I am having what I think might be a common problem.
When upgrading my applications to VB 2005 from VB 2003, I have received a number of warnings regarding my declarations of local Strings without a default value assigned initially.
Example of My earlier code:
Dim tmpDriveType as Strin
Warning treated as error : Variable 'tmpDriveType' is used before it has been assigned a value. A null reference exception could result at runtime.
This is an easy fix by simply declaring the local variable as follows:
Dim tmpDriveType as String = ""
Not a problem, problem solved and understood.
However, I have several code declares as follows:
Example # 1
Dim AllProcess As Process()
AllProcess = Process.GetProcesses
Return AllProcess
Example # 2
Dim AllProcess As Process()AllProcess = Process.GetProcessesByName(strProcessName)
'return array of all process properties for each instance runningReturn AllProcess
Example # 3
Dim logDirectoryProperties As System.IO.DirectoryInfo If My.Computer.FileSystem.DirectoryExists("C:\backup\logs") ThenlogDirectoryProperties =
My.Computer.FileSystem.GetDirectoryInfo("C:\backup\logs") End IfMsgBox(logDirectoryProperties.Exists.ToString)
With these examples I am currently battling, I am getting the same error and I have no clue as to what to default these variable to in order to eliminate the errors.
Any help of direction would be much appreciated.
Variable Declare Error issue VB 2005
AndrewMcK
Thanks, this fixed this problem.
For some reason I was looking or thinking of some default specific variable type on this and overlooked the most obvious Nothing.
Dim tmp Do I feel like an idiot = Yes
PoonamTS
Typically your code is more maintainable when you are explicit in your object instantiation, particularly on Reference types (objects, strings, etc). Value types will have default values where VS will complain if you try to explicitly instantiate them to the default (ex dim foo as boolean = false).
I wanted to take each of your examples and tweak them a bit.
For Example 1, you don't need the AllProcess local variable. You could just do the following:
Return Process.GetProcesses
Example 2 you can shorten as well to
Return Process.GetProcessByName(strProcessName)
Example 3 is a bit trickier. The challenge here is on your last line (MsgBox). In your case, if the directory does not exist, you are asking the message box to display the exists property on an object that was never instantiated. The instantiation happens within the If block but the msgbox is outside of the block. You need to put the MsgBox line inside the If block. Additionally, you may want to add an else clause to notify the user that the directory does not exist, or to create it if necessary.
Jim Wooley
http://devauthority.com/blogs/jwooley
Yash.cse