Passing a generic List<> in C#

Question

I am going brain dead on this; I have several List' defined, based on specific classes (c1, c2, c3...). I have a method that will process information on these lists. What I want to do is pass in the specific list, but have the method accept the generic list, and then via typeof determine what specific work to do. I know its possible, but I cant seem to get the syntax right on the method side. so, for example:

List<c1> c1var; List<c2> c2var; List<c3> c3var;  some_method(c1var); some_method(c2var); some_method(c3var);  class some_thing some_method(List<> somevar) if typeof(somevar).name = x then esle if typeof(somevar).name = y then.... 

How do I set up the parameter list for the method?

thanks in advance R. Sanders

Answer 1

You need to declare some_method to be generic, as well.

void SomeMethod<T>(List<T> someList) {     if (typeof(T) == typeof(c1))     {          // etc     } } 

Answer 2

Careful with the use of typeof(typ1) == typeof(typ2). That will test to see if the types are equivalent disregarding the type hierarchy.

For example:

typeof(MemoryStream) == typeof(Stream); // evaluates to false new MemoryStream() is Stream; //evalutes to true 

A better way to check to see if an object is of a type is to use the 'is' keyword. An example is below:

public static void RunSnippet() {     List<c1> m1 = new List<c1>();     List<c2> m2 = new List<c2>();     List<c3> m3 = new List<c3>();      MyMeth(m1);     MyMeth(m2);     MyMeth(m3); }  public static void MyMeth<T>(List<T> a) {     if (a is List<c1>)     {         WL("c1");     }     else if (a is List<c2>)     {         WL("c2");     }     else if (a is List<c3>)     {         WL("c3");     } }