Cannot get SSIS Script Task to work

Question

I feel like I am missing some configuration or something, because I have followed tons of tutorials online, but cannot get any examples of a script task to work. I cannot debug the error either because I am not a C# developer.

Currently, I am simply checking if a file exists in a directory:

1) User::gvLastMonthImportFile is string (read-only) & User::gvLastMonthImportFileExists is Boolean (read-write)

2) Added using System.IO; to my namespaces

3)

string fullPath = Dts.Variables["User::gvLastMonthImportFile"].Value.ToString();
Dts.Variables["User::gvLastMonthImportFileExists"].Value = File.Exists(fullPath);
Dts.TaskResult = (int)ScriptResults.Success;`

ERROR:

at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams) at Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTATaskScriptingEngine.ExecuteScript()

Answer 1

I ran into this recently and it was because I had not added the variables to the script.

You have to explicitly add ReadOnlyVariables/ReadWriteVariables to the script task for it to have any access to them by double-clicking the script task in the designer, selecting 'Script' on the right-hand side of the dialog and then clicking the ReadOnlyVariables/ReadWriteVariables drop down.

I know this reply is late but this caused me a lot of grief and hopefully it helps someone.