VB函数格式

http://msdn2.microsoft.com/en-us/library/aa445073(VS.60).aspx

Returns a Variant (String) containing a specified number of characters from a string.

Syntax

Mid(string, start[, length])

The Mid function syntax has these named arguments:

Part Description
string Required. String expression from which characters are returned. If string contains Null, Null is returned.
start Required; Long. Character position in string at which the part to be taken begins. If start is greater than the number of characters in string, Mid returns a zero-length string ("").
length Optional; Variant (Long). Number of characters to return. If omitted or if there are fewer than length characters in the text (including the character at start), all characters from the start position to the end of the string are returned.

Mi