You can use the Assign method to copy strings from a source list to a destination list, overwriting the contents of the destination list. To append strings without overwriting the destination list, use AddStrings. For example,

Memo1.Lines.Assign(ComboBox1.Items);    { overwrites original strings }

Memo1->Lines->Assign(ComboBox1->Item)s;

copies the lines from a combo box into a memo (overwriting the memo), while

Memo1.Lines.AddStrings(ComboBox1.Items);   { appends strings to end }

Memo1->Lines->AddStrings(ComboBox1->Items);

appends the lines from the combo box to the memo. 

When making local copies of a string list, use the Assign method. If you assign one string-list variable to another—

StringList1 := StringList2;

StringList1 = StringList2;

—the original string-list object will be lost, often with unpredictable results.