DOCUMENT:Q103962  16-NOV-1999  [pcmail]
TITLE   :PC Forms: Err Msg: The Type of Data Did Not Match...
PRODUCT :Microsoft Mail For PC Networks
PROD/VER:WINDOWS:1.0,3.0,3.2
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft Electronic Forms Designer, version 1.0, used with:
    - Microsoft Mail for PC Networks, versions 3.0, 3.2 
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SYMPTOMS
========

When you try to read a message from a form that was created using version 1.0 of
the Microsoft Electronic Forms Designer, the following error message may be
displayed:

   The type of the data did not match the type requested

CAUSE
=====

Two possible causes of this error are:

 - Controls with the same Tag property have different data types.

 - Multiple controls on the Compose/Read form have the same Tag property
   defined.

RESOLUTION
==========

Be sure to use unique Tag properties.

MORE INFORMATION
================

When a form is sent, the WriteTaggedControls() function is called to
automatically package each of the controls on a form with a non-empty Tag
property. The type of control determines what information is written to the
package. (For a complete list of properties written to the package based on
control type, see page 63 in Chapter 5 of the Microsoft Electronic Forms
Designer "Developer's Guide.")

Similarly, when the form is read, the ReadTaggedControls() function is called to
unpackage the data. This function extracts information from the package and
assigns it to the corresponding Tagged control. If, for example, a control on
the Compose form writes a value to the package but is mapped to a control on the
Read form that expects text, the above error is displayed.

Example
-------

Suppose you design an E-form so that the selection from a list box on the Compose
form is written to a read-only text edit control on the Read form, by trying to
use the same "version" Tag property for both controls. When the form is sent,
the index of the list box selection is written to the package as a Long data
type. When the form is read, the text box with Tag "version" is expecting a
String data type, but instead receives a Long. This generates the error message
above.

To solve the problem of handling unlike data types, you can add additional code
to the WriteMessage() and ReadMessage() functions to package the data manually.
For more information on handling list boxes, query on the following words in the
Microsoft Knowledge Base:

   "MailPCForms" (without the quotation marks) and "list box" (without the
   quotation marks)

The error message described in this article may also occur when multiple controls
have the same Tag property defined. If two controls of different types have the
same Tag property, the ReadMessage() function may try to assign an inappropriate
value to a control on the Read form.

To solve this problem, be sure to use unique Tag properties.


Additional query words: 1.00

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Keywords          :  
Technology        : kbZNotKeyword2 kbMailSearch kbZNotKeyword3
Version           : WINDOWS:1.0,3.0,3.2

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