trying to determine if a date has changed in a mshflexgrid vb6

[isnoend07]

I have mshlexgrid that has a column of dates if the date is clicked it opens another form with a calendar
if a new date is selected it replaces the selected date
how can i wait to see if a new date has been selected. before continuing
Dim OldDate as string
Dim NewDate as string
OldDate= gridMaster.TextMatrix(mintgridMasterCurRow,mintgridMasterCurCol)
open the calendar
now see it a date has been selected
Have code processing wait to see if a new date has been selected
NewDate= gridMaster.TextMatrix(mintgridMasterCurRow,mintgridMasterCurCol)
If NewDate <> OldDate then
mbGridisDirty = true
Save the grid
else
mbGridisDirty = false
End If
how can this be done?