There are a few issues with the formula, including a mixture of using , and ; to separate function arguments, an extra closing parenthesis on the LookUp call, and others. Something similar to the expression below should work:
UpdateContext({ QuantiteAValider: NumberInput1.Value});
With(
{ recordToUpdate: LookUp(Tableau1,'Article'= "GANTS NITRILE PLUS 5540 VERT. 45 CM. EP. 0.56 MM T09 COV.5539") },
Patch(
'Tableau des articles de protection',
recordToUpdate,
{ 'Stock Actuel': recordToUpdate.'Stock actuel' - QuantiteAValider }
)
)
Or below if your language uses ',' as the decimal separator (which would be the case for French):
UpdateContext({ QuantiteAValider: NumberInput1.Value});;
With(
{ recordToUpdate: LookUp(Tableau1;'Article'= "GANTS NITRILE PLUS 5540 VERT. 45 CM. EP. 0.56 MM T09 COV.5539") };
Patch(
'Tableau des articles de protection';
recordToUpdate;
{ 'Stock Actuel': recordToUpdate.'Stock actuel' - QuantiteAValider }
)
)
Hope this helps!