VB.NET Language in a Nutshell, Second Edition

Name

Mid Statement

Syntax

Mid(target, start[, length]) = string

target (required; String)

The name of the string variable to be modified

start (required; Long)

The position within stringvar at which the replacement commences

length (optional; Long)

The number of characters in stringvar to replace

string (required; String)

The string used to replace characters within stringvar

Description

Replaces a section of a string with characters from another string

Rules at a Glance

• If you omit length, as many characters of string as can fit into stringvar are used.

• If start + length is greater then the length of stringvar, string is truncated to fit in the same space as stringvar. This means that the length of stringvar is not altered by the Mid statement.

• If start is less than 0, runtime error 5, “Invalid procedure call or argument,” occurs.

Programming Tips and Gotchas

• If string is Nothing, a runtime error occurs.

• VB includes the Replace function, which enhances the functionality of the Mid statement by allowing you to specify the number of times the replacement is carried out in the same string.

• Because it is a statement, this version of Mid does not accept named arguments.

• As a statement, Mid is implemented by the compiler, rather than by the Microsoft.VisualBasic.Strings class.

See Also

Mid Function