CanApply property

Returns a Boolean value indicating whether or not data on the page can be saved.

Remarks

CanApply is called for each page when changes need to be saved. Only when all pages return True will the ApplyChanges method be called. If any page returns False, the pages will remain in edit mode for the user to correct the problem. This code should never be removed.

Following is the default extension of this method in the form templates:

Private Property Get IAMExtensionPage_CanApply() As Boolean
    On Error GoTo Error_handler
    Dim bDataValid As Boolean
    ' Todo
    ' Add your code here
    bDataValid = True
    
    Me.ValidateControls
    If Not m_Designer Is Nothing Then
        ' Set the edit mode of the datasource
        IAMExtensionPage_CanApply = m_Designer.CanApply(Me) And bDataValid
    End If
    
    Exit Sub
Error_handler:
    MsgBox caption & " CanApply: " & Err.Description
End Property

You can add extra code to check if the data entered by the user is valid, as in the following example.

Example

Private Property Get IAMExtensionPage_CanApply() As Boolean
    On Error GoTo Error_handler
    Dim bDataValid As Boolean
    
    ' Check the information entered by the user
    If txtProjectName.Text = "" Then
            bDataValid = False
            ' Explain why the input is invalid
            MsgBox "You must enter a project name!"
            ' Make sure this page (with the invalid input) is visible
            SwitchToPage m_Designer, Me.caption
            ' Set focus to the field that needs to be corrected
            txtDrawingNumber.SetFocus
    Else
        bDataValid = True
    End If
    
    Me.ValidateControls
    If (Not m_Designer Is Nothing) Then
        IAMExtensionPage_CanApply = m_Designer.CanApply(Me) And bDataValid
    End If
    
    Exit Sub
Error_handler:
    MsgBox caption & " CanApply: " & Err.Description
End Property

' See Name property to define the name of your page
Public Sub SwitchToPage(UIExt As IAMUIExtensionDesigner, Name As String)
    Dim pf As IAMPagesFrame
    Set pf = UIExt.GetHostService(SERVICE_PAGESFRAME)
    If Not pf Is Nothing Then
        pf.CurrentPage = Name
    End If
End Sub

Related information

IAMExtensionPage interface

ApplyChanges method

PageHandlesErrors property