Holder.connectValidateChange

gulong connectValidateChange(T)(T callback,  Flag!"After" after =  No.After) if (isCallable!T
    &&  is(ReturnType!T ==  glib.error.ErrorWrap)
   && (Parameters!T.length <  1 || (ParameterStorageClassTuple!T[0]  ==  ParameterStorageClass.none &&  is(Parameters!T[0]  ==  gobject.value.Value)))
   && (Parameters!T.length <  2 || (ParameterStorageClassTuple!T[1]  ==  ParameterStorageClass.none &&  is(Parameters!T[1] :  gda.holder.Holder)))
   &&  Parameters!T.length <  3)

Connect to ValidateChange signal.

Gets emitted when holder is going to change its value. One can connect to this signal to control which values holder can have (for example to implement some business rules)

Parameters

`callback`	signal callback delegate or function to connect `glib.error.ErrorWrap callback(gobject.value.Value newValue, gda.holder.Holder holder)` `newValue` the proposed new value for holder (optional) `holder` the instance the signal is connected to (optional) `Returns` NULL if holder is allowed to change its value to new_value, or a #GError otherwise.
`after`	Yes.After to execute callback after default handler, No.After to execute before (default)

Returns

Signal ID