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String.Substring Method (Int32, Int32)

Retrieves a substring from this instance. The substring starts at a specified character position and has a specified length.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public string Substring(
	int startIndex,
	int length
)

Parameters

startIndex
Type: System.Int32

The zero-based starting character position of a substring in this instance.

length
Type: System.Int32

The number of characters in the substring.

Return Value

Type: System.String
A string that is equivalent to the substring of length length that begins at startIndex in this instance, or Empty if startIndex is equal to the length of this instance and length is zero.

ExceptionCondition
ArgumentOutOfRangeException

startIndex plus length indicates a position not within this instance.

-or-

startIndex or length is less than zero.

startIndex is zero-based.

NoteNote

This method does not modify the value of the current instance. Instead, it returns a new string with length characters starting from the startIndex position in the current string.

The following example uses the Substring method in three cases to isolate substrings within a string. In two cases the substrings are used in comparisons, and in the third case an exception is thrown because invalid parameters are specified.

using System;

public class Sample
{
   public static void Main() {
      String myString = "abc";
      bool test1 = myString.Substring(2, 1).Equals("c"); // This is true.
      Console.WriteLine(test1);
      bool test2 = String.IsNullOrEmpty(myString.Substring(3, 0)); // This is true.
      Console.WriteLine(test2);
      try {
         string str3 = myString.Substring(3, 1); // This throws ArgumentOutOfRangeException.
         Console.WriteLine(str3);
      }
      catch (ArgumentOutOfRangeException e) {
         Console.WriteLine(e.Message);
      }         
   }
}
// The example displays the following output: 
//       True 
//       True 
//       Index and length must refer to a location within the string. 
//       Parameter name: length

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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