Error Handling in VBA

I am working on a procedure to retrieve values from a workbook and insert them into an active worksheet.  I want to do a little data validation on the way, by trapping errors returned by this line.  

returnsExternalData = CDbl(varReturnValue)

If varReturnValue is not a number, I want to return 0.  I am lost on how to trap that condition.
Aaron GreeneProgrammerAsked:
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NorieAnalyst Assistant Commented:
Try this,
If IsNumeric(varReturnValue) Then [u][/u]
    returnsExternalData = CDbl(varReturnValue)
    returnsExternalData = 0
End If

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or this.
returnsExternalData = Val(varReturnValue)

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Note, the second code might not return a double.

You can do this:
returnsExternalData = CDbl(Val(varReturnValue))

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Aaron GreeneProgrammerAuthor Commented:
Thank you.
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