Protecting Parts of a Document
Allow editing only inside designated text fields while locking the rest of the document in TX Text Control ActiveX. The FieldEntered and FieldLeft events toggle a global flag, and the KeyDown and KeyPress handlers nullify keystrokes when the input position falls outside a field.
I just got an interesting call from a customer who wanted to avoid users from changing the content of a document except for the inserted fields. The text fields in TX Text Control ActiveX have properties that would help avoid changes in the field. But how to protect the rest of the document?
We are going to utilize the field events FieldEntered and FieldLeft of TX Text Control ActiveX and a global flag that informs whether the current input position is inside of a field or not.
Then we have to trap the keystrokes in TX Text Control and nullify the KeyCode or KeyAscii parameter in case the input position is outside a marked text field.
Dim CanEdit As Boolean
Private Sub TXTextControl1_FieldEntered(ByVal FieldId As Integer)
CanEdit = True
End Sub
Private Sub TXTextControl1_FieldLeft(ByVal FieldId As Integer)
CanEdit = False
End Sub
Private Sub TXTextControl1_KeyDown(KeyCode As Integer, Shift As Integer)
If CanEdit = True Then Exit Sub
If (Shift = 2 And KeyCode = 86) Then
KeyCode = 0
End If
End Sub
Private Sub TXTextControl1_KeyPress(KeyAscii As Integer)
If CanEdit = True Then Exit Sub
KeyAscii = 0
End SubIt is also possible to change the EditMode to ReadOnly, but the Undo buffer is going to be deleted to save memory as the user is not able to make changes on the document.
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