Array.Find无法正常工作

Question

Help me out here, I must be doing something wrong,

The first example here works fine

 DatabaseType = Array.Find(pArgs, Function(s As String) s.ToLower.Contains("/db:")).Replace("/db:", "") 

but if that was false and my variable turned out to be nothing then it throws and object ref exception, so as a result I wrapped an IF around it, but then it never returns true, and also it doesnt populate the variable, like the one below:

 If DatabaseType = Array.Find(pArgs, Function(s As String) s.ToLower.Contains("/db:")).Replace("/db:", "") Then LogAndTrace("Database Type", DatabaseType)

What I need to do is :

Basically I have a num of commandlines arguments I am getting and I need to distiguish what they are each according to their prefix and assign them to the right property , but they are not always going to be there so I wanted to first see if it exist then replace the prefix with nothing, assign it to the property and write it to the log.

Answer 1

It's a bad idea to try to perform assignment within the condition of an If statement. I suspect you want something like this:

Dim databaseType = Array.Find(pArgs, Function(s As String) s.ToLower.Contains("/db:"))
If databaseType IsNot Nothing Then
    databaseType = databaseType.Replace("/db:", "")
    LogAndTrace("Database Type", databaseType)
End If

(That's using a local variable... if you want to assign a property , I'd do that within the If block, when you've performed the replacement.)