SSIS package : Store value of for loop variable in an array

You can store the value of a for loop variable in an array. Doing this is a little messy IMO. There's likely a cleaner approach using "out of the box" SSIS functionality as @billinkc suggested. However, here are some pointers ...

Let's go with your scenario where you have a for each loop that iterates over some files (using a Foreach File Enumerator) and you want to store the folder names in an array.

Here are some variables we'll use:

FolderList will be the array and CurrentFile will be the for loop variable. The package in its simplest form might look like this:

In the script task, the code might look like this. I've chosen to use a List<string> as my array type, but you could use something else, such as ArrayList. (Note: you'll need to add using statements for System.Collections.Generic and System.IO for the code below):

public void Main()
{
    //get current directory
    string directory = Path.GetDirectoryName(Dts.Variables["User::CurrentFile"].Value.ToString());
    List<string> lst = new List<string>();

    // if the FolderList is already a List<string> then set set it to lst
    if ((Dts.Variables["User::FolderList"].Value is List<string>))
    {
        lst = (List<string>)Dts.Variables["User::FolderList"].Value;
    }           

    // if the directory isn't in the list yet, then add it to the list
    if(!lst.Contains(directory))
    {
        lst.Add(directory);
    }

    // update our variable with the List<string>
    Dts.Variables["User::FolderList"].Value = lst;

    Dts.TaskResult = (int)ScriptResults.Success;
}

Each time the Script Task is executed, you'll get a new folder added to the array. Once the for each loop is done, you may want to examine the values of the array. You can do this using a Script Task (similar to what we did above):

List<string> lst = (List<string>)Dts.Variables["User::FolderList"].Value;
// do stuff with lst

You can also iterate over the values in the array using a for each loop (use the Foreach From Variable Enumerator), which I just learned as I was walking through this (thanks!). Just set the variable to enumerate over to your array variable (here FolderList) and specify another variable (e.g. CurrentFolder) as index 0 in Variable Mappings. This worked for a List<string>, but I'm not sure what other collection types it would work with.