WD98: Error Message Using Mid(), Left() or Right() Function

ID: Q181103

The information in this article applies to:

Microsoft Word 98 Macintosh Edition

SYMPTOMS

When you use the Mid(), Right() or Left() functions, you may receive the following error message:

   Run-time error '5': "Invalid procedure call or argument"

CAUSE

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This problem occurs when the length parameter for the statement is negative.

NOTE: In Word 2.0 for Windows, a negative value in the count parameter of the Mid$(), Right$() or Left$() functions is ignored and does not generate an error.

The Mid() function returns a portion of a text string starting at a given character position. The syntax for the command is

   Mid(<string>, <start> [, <length>])

where <string> is the text string to search, <start> is the character position from which to start, and <length> is the number of characters to return. If no <length> parameter is specified, or if there are fewer than <length> characters in the text, the function returns all the characters from the <start> position to the end of the string.

The following sample macro illustrates the error message described in the "Symptoms" section of this article:

   Sub ErrorOccurs()
      Dim Test As String
      Test = Mid("hello", 1, -1)
      MsgBox Test
   End Sub

The following sample macro returns the error because the length of the string variable Test minus one is a negative number (0 - 1 = -1):

   Sub ErrorOccurs()
      Dim Test As String
      Dim ReturnText As String
      Test = ""
      ' Empty string, could be passed as an empty dialog
      ' variable, for example.
      ReturnText = Mid(Test, Len(Test) - 1)
   End Sub

NOTE: Word version 2.0 for Windows ignores a -1 value for the <length> parameter. So in Word 2.0 all the characters from the first character position to the end of the string are displayed in the message box. In the first example, the string "hello" is displayed.

RESOLUTION

To keep this error from occurring, first test the length of the string. For example:

   Sub ErrorDoesNotOccur()
      Dim Test As String
      Dim ReturnText As String
      ' Empty string, could be passed as an empty dialog
      ' variable, for example.
      Test = ""
      ' Test the length of the string to ensure
      ' that subtracting 1 from the length leaves
      ' at least 1 character.
      If Len(Test) - 1 > 0 then
         ReturnText = Mid(Test, Len(Test) - 1)
      End If
   End Sub

MORE INFORMATION

For more information about the Mid, Right or Left Functions/Statements, click the Office Assistant while in the Visual Basic Editor, type "Returning Strings from Functions," click Search, and then click to view "Returning Strings from Functions."

NOTE: If the Assistant is hidden, click the Office Assistant button on the Standard toolbar. If the Assistant is not able to answer your query, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q176476
   TITLE     : OFF: Office Assistant Not Answering Visual Basic Questions

REFERENCES

For more information about getting help with Visual Basic for Applications, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q163435
   TITLE     : VBA: Programming Resources for Visual Basic for
               Applications

Additional query words: wordcon kbcode kbmacro vba vbe

Keywords          : kbdta kbdtacode kbmacroexample macword98 
Platform          : MACINTOSH
Issue type        : kbprb

Last Reviewed: April 6, 1999