String.Contains String.Contains String.Contains String.Contains Method

定义

重载

Contains(String, StringComparison) Contains(String, StringComparison) Contains(String, StringComparison) Contains(String, StringComparison)
Contains(Char) Contains(Char) Contains(Char) Contains(Char)
Contains(String) Contains(String) Contains(String) Contains(String)

返回一个值,该值指示指定的子串是否出现在此字符串中。Returns a value indicating whether a specified substring occurs within this string.

Contains(Char, StringComparison) Contains(Char, StringComparison) Contains(Char, StringComparison) Contains(Char, StringComparison)

Contains(String, StringComparison) Contains(String, StringComparison) Contains(String, StringComparison) Contains(String, StringComparison)

public:
 bool Contains(System::String ^ value, StringComparison comparisonType);
public bool Contains (string value, StringComparison comparisonType);
member this.Contains : string * StringComparison -> bool
Public Function Contains (value As String, comparisonType As StringComparison) As Boolean

参数

返回

Contains(Char) Contains(Char) Contains(Char) Contains(Char)

public:
 bool Contains(char value);
public bool Contains (char value);
member this.Contains : char -> bool
Public Function Contains (value As Char) As Boolean

参数

value
Char Char Char Char

返回

Contains(String) Contains(String) Contains(String) Contains(String)

返回一个值,该值指示指定的子串是否出现在此字符串中。Returns a value indicating whether a specified substring occurs within this string.

public:
 bool Contains(System::String ^ value);
public bool Contains (string value);
member this.Contains : string -> bool
Public Function Contains (value As String) As Boolean

参数

value
String String String String

要搜寻的字符串。The string to seek.

返回

如果 true 参数出现在此字符串中,或者 value 为空字符串 (""),则为 value;否则为 falsetrue if the value parameter occurs within this string, or if value is the empty string (""); otherwise, false.

异常

示例

下面的示例确定字符串"fox"是否熟悉引起来的子字符串。The following example determines whether the string "fox" is a substring of a familiar quotation. 如果"按照 fox"在字符串中找到,它还显示其起始位置。If "fox" is found in the string, it also displays its starting position.

using namespace System;

int main()
{
   String^ s1 = "The quick brown fox jumps over the lazy dog";
   String^ s2 = "fox";
   bool b = s1->Contains( s2 );
   Console::WriteLine( "Is the string, s2, in the string, s1?: {0}", b );
   if (b) {
      int index = s1->IndexOf(s2);
      if (index >= 0)
         Console::WriteLine("'{0} begins at character position {1}",
                            s2, index + 1);
   }
}
// This example displays the following output:
//    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
//    'fox begins at character position 17
using System;

class Example
{
    public static void Main() 
    {
       string s1 = "The quick brown fox jumps over the lazy dog";
       string s2 = "fox";
       bool b = s1.Contains(s2);
       Console.WriteLine("'{0}' is in the string '{1}': {2}",
                          s2, s1, b);
       if (b) {
          int index = s1.IndexOf(s2);
          if (index >= 0)
             Console.WriteLine("'{0} begins at character position {1}",
                               s2, index + 1);
       }
    }
}
// This example display the following output:
//    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
//    'fox begins at character position 17
Class Example
   Public Shared Sub Main()
      Dim s1 As String = "The quick brown fox jumps over the lazy dog"
      Dim s2 As String = "fox"
      Dim b As Boolean = s1.Contains(s2)
      Console.WriteLine("'{0}' is in the string '{1}': {2}",
                        s2, s1, b)
      If b Then
          Dim index As Integer = s1.IndexOf(s2)
          If index >= 0 Then
             Console.WriteLine("'{0} begins at character position {1}",
                               s2, index + 1)
          End If
       End If
   End Sub
End Class
'
' This example displays the following output:
'    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
'    'fox begins at character position 17

注解

此方法执行序号 (区分大小写和不区分区域性) 比较。This method performs an ordinal (case-sensitive and culture-insensitive) comparison. 搜索此字符串的第一个字符位置开始并持续到最后一个字符位置。The search begins at the first character position of this string and continues through the last character position.

