转SSIS 2012 pass values from child package to parent with project deployment model

http://stackoverflow.com/questions/20288766/ssis-2012-pass-values-from-child-package-to-parent-with-project-deployment-model

• Parameter binding on the execute package task is currently a ONE way street Parent --> Child.

• Here is a way to pass a value from a child package variable to a parent package variable.

  Script Task: (in child package)

• // Populate collection of variables.
  // This will include parent package variables.
  Variables vars = null;
  Dts.VariableDispenser.GetVariables(ref vars);
  
  // Lock the to and from variables. 
  Dts.VariableDispenser.LockForWrite("User::MyParentPackageVar");
  Dts.VariableDispenser.LockForRead("User::MyChildPackageVar");
  
  // Apparently need to call GetVariables again after locking them.
  // Not sure why - perhaps to get a clean post-lock set of values.
  Dts.VariableDispenser.GetVariables(ref vars);
  vars["User::MyParentPackageVar"].Value = vars["User::MyChildPackageVar"].Value;
  
  vars.Unlock();
  

  This code was actually from a pre-2012 SSIS Package that I just finished upgrading to SSIS for SQL Server 2012 (in Visual Studio 2012), and converted to project deployment model.

  Initially, the execution died (after a lengthy delay) on the variable assignment line. But then I added the "User::" prefix, which apparently was necessary for at least one, but not all of the variables I was assigning this way. The prefix was not necessary in SSIS for SQL Server 2008.