Creating a Property

[qassim]

Hello,
Can any one tell me how to create
and what it the beneift of creating
property with easy example

Bye

[Joacim Andersson]

You create properties by writing property procedurs. These a two different procedures for one property.
The first procedure is for assigning values. It's called a Property Let procedure (or a Property Set procedure if the property actually is an object like Font or Picture).
The second procedure is for retrieving values and is called Property Get procedure.
Here's a simple example:

'local variable to store the property value
Private m_sFirstName As String

Public Property Let FirstName(sNewValue As String)
    'store the new value in the local variable
    m_sFirstName = sNewValue
End Property

Public Property Get FirstName() As String
    'return the stored value
    FirstName = m_sFirstName
End Property

As you can see the Property Let procedure is like a sub that takes an argument (the new value) while the Property Get procedure is like a function that returns the stored value.

You can always argue that this could just as well been a public variable that stored the first name.
Well consider that you might want to check if the value is valid before assigning it.
Maybe you just want to convert the FirstName into proper case. You can't do that with a public variable because you can't tell when it's assign a new value. But with a property procedure you can.

Public Property Let FirstName(sNewValue As String)
    'Check the new value so it's not an empty string
    If Len(sNewValue) > 0 Then
        'convert the value to proper case and then
        'store it in the local variable
        m_sFirstName = StrConv(sNewValue, vbProperCase)
    End If
End Property

You can also make a property read only simply by only writing a Property Get procedure and leave the Property Let procedure out.
This can't be done by using a public variable.

Best regards