How to lock specific rows and columns using Excel interop C#

Question

I am trying to Lock cell range in excel using C# excel interop services but I am unable to do it with following code

sheet.Range["A1", "A3"].Locked = true;

Answer 1

In Excel, you can only effectively lock cells if you lock the worksheet. What you do is:

1. Mark the cell ranges you don't want to lock as Locked = False
2. Then protect the sheet using sheet.Protect(UserInterfaceOnly: true).