dts. not working in script transform editor but working in script component

I have few ssis variables. But when I enter Dts.Variables["User::MyIntegerVariable"].Value its throwing an error

Severity Code Description Project File Line Suppression State Error CS0234 The type or namespace name 'Variables' does not exist in the namespace 'Microsoft.SqlServer.Dts' (are you missing an assembly reference?)

The samething is working fine in script task. I have added Microsoft.SqlServer.ManagedDTS as a reference in script transformation editor but still throwing an error.

When i entered 'dts.' am not getting 'variable' value