Partager via

  • Article

Strings.InStr Method (String, String, CompareMethod)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Returns an integer specifying the start position of the first occurrence of one string within another.

Namespace:  Microsoft.VisualBasic
Assembly:  Microsoft.VisualBasic (in Microsoft.VisualBasic.dll)

Syntax

'Declaration
Public Shared Function InStr ( _
    String1 As String, _
    String2 As String, _
    Compare As CompareMethod _
) As Integer

public static int InStr(
    string String1,
    string String2,
    CompareMethod Compare
)

Parameters

  • String1
    Type: System.String
    Required. String expression being searched.
  • String2
    Type: System.String
    Required. String expression sought.
  • Compare
    Type: Microsoft.VisualBasic.CompareMethod
    Optional. Specifies the type of string comparison. If Compare is omitted, the Option Compare setting determines the type of comparison.

Return Value

Type: System.Int32
If String1 is zero length or Nothing, InStr returns 0. If String2 is zero length or Nothing, InStr returns start. If String2 is not found, InStr returns 0. If String2 is found within String1, InStr returns position where match begins. If Start > String2, InStr returns 0.

Remarks

Typically, the InStr function is used when parsing strings.

The Compare argument settings are:

Constant

Value

Description

Binary

0

Performs a binary comparison

Text

1

Performs a text comparison

Examples

This example uses the InStr function to return the position of the first occurrence of one string within another.

' String to search in.
Dim SearchString As String = "XXpXXpXXPXXP"
' Search for "P".
Dim SearchChar As String = "P"

Dim TestPos As Integer
' A textual comparison starting at position 4. Returns 6.
TestPos = InStr(4, SearchString, SearchChar, CompareMethod.Text)

' A binary comparison starting at position 1. Returns 9.
TestPos = InStr(1, SearchString, SearchChar, CompareMethod.Binary)

' If Option Compare is not set, or set to Binary, return 9.
' If Option Compare is set to Text, returns 3.
TestPos = InStr(SearchString, SearchChar)

' Returns 0.
TestPos = InStr(1, SearchString, "W")

Version Information

Silverlight

Supported in: 5, 4, 3

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.