Null Character Truncates String in Visual Basic

Last reviewed: June 5, 1997
Article ID: Q112772

1.00 WINDOWS kbprg kbcode

The information in this article applies to:

Microsoft Visual Basic Programming System, Applications Edition, version 1.0
Microsoft Excel for Windows, version 5.0

SUMMARY

In a Visual Basic procedure, if you use a string that contains the null value in either the SendKeys statement, the MsgBox function, or the Format function, the string is truncated at the null character.

NOTE: This situation is true for both the Microsoft Excel 5.0 for Windows SendKeys statement (using Application.SendKeys) and the Visual Basic, Applications Edition, SendKeys (using just SendKeys) statement.

MORE INFORMATION

The SendKeys statement sends keystrokes to the active windows as if they were typed on the keyboard. Attempting to send a null character causes the string being sent to be truncated at the location of the null character.

You can use the MsgBox function to display a string expression as a message. However, if you use a string expression that contains the null character in the MsgBox function, the characters in the string after the null character do not display in the message box.

The Format function allows you to return an expression such as a string in a named or user-defined format. If you use the Format function in the Debug window to format a string expression that contains the null character, and if the null character is the first character in the string, the value 0 is returned.

Steps to Reproduce Behavior

The following Visual Basic procedure uses the SendKeys statement to send the word "Testing" to the active window:

   Sub Testing()
      SendKeys "Testing"
   End Sub

If you add a null character before the word Testing, the word "Testing" is not sent to the active window. In the following procedure, the keystrokes are not sent to the active window.

   Sub Testing()
      SendKeys Chr(0) + "Testing"
   End Sub

If a null character is placed between two (or more) concatenated strings, the string is truncated at the null character. In the following example, the word "Testing" is sent to the active window, but the string "One, Two, Three" is not.

   Sub Testing()
      SendKeys "Testing" + Chr(0)+ "One, Two, Three"
   End Sub

Microsoft provides examples of Visual Basic procedures for illustration only, without warranty either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose. This Visual Basic procedure is provided 'as is' and Microsoft does not guarantee that it can be used in all situations. Microsoft does not support modifications of this procedure to suit customer requirements for a particular purpose. Note that a line that is preceded by an apostrophe introduces a comment in the code--comments are provided to explain what the code is doing at a particular point in the procedure. Note also that an underscore character (_) indicates that code continues from one line to the next. You can type lines that contain this character as one logical line or you can divide the lines of code and include the line- continuation character. For more information about Visual Basic for Applications programming style, see the "Programming Style in This Manual" section in the "Document Conventions" section of the "Visual Basic User's Guide."

REFERENCES

For more information about the Format Function, choose the Search button in the Visual Basic Reference and type:

   Format

For more information about the Chr Function, choose the Search button in the Visual Basic Reference and type:

Chr

Additional reference words: 5.00 Nul Chr$ vbappcode empty
Keywords : kbcode kbprg
Version : 1.00
Platform : WINDOWS

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Last reviewed: June 5, 1997
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