A friend asked my by e-mail today about a problem he encountered with DotNet interop: how to access a property of an object, if the property name matches a reserved word in NAV. A simplest example is from the Microsoft.Dynamics.Nav.SMTP.SmtpMessage class that comes bundled with NAV 2013.
Consider this piece of code:
Mail := Mail.SmtpMessage;Mail.To := 'john.doe@noname.no';If you try to compile this, it will fail. It’s simple: the To property name is invalid in the C/AL context, because it is a reserved word.
So, how do you fix it?
The answer is: reflection.
Reflection is a built-in functionality into the Framework Class Library that allows you to access meta-information about .NET types, and to dynamically manage that information. I know this is a lousy definition, and all my .NET black-belt ninja friends will now laugh in my face, but I wanted to keep the definition simple for my C/AL friends who don’t have extensive .NET experience.
So, in principle, this is what you must do if you have a situation such as this:
- Get the reference to the type of the object with a stubborn property.
- Use the type reference to get the PropertyInfo class representing the property you are trying to set.
- Use the PropertyInfo instance to dynamically set the value of the property on your object.
Let’s translate it to C/AL now. First, declare a variable of System.Type type from the mscorlib assembly. Then, write this code:
Mail := Mail.SmtpMessage;//Mail.To := 'john.doe@noname.no';Type := GETDOTNETTYPE(Mail);Type.GetProperty('To').SetValue(Mail,'john.doe@noname.no');MESSAGE('%1',Type.GetProperty('To').GetValue(Mail));And that’s it. Try it and see if it works.
You can use the same principle with methods as well. I won’t write any code examples here, because I’ve already posted some examples that showcase this principle. Check the Try..Catch demo from my TechDays 2014 Black Belt session in
this post.
I hope this helps. Please, let me know!
Read this post at its original location at
http://vjeko.com/blog/dotnet-quick-t...-invalid-names, or visit the original blog at
http://vjeko.com. 5e33c5f6cb90c441bd1f23d5b9eeca34
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