CharEnumerator.Current CharEnumerator.Current CharEnumerator.Current CharEnumerator.Current Property

定义

获取由此 CharEnumerator 对象枚举的字符串中当前引用的字符。Gets the currently referenced character in the string enumerated by this CharEnumerator object.

public:
 property char Current { char get(); };
public char Current { get; }
member this.Current : char
Public ReadOnly Property Current As Char

属性值

当前由此 CharEnumerator 对象引用的 Unicode 字符。The Unicode character currently referenced by this CharEnumerator object.

实现

异常

该索引无效;即它位于枚举字符串的第一个字符之前或最后一个字符之后。The index is invalid; that is, it is before the first or after the last character of the enumerated string.

示例

下面的示例使用CharEnumerator类来枚举字符串中的单个字符。The following example uses the CharEnumerator class to enumerate the individual characters in a string. 它通过CharEnumerator MoveNext调用方法来实例化对象, 并通过调用方法从一个字符移动到下一个字符, 并通过检索Current属性的值来显示当前字符。 String.GetEnumeratorIt instantiates a CharEnumerator object by calling the String.GetEnumerator method, moves from one character to the next by calling the MoveNext method, and displays the current character by retrieving the value of the Current property.

String ^ title = "A Tale of Two Cities";
CharEnumerator ^ chEnum = title->GetEnumerator();
int ctr = 1;
String ^ outputLine1 = nullptr;
String ^ outputLine2 = nullptr;
String ^ outputLine3 = nullptr; 

while (chEnum->MoveNext())
{
   outputLine1 += ctr < 10 || ctr % 10 != 0 ? "  " : (ctr / 10) + " ";
   outputLine2 += (ctr % 10) + " ";
   outputLine3 += chEnum->Current + " ";
   ctr++;
}

Console::WriteLine("The length of the string is {0} characters:", 
                  title->Length);
Console::WriteLine(outputLine1);
Console::WriteLine(outputLine2);    
Console::WriteLine(outputLine3);
// The example displays the following output to the console:      
//       The length of the string is 20 characters:
//                         1                   2
//       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
//       A   T a l e   o f   T w o   C i t i e s
string title = "A Tale of Two Cities";
CharEnumerator chEnum = title.GetEnumerator();
int ctr = 1;
string outputLine1 = null;
string outputLine2 = null;
string outputLine3 = null; 

while (chEnum.MoveNext())
{
   outputLine1 += ctr < 10 || ctr % 10 != 0 ? "  " : (ctr / 10) + " ";
   outputLine2 += (ctr % 10) + " ";
   outputLine3 += chEnum.Current + " ";
   ctr++;
}

Console.WriteLine("The length of the string is {0} characters:", 
                  title.Length);
Console.WriteLine(outputLine1);
Console.WriteLine(outputLine2);    
Console.WriteLine(outputLine3);
// The example displays the following output to the console:      
//       The length of the string is 20 characters:
//                         1                   2
//       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
//       A   T a l e   o f   T w o   C i t i e s
Dim title As String = "A Tale of Two Cities"
Dim chEnum As CharEnumerator = title.GetEnumerator()
Dim ctr As Integer = 1
Dim outputLine1, outputLine2, outputLine3 As String 

Do While chEnum.MoveNext()
   outputLine1 += CStr(iif(ctr < 10 Or ctr Mod 10 <> 0, "  ", CStr(ctr \ 10) + " ")) 
   outputLine2 += (ctr Mod 10)& " "
   outputLine3 += chEnum.Current & " "
   ctr += 1
Loop

Console.WriteLine("The length of the string is {0} characters:", _
                  title.Length)
Console.WriteLine(outputLine1)
Console.WriteLine(outputLine2)    
Console.WriteLine(outputLine3)
' The example displays the following output to the console:      
'       The length of the string is 20 characters:
'                         1                   2
'       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
'       A   T a l e   o f   T w o   C i t i e s

但请注意, 可以使用foreach (在中C#) 或For Each (在 Visual Basic 中) 以更直观的方式执行相同的操作, 如下面的示例所示。Note, however, that the same operation can be performed somewhat more intuitively by using foreach (in C#) or For Each (in Visual Basic), as the following example shows.

