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");
    }
}   

Answer 3

在参数部分放入List然后尝试在代码switch(typeof(T){case typeof(int): break;})