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StrComp Function (Visual Basic)

Returns -1, 0, or 1, based on the result of a string comparison.

Public Shared Function StrComp( _
   ByVal String1 As String, _
   ByVal String2 As String, _
   <Microsoft.VisualBasic.OptionCompareAttribute> _
   Optional ByVal Compare As Microsoft.VisualBasic.CompareMethod _
) As Integer

String1

Required. Any valid String expression.

String2

Required. Any valid String expression.

Compare

Optional. Specifies the type of string comparison. If Compare is omitted, the Option Compare setting determines the type of comparison.

The Compare argument settings are:

Constant

Description

Binary

Performs a binary comparison, based on a sort order derived from the internal binary representations of the characters.

Text

Performs a text comparison, based on a case-insensitive text sort order determined by your application's current culture information.

The StrComp function has the following return values.

If

StrComp returns

String1 sorts ahead of String2

-1

String1 is equal to String2

0

String1 sorts after String2

1

Exception type

Error number

Condition

ArgumentException

5

Compare value is not valid.

See the "Error number" column if you are upgrading Visual Basic 6.0 applications that use unstructured error handling. (You can compare the error number against the Number Property (Err Object).) However, when possible, you should consider replacing such error control with Structured Exception Handling Overview for Visual Basic.

The strings are compared by alphanumeric sort values beginning with the first character. For further information on binary comparisons, textual comparisons, and sort order, see Option Compare Statement.

Security noteSecurity Note:

If your application makes security decisions based on the result of a comparison or case-change operation, then the operation should use the String.Compare method, and pass Ordinal or OrdinalIgnoreCase for the comparisonType argument. For more information, see How Culture Affects Strings in Visual Basic.

This example uses the StrComp function to return the results of a string comparison. If the third argument is omitted, the comparison type defined in the Option Compare statement or project defaults is performed.

' Defines variables. 
Dim TestStr1 As String = "ABCD" 
Dim TestStr2 As String = "abcd" 
Dim TestComp As Integer 
' The two strings sort equally. Returns 0.
TestComp = StrComp(TestStr1, TestStr2, CompareMethod.Text)
' TestStr1 sorts after TestStr2. Returns -1.
TestComp = StrComp(TestStr1, TestStr2, CompareMethod.Binary)
' TestStr2 sorts before TestStr1. Returns 1.
TestComp = StrComp(TestStr2, TestStr1)

Namespace: Microsoft.VisualBasic

Module: Strings

Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)

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