String ^ title = "A Tale of Two Cities";
int ctr = 1;
String ^ outputLine1 = nullptr;
String ^ outputLine2 = nullptr;
String ^ outputLine3 = nullptr; 

for each (wchar_t ch in title)
{
   outputLine1 += ctr < 10 || ctr % 10 != 0 ? "  " : (ctr / 10) + " ";
   outputLine2 += (ctr % 10) + " ";
   outputLine3 += ch + " ";
   ctr++;
}

Console::WriteLine("The length of the string is {0} characters:", 
                  title->Length);
Console::WriteLine(outputLine1);
Console::WriteLine(outputLine2);    
Console::WriteLine(outputLine3);
// The example displays the following output to the console:      
//       The length of the string is 20 characters:
//                         1                   2
//       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
//       A   T a l e   o f   T w o   C i t i e s
string title = "A Tale of Two Cities";
int ctr = 1;
string outputLine1 = null;
string outputLine2 = null;
string outputLine3 = null; 

foreach (char ch in title)
{
   outputLine1 += ctr < 10 || ctr % 10 != 0 ? "  " : (ctr / 10) + " ";
   outputLine2 += (ctr % 10) + " ";
   outputLine3 += ch + " ";
   ctr++;
}

Console.WriteLine("The length of the string is {0} characters:", 
                  title.Length);
Console.WriteLine(outputLine1);
Console.WriteLine(outputLine2);    
Console.WriteLine(outputLine3);
// The example displays the following output to the console:      
//       The length of the string is 20 characters:
//                         1                   2
//       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
//       A   T a l e   o f   T w o   C i t i e s
Dim title As String = "A Tale of Two Cities"
Dim ctr As Integer = 1
Dim outputLine1, outputLine2, outputLine3 As String 

For Each ch As Char In title
   outputLine1 += CStr(iif(ctr < 10 Or ctr Mod 10 <> 0, "  ", CStr(ctr \ 10) + " ")) 
   outputLine2 += (ctr Mod 10)& " "
   outputLine3 += ch & " "
   ctr += 1
Next

Console.WriteLine("The length of the string is {0} characters:", _
                  title.Length)
Console.WriteLine(outputLine1)
Console.WriteLine(outputLine2)    
Console.WriteLine(outputLine3)
' The example displays the following output to the console:      
'       The length of the string is 20 characters:
'                         1                   2
'       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
'       A   T a l e   o f   T w o   C i t i e s

注解

类维护枚举字符串的内部索引, Current属性返回索引当前引用的字符。 CharEnumeratorThe CharEnumerator class maintains an internal index to the enumerated string, and the Current property returns the character that is currently referenced by the index. 仅当索引有效时才应调用此属性;否则, 将引发异常。This property should be invoked only when the index is valid; otherwise, an exception is thrown.

索引对于空字符串 ("") 始终无效。The index is always invalid for an empty string (""). 调用String.GetEnumeratorReset方法后, 该索引也无效。The index is also invalid after the String.GetEnumerator or Reset method is called. 在调用这些方法中的任一方法后, MoveNext调用方法将索引调整为枚举字符串中的第一个字符。After either of these methods is called, invoke the MoveNext method to adjust the index to the first character in the enumerated string. 只要MoveNext方法返回true, 索引就有效。The index is valid whenever the MoveNext method returns true.

CurrentCurrent调用、 MoveNext Reset或之前,不会移动索引和连续调用来返回相同的字符。String.GetEnumeratorCurrent does not move the index, and consecutive calls to Current return the same character until MoveNext, Reset, or String.GetEnumerator is called.

适用于