Question

I want to do this:

public void MyMethod<T>(T myArg) where T: DataTable, String
{
    ...
}

Is this possible?

Answer 1

It would be infinitely preferable to make it two separate methods.

public void MyMethod(DataTable myArg)
{
    ...
}

public void MyMethod(String myArg)
{
    ...
}

or, if generic (I’m not sure why generic is needed in this case)

public void MyMethod<T>(T myArg) where T: DataTable
{
    ...
}

public void MyMethodStr<T>(T myArg) where T: string
{
    ...
}

or worse case, throw errors if not one of those types. That is least preferable as it will throw at runtime not compile.

public void MyMethod<T>(T myArg)
{
    if(myArg is String == false && myString is DataTable == false)
        throw new InvalidArgumentException(...);
}

But besides that, no.