Variable '<variablename>' is used before it has been assigned a value
Variable '<variablename>' is used before it has been assigned a value. A null reference exception could result at run time.
An application has at least one possible path through its code that reads a variable before any value is assigned to it.
If a variable has never been assigned a value, it holds the default value for its data type. For a reference data type, that default value is Nothing (Visual Basic). Reading a reference variable that has a value of Nothing can cause a NullReferenceException in some circumstances.
By default, this message is a warning. For more information on hiding warnings or treating warnings as errors, see Configuring Warnings in Visual Basic.
Error ID: BC42104
To correct this error
Check your control flow logic and make sure the variable has a valid value before control passes to any statement that reads it.
One way to guarantee that the variable always has a valid value is to initialize it as part of its declaration. See "Initialization" in Dim Statement (Visual Basic).
See Also
Tasks
Troubleshooting Variables in Visual Basic
Concepts
Value Types and Reference Types
Variable Declaration in Visual Basic