PC Forms: Err Msg: The Type of Data Did Not Match...

• Microsoft Electronic Forms Designer, version 1.0, running with Microsoft Mail for PC Networks, version 3.0 or 3.2

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 and list box

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