确定字符串是否包含指定的子字符串使用序号比较 (如区分区域性的比较或不区分大小写的序号比较) 以外的内容,可以创建自定义方法。To determine whether a string contains a specified substring by using something other than ordinal comparison (such as culture-sensitive comparison, or ordinal case-insensitive comparison), you can create a custom method. 下面的示例说明了一种方法。The following example illustrates one such approach. 它定义String包括的扩展方法StringComparison参数,并指示时使用指定的窗体的字符串比较的字符串是否包含子字符串。It defines a String extension method that includes a StringComparison parameter and indicates whether a string contains a substring when using the specified form of string comparison.

using System;

public static class StringExtensions
{
   public static bool Contains(this String str, String substring, 
                               StringComparison comp)
   {                            
      if (substring == null)
         throw new ArgumentNullException("substring", 
                                         "substring cannot be null.");
      else if (! Enum.IsDefined(typeof(StringComparison), comp))
         throw new ArgumentException("comp is not a member of StringComparison",
                                     "comp");

      return str.IndexOf(substring, comp) >= 0;                      
   }
}
Imports System.Runtime.CompilerServices

Module StringExtensions
   <Extension()>
   Public Function Contains(str As String, substring As String, 
                            comp As StringComparison) As Boolean
      If substring Is Nothing Then
         Throw New ArgumentNullException("substring", 
                                         "substring cannot be null.")
      Else If Not [Enum].IsDefined(GetType(StringComparison), comp)
         Throw New ArgumentException("comp is not a member of StringComparison",
                                     "comp")
      End If                               
      Return str.IndexOf(substring, comp) >= 0                      
   End Function
End Module

下面的示例然后调用Contains扩展方法,以确定使用序号比较和不区分大小写的序号比较时是否在字符串中找到子字符串。The following example then calls the Contains extension method to determine whether a substring is found in a string when using ordinal comparison and case-insensitive ordinal comparison.

using System;

public class Example
{
   public static void Main()
   {
      String s = "This is a string.";
      String sub1 = "this";
      Console.WriteLine("Does '{0}' contain '{1}'?", s, sub1);
      StringComparison comp = StringComparison.Ordinal;
      Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp));
      
      comp = StringComparison.OrdinalIgnoreCase;
      Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp));
   }
}
// The example displays the following output:
//       Does 'This is a string.' contain 'this'?
//          Ordinal: False
//          OrdinalIgnoreCase: True
Public Module Example
   Public Sub Main
      Dim s As String = "This is a string."
      Dim sub1 As String = "this"
      Console.WriteLine("Does '{0}' contain '{1}'?", s, sub1)
      Dim comp As StringComparison = StringComparison.Ordinal
      Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp))
      
      comp = StringComparison.OrdinalIgnoreCase
      Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp))
   End Sub
End Module
' The example displays the following output:
'       Does 'This is a string.' contain 'this'?
'          Ordinal: False
'          OrdinalIgnoreCase: True

如果您感兴趣子字符串的位置value在当前实例中,可以调用IndexOf方法以获取其第一个匹配项,或您的起始位置可以调用LastIndexOf方法获取的起始位置及其最后一个匹配项。If you are interested in the position of the substring value in the current instance, you can call the IndexOf method to get the starting position of its first occurrence, or you can call the LastIndexOf method to get the starting position of its last occurrence. 该示例包含对的调用IndexOf(String)方法,如果在字符串实例中找到子字符串。The example includes a call to the IndexOf(String) method if a substring is found in a string instance.

另请参阅

Contains(Char, StringComparison) Contains(Char, StringComparison) Contains(Char, StringComparison) Contains(Char, StringComparison)

public:
 bool Contains(char value, StringComparison comparisonType);
public bool Contains (char value, StringComparison comparisonType);
member this.Contains : char * StringComparison -> bool
Public Function Contains (value As Char, comparisonType As StringComparison) As Boolean

参数

value
Char Char Char Char

返回

适用于