One of the sore points of using Script component is assigning value to variables. Read Write variables can only be altered in Post Execute phase. Script Component runs the code for each record and this would affect performance adversely. For details check "Coding and Debugging the Script Component". In case I need to assign the value of system variable "PackageName" to a readWrite user variable "PkgNm". You could use it in several other ways. Assigning values from Source to a variable for instance.
Here is a sample code to assign value to Read write variable on the post execute phase:
Tags: SSIS, Script Component, Post Execute, SQL Server, MSBI,