C#

public bool getOperatorResult<T>(string operatorType, T operandA, T operandB)
        {
            //If the operands are boolean values.
            if (typeof(T) == typeof(bool))
            {
                System.Object obj = operandA;
                bool a = (bool) obj;
                obj = operandB;
                bool b = (bool) obj;
                switch (operatorType)
                {
                    case "or":
                        return (a || b);
                    case "and":
                        return (a && b);
                    case "equal":
                        return (a == b);
                    case "notequal":
                        return (a != b);
                    default:
                        return false;
                }
            }
            //If the operands are number values.
            else if ((typeof(T) == typeof(int)) || (typeof(T) == typeof(double)))
            {
                //Do something similar but for both int and double
            }
        }

switch (operatorType)
                {
                    case "lessthan":
                        return (operandA < operandB);
                    case "morethan":
                        return (operandA > operandB);
                    case "lessthanequalto":
                        return (operandA <= operandB);
                    case "morethanequalto":
                        return (operandA >= operandB);
                    case "equal":
                        return (operandA == operandB);
                    case "notequal":
                        return (operandA != operandB);
                    default:
                        return false;
                }

/* DAT_CAPABILITY. Used by application to get/set capability from/in a data source. */
typedef struct {
   TW_UINT16  Cap; /* id of capability to set or get, e.g. CAP_BRIGHTNESS */
   TW_UINT16  ConType; /* TWON_ONEVALUE, _RANGE, _ENUMERATION or _ARRAY   */
   TW_HANDLE  hContainer; /* Handle to container of type Dat              */
} TW_CAPABILITY, FAR * pTW_CAPABILITY;

[StructLayout(LayoutKind.Sequential, Pack = 2)]
internal class TwCapability
{									
    public TwCapability(TwCap cap) // TW_CAPABILITY
    {
        Cap = (short)cap;
        ConType = -1;
        //hContainer = IntPtr.Zero;
    }
    ~TwCapability()
    {
        if (hContainer != IntPtr.Zero)
            Twain.GlobalFree(hContainer);
    }
    public short Cap;
    public short ConType;
    public IntPtr hContainer;
}

public void GetCapabilities()
{
    TwRC rc;
    TwCapability twCap = new TwCapability(TwCap.XferCount); //all sources must support this cap
    rc = DScap(appid, srcds, TwDG.Control, TwDAT.Capability, TwMSG.Get, twCap);
    if (rc == TwRC.Success)
    {
        MessageBox.Show("worked!");
    }
    else MessageBox.Show("not!");
}

[DllImport("twain_32.dll", EntryPoint = "#1")]
private static extern TwRC DScap([In, Out] TwIdentity origin, [In] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, [In, Out] TwCapability capa);

string[] = fileList;
...
do backgroundwork
...
fileList = e.Result;

using ( class1 c1 = new class1() )
{
   //Do something
}

class1 c1 = new class1()
try
{
    //do something
}
finally
{
     c1.Dispose();
}