Help copying field values within a form

[cshort64]

I want to keep history of a change on one field. I only need to keep the last change.

Example I have two fields CurrentSerialNum and OldSerialNum. If a change is made to CurrentSerialNumb on the form I want to copy the value of CurrentSerialNum (prior to the change) to OldSerialNum.

I have added the following code to onclick and onupdate sections of CurrentSerialNum however on updating the CurrentSerialNum field OldSerialNum is updated to null. Any idea on what I am doing wrong?

Private Sub CurrentSeriealNum_AfterUpdate()
me.OldSerialNum.Value = mCurrentSerialNum
End Sub

Public Sub CurrentSeriealNum_Click()
Dim mCurrentSerialNum As String
mCurrentSerialNum = me.CurrentSeriealNum
End Sub

[Toyman]

I want to keep history of a change on one field. I only need to keep the last change

Example I have two fields CurrentSerialNumber and OldSerialNumber. If a change is made to CurrentSerialNumber on the form I want to copy the value of CurrentSerialNumber prior to the change to OldSerialNumber.

I have added the following code to onclick and onupdate sections of CurrentSerialNum however on updating the CurrentSerialNum field OldSerialNum is updated to null. Any idea on what I am doing wrong.

Private Sub CurrentSeriealNum_AfterUpdate()
me.OldSerialNum.Value = mCurrentSerialNum
End Sub

Public Sub CurrentCalibratorSeal_Click()
Dim mCurrentSerialNum As String
mCurrentSerialNum = Me.CurrentSeriealNum
End Sub

You need to put the code in the "on enter" event:
Dim mCurrentSerialNum As String
mCurrentSerialNum = Me.CurrentSeriealNum

[cshort64]

Thanks Toyman,

I tried that and have the same results. Do I need to pass the variable to the onupdate process?

[Toyman]

Thanks Toyman,

I tried that and have the same results. Do I need to pass the variable to the onupdate process?

make sure your veriable, "mCurrentSerialNum" is decleared for the form and not just the current procedure. To do that, you need to declear it at the top of the vb window, right below "Option Compare Database"