C# Definition:

public enum DtrControl : int
{
    /// <summary>
    /// Disables the DTR line when the device is opened and leaves it disabled.
    /// </summary>
    Disable = 0,

    /// <summary>
    /// Enables the DTR line when the device is opened and leaves it on.
    /// </summary>
    Enable = 1,

    /// <summary>
    /// Enables DTR handshaking. If handshaking is enabled, it is an error for the application to adjust the line by
    /// using the EscapeCommFunction function.
    /// </summary>
    Handshake = 2
}

VB Definition:

Public Enum DtrControl As Integer
    Disable = 0
    Enable = 1
    Handshake = 2
End Enum ' DtrControl

Notes:

None.