Is this a maskedtextbox control?
If it is then you can set the property TextMaskFormat = ExcludePromptAndLiterals and then the value of the Text property will be stripped of the mask characters and the move should work.
You might want to use TryParse instead if you wish to validate that the field contains valid characters.
01 field pic 9(10).
01 numfield decimal.
01 mystring string.
set mystring to maskedtextbox1::Text
if type Decimal::TryParse(mystring, numfield)
move numfield to field
else
invoke type MessageBox::Show("Error not numeric")
end-if