Getting Task Modified By - sharepoint

Question

I'm trying to retrieve a name of the persdon who completed a task. In my Tasks list i can see 'Modified By' which is Editor.
In Sharepoint Manager I can see the persons name in the Editor column.
How can I get this value in the code
I create a task and after the ontaskchanged I have a code block. I've tried many permutations but cannot retrieve this data.

Answer 1

private void UpdateCreatedByAndModifiedByFieldData(string strSiteUrl, string strListName, string strUserFieldName)
{
try
{
SPSecurity.RunWithElevatedPrivileges(delegate()
{
using (SPSite site = new SPSite(strSiteUrl))
{
using (SPWeb web = site.OpenWeb())
{
SPList list = web.Lists[strListName];
foreach (SPListItem listItem in list.Items)
{
//Read user id from a list column of user type and create SPUser object
SPUser user = web.EnsureUser(listItem[strUserFieldName].ToString().Trim());
if (user != null)
{
string userValue = user.ID + ";#" + user.Name;
//Assign the above user to the "Created By" column
listItem["Author"] = userValue;
//Assign the above user to the "Modified By" column
listItem["Editor"] = userValue;
//Call the update method to apply the above changes
listItem.Update();
web.Update();
}
}
}
}
});
}
catch (Exception ex)
{
throw ex;
}
}
Check this also
How to get SharePoint file creator name using AllDocs table?