Mid Function (Visual Basic)
Returns a string containing a specified number of characters from a string.
Public Shared Function Mid( _ ByVal str As String, _ ByVal Start As Integer, _ Optional ByVal Length As Integer _ ) As String
Required. String expression from which characters are returned.
Required. Integer expression. Starting position of the characters to return. If Start is greater than the number of characters in str, the Mid function returns a zero-length string (""). Start is one based.
Optional. Integer expression. Number of characters to return. If omitted or if there are fewer than Length characters in the text (including the character at position Start), all characters from the start position to the end of the string are returned.
Start <= 0 or Length < 0.
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.
To determine the number of characters in str, use the Len function.
Visual Basic has a Mid function and a Mid statement. These elements both operate on a specified number of characters in a string, but the Mid function returns the characters while the Mid statement replaces the characters. For more information, see Mid Statement.
The MidB function in previous versions of Visual Basic returns a string in bytes rather than characters. It is used primarily for converting strings in double-byte character set (DBCS) applications. All Visual Basic strings are in Unicode, and MidB is no longer supported.
This example uses the Mid function to return a specified number of characters from a string.
' Creates text string. Dim TestString As String = "Mid Function Demo" ' Returns "Mid". Dim FirstWord As String = Mid(TestString, 1, 3) ' Returns "Demo". Dim LastWord As String = Mid(TestString, 14, 4) ' Returns "Function Demo". Dim MidWords As String = Mid(TestString, 5)
Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)