'e' 's' 't' ' ' 'C' 'a' 's' 'e'
//       Total characters:          9
//       Alphanumeric characters:   8
//       Punctuation characters:    0
//       Control Characters:        0
//    
//    The characters in the string "This is a sentence." are:
//    'T' 'h' 'i' 's' ' ' 'i' 's' ' ' 'a' ' ' 's' 'e' 'n' 't' 'e' 'n' 'c' 'e' '.'
//       Total characters:         19
//       Alphanumeric characters:  15
//       Punctuation characters:    1
//       Control Characters:        0
//    
//    The characters in the string "Has       two     tabs" are:
//    'H' 'a' 's' '0x0009' 't' 'w' 'o' '0x0009' 't' 'a' 'b' 's'
//       Total characters:         12
//       Alphanumeric characters:  10
//       Punctuation characters:    0
//       Control Characters:        2
//    
//    The characters in the string "Two
//    new
//    lines" are:
//    'T' 'w' 'o' '0x000A' 'n' 'e' 'w' '0x000A' 'l' 'i' 'n' 'e' 's'
//       Total characters:         13
//       Alphanumeric characters:  11
//       Punctuation characters:    0
//       Control Characters:        2
Module Example
   Sub Main()
      EnumerateAndDisplay("Test Case")
      EnumerateAndDisplay("This is a sentence.")
      EnumerateAndDisplay("Has" & vbTab & "two" & vbTab & "tabs")
      EnumerateAndDisplay("Two" & vbLf & "new" & vbLf & "lines")
   End Sub 
       
   Sub EnumerateAndDisplay(phrase As String)
      Console.WriteLine("The characters in the string ""{0}"" are:", phrase)
       
      Dim charCount As Integer = 0
      Dim controlChars As Integer = 0
      Dim alphanumeric As Integer = 0
      Dim punctuation As Integer = 0
        
      For Each ch In phrase          
         Console.Write("'{0}' ", If(Not Char.IsControl(ch), ch, 
                                     "0x" + Convert.ToUInt16(ch).ToString("X4")))
         If Char.IsLetterOrDigit(ch) Then 
            alphanumeric += 1
         Else If Char.IsControl(ch) Then 
            controlChars += 1
         Else If Char.IsPunctuation(ch) Then 
            punctuation += 1             
         End If
         CharCount += 1
      Next

      Console.WriteLine()
      Console.WriteLine("   Total characters:        {0,3}", CharCount)
      Console.WriteLine("   Alphanumeric characters: {0,3}", alphanumeric)
      Console.WriteLine("   Punctuation characters:  {0,3}", punctuation)
      Console.WriteLine("   Control Characters:      {0,3}", controlChars)
      Console.WriteLine()
    End Sub 
End Module 
' This example displays the following output:
'    The characters in the string "Test Case" are:
'    'T' 'e' 's' 't' ' ' 'C' 'a' 's' 'e'
'       Total characters:          9
'       Alphanumeric characters:   8
'       Punctuation characters:    0
'       Control Characters:        0
'    
'    The characters in the string "This is a sentence." are:
'       'T' 'h' 'i' 's' ' ' 'i' 's' ' ' 'a' ' ' 's' 'e' 'n' 't' 'e' 'n' 'c' 'e' '.'
'          Total characters:         19
'          Alphanumeric characters:  15
'          Punctuation characters:    1
'          Control Characters:        0
'       
'       The characters in the string "Has       two     tabs" are:
'       'H' 'a' 's' '0x0009' 't' 'w' 'o' '0x0009' 't' 'a' 'b' 's'
'          Total characters:         12
'          Alphanumeric characters:  10
'          Punctuation characters:    0
'          Control Characters:        2
'       
'       The characters in the string "Two
'       new
'       lines" are:
'       'T' 'w' 'o' '0x000A' 'n' 'e' 'w' '0x000A' 'l' 'i' 'n' 'e' 's'
'          Total characters:         13
'          Alphanumeric characters:  11
'          Punctuation characters:    0
'          Control Characters:        2

注解

提示

不是调用 GetEnumerator 方法来检索用于枚举字符串的 CharEnumerator 对象,而应改为使用语言的迭代构造(在中C#,在C++/clr 中,在 Visual Basic 中)。Rather than calling the GetEnumerator method to retrieve a CharEnumerator object that you then use to enumerate a string, you should instead use your language's iteration construct (in C#, in C++/CLR, and in Visual Basic). C#中的foreach适用于C++/clr 中的每个,以及每个在 Visual Basic 中的。foreach in C#, for each in C++/CLR, and For Each in Visual Basic).

此方法使您可以循环访问字符串中的单个字符。This method enables you to iterate the individual characters in a string. 例如,Visual Basic For Each 和C#foreach语句调用此方法以返回一个CharEnumerator对象,该对象可提供对此字符串实例中字符的只读访问。For example, the Visual Basic For Each and C# foreach statements invoke this method to return a CharEnumerator object that can provide read-only access to the characters in this string instance.

适用于

另请参阅