Here is how the VFP toolkit for .NET did it:

/// <summary>
/// Receives an expression and a list of values as parameter and returns a true
/// if the expression exists in the list. Please note that the Visual FoxPro's
/// InList() function has a limitation of in items whereas this one does not have
/// a limitation on the number of items passed.
/// </summary>
/// <example>
/// Console.WriteLine(InList("Kamal", "Pat", "abc", "Kamal"));	//returns true
/// Console.WriteLine(InList("Kamal", "Pat", "abc", "xyz"));	//returns false
/// Console.WriteLine(InList(123, 12, 13, 16, 1717, 123));	//returns true
/// </example>
/// <param name="tcExpression"></param>
/// <param name="toVar"></param>
/// <returns></returns>
public static bool InList(object toExpression, params object[] toItems)
{
	return Array.IndexOf(toItems,  toExpression) > -1;
}

>if there any similar vfp inlist() command in C#?
>
>
>for eg.
>
>VFP Code:
>
>IF INLIST(postCode,'001','002','003')
>...
>ENDIF
>
>
>
>Thanks.