Pass a string as a variable name QTP

Ideas:

• Use ExecuteGlobal to execute the assignment you want to execute -- if that´s what you want. Eval and especially Execute have subtle limitations regarding the scope they live in.

• The target variable (i.e. the variable that receives a value in the assignment that is evaluated by ExecuteGlobal) must be a global variable.

• If the ExecuteGlobal call happens on an Action's global scope, the target variable must be declared there, too. (I think.)

• If the ExecuteGlobal call happens in a routine in a function library, the target variable must be declared there, too. (I know that for sure. But read on.)

To further help you, I'd need an update on your question because it is not clear what you want to accomplish, and what problems you see. Because -- Eval does not change values, it just evaluates an expression supplied as a string, and returns its value. If the expression has side-effects, like setting a global variable, then you might be out of luck because...well...it depends on where that global variable is declared, and initialized (if at all), and where the ExecuteGlobal call happens. Actions and libraries do NOT share one global scope, even if it looks like they do, and that can create a lot of strange behavior.

But as I said, if you clarify what you are trying to accomplish (got 90% of that), how you attempt to do it (got 40% of it), and what problems you face (got 10% of it), I´m sure I can update this answer so it approaches a solution.

** Update **

I use this library code for all runtime expression evaluation, be it from within a library or Action:

' Interpret (execute) a piece of VSH source code consisting of statements -- success?
'   Code: String containing VBS source code. Passed by reference for performance reasons only
Public Function ExecCode (ByRef Code)
    Dim ErrNumber
    Dim ErrDescription

    On error resume next ' Avoid getting kicked out by errors in the code contained in Code
    ExecuteGlobal Code
    ErrNumber=Err.Number
    ErrDescription=Err.Description
    On error goto 0 ' Re-enable RTE handling

    If ErrNumber <> 0 Then
        ExecCode=false

        Print "Code execution failed ('" & ErrDescription & "'), code:" & vbNewline & Code & "<eof>"
    else
        ExecCode=true
    End If
End Function

Dim GlobalVar

' Interpret (execute) a piece of VSH source code consisting of a single expression -- success?
'   Expr; String containing a VBS expression. Passed by reference for performance reasons only.
'   Target: Variable receiving the value to which the expression evaluates
Public Function EvalCodeAndAssign (ByRef Expr, ByRef Target)

    ' In order to force "Option explicit", we don´t use Eval, but ExecCode (and thus ExecuteGlobal):
    Dim Code: Code="Option Explicit: GlobalVar=(" & Expr & ")"
    Dim Result: Result=ExecCode (Code)
    If Result Then
        Target=GlobalVar
    End If
    EvalCodeAndAssign=Result

End Function

Update 2: if the statement that you pass to ExecuteGlobal contains quotes (which I think are missing in your code), the must be quoted, I.e. you must use double-quotes, like in

ExecuteGlobal "x=""This is a string"""

Because what ExecuteGlobal/Execute/Eval do is: take a string and interpret it as VBScript code. The code you are trying to use is not valid due to missing quotes.