Option Compare Statement
Declares the default comparison method to use when comparing string data.
Option Compare { Binary | Text }
Parts
Term |
Definition |
Binary |
Optional. Results in string comparisons based on a sort order derived from the internal binary representations of the characters. This type of comparison is useful especially if the strings can contain characters that are not to be interpreted as text. In this case, you do not want to bias comparisons with alphabetical equivalences, such as case insensitivity. |
Text |
Optional. Results in string comparisons based on a case-insensitive text sort order determined by your system's locale. This type of comparison is useful if your strings contain all text characters, and you want to compare them taking into account alphabetic equivalences such as case insensitivity and closely related letters. For example, you might want to consider A and a to be equal, and Ä and ä to come before B and b. |
Remarks
If used, the Option Compare statement must appear in a file before any other source code statements.
The Option Compare statement specifies the string comparison method (Binary or Text) for a class, module, or structure. If an Option Compare statement is not included, the default text comparison method is Binary.
In Microsoft Windows, sort order is determined by the code page. For more information, see Code Pages.
In the following example, characters in the English/European code page (ANSI 1252) are sorted by using Option Compare Binary, which produces a typical binary sort order.
A < B < E < Z < a < b < e < z < À < Ê < Ø < à < ê < ø
When the same characters in the same code page are sorted by using Option Compare Text, the following text sort order is produced.
(A=a) < (À = à) < (B=b) < (E=e) < (Ê = ê) < (Z=z) < (Ø = ø)
You can also set Option Compare in the Visual Studio integrated development environment (IDE) or on a command line.
Poznámka
Your computer might show different names or locations for some of the Visual Studio user interface elements in the following instructions. The Visual Studio edition that you have and the settings that you use determine these elements. For more information, see Visual Studio Settings.
To set Option Compare in the IDE |
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To set Option Compare on the command line |
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Example
The following example uses the Option Compare statement to set the binary comparison as the default string comparison method.
' Set the string comparison method to Binary ("AAA" < "aaa").
Option Compare Binary
The following example uses the Option Compare statement to set the case-insensitive text sort order as the default string comparison method.
' Set the string comparison method to Text ("AAA" = "aaa").
Option Compare Text
See Also
Reference
Comparison Operators (Visual Basic)