I have a method which performs some operations on a TADOConnection
object, which sometimes seems to occur when the connection is in a state which would not permit this operation. When this happens, an exception is thrown and processing fails. I want to enclose the method in an if
statement which simply checks the state of the TADOConnection
to ensure it is closed before proceeding.
Therefore, I have the following:
procedure MyClass.OperateOnADOConnection;
begin
if ADOConnection.State = stClosed then
begin
//do my operations
end;
end;
I get a compile time error for this, because State
and stClosed
are apparently not the same object type. I also tried if ADOConnection.State = TObjectStates.stClosed then
but then I got a different error.
Delphi documentation is pretty limited and doesn't really explain how things are used, as far as I can see. I do not have access to a Delphi IDE as I am not usually a Delphi programmer and licenses are limited - so I am using Visual Studio Code. No online tutorials that I have found make mention of the .State
property, either.
How am I supposed to use this property?
The State
property is defined as a Set of TObjectState
values:
A set is a collection of values of the same ordinal type. The values have no inherent order, nor is it meaningful for a value to be included twice in a set.
The State
can hold multiple TObjectState
values at one time. You are trying to compare the entire Set
to a specific value, which is why you are getting errors. You should instead be checking if the desired value is contained within the Set
. You can use the in
operator for that purpose, eg:
//if ADOConnection.State = stClosed then
if stClosed in ADOConnection.State then