Upgrade to version 5

You can skip these sections if you are a new dOPC Client Toolkit user. Please note, the version 5 is NOT complete compatible with older dOPC versions. But normally it is very easy to upgrade to the new version. You have only to do following steps:

General changes from version 4 to 5:

We have renamed the class TdOPCServer to TdOPCDACient
We have renamed the class TdOPCSvr to TdOPCCient
We have changed the property Value of class TdOPCItem from OleVariant to Variant
We have deleted event OnWriteError, you can now use event OnWriteComplete instead.

If you want to upgrade a program developed with a previous 4.x versions of dOPC you have two possibilities:

1. Use dOPCOld unit
If you recompile your program you will normally get a compiler error like this: [dcc32 Fatal Error] Unit1.pas(10): F2613 Unit 'dOPC' not found. Please rename unit "dOPC" to "dOPCOld" in uses clauses. This normally all you have to do :-) or if you have a TdOPCServer component on your main form just delete "dOPC" from the unit clause.

2. Rename dOPCServer to dOPCDAClient
This method is not recommended, because it makes a lot of work and it is prone to errors. But on the other hand it is more future proof. If you recompile your program you will normally get a compiler error like this: [dcc32 Fatal Error] Unit1.pas(10): F2613 Unit 'dOPC' not found. 2.1 Delete dOPC unit from unit clause. 2.2 Change the name of your TdOPCServer component e.g. from "OPCServer" to "OPCClient" (the best way is to use the RAD Studio Refactor function) 2.3 Delete the TdOPCServer component from the Mainform (notice the properties and events). 2.4 Add dOPCDAClient component to the main form and assign the properties and events again. 2.5 Rename the component to the same name as the in step 2.2 2.6 Now your program should work as before

2. Rename dOPCServer to dOPCDAClient

This method is not recommended, because it makes a lot of work and it is prone to errors. But on the other hand it is more future proof.

If you recompile your program you will normally get a compiler error like this:
[dcc32 Fatal Error] Unit1.pas(10): F2613 Unit 'dOPC' not found.

2.1 Delete dOPC unit from unit clause.
2.2 Change the name of your TdOPCServer component e.g. from "OPCServer" to "OPCClient"
(the best way is to use the RAD Studio Refactor function)
2.3 Delete the TdOPCServer component from the Mainform (notice the properties and events).
2.4 Add dOPCDAClient component to the main form and assign the properties and events again.
2.5 Rename the component to the same name as the in step 2.2
2.6 Now your program should work as before

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