Question

I have a method to which I pass an IEnumerable<TModel>. Then depending on the type of TModel, the method carries out a set of instructions as below:

    public void MyMethod<TModel>(IEnumerable<TModel> items) where TModel : class
    {
        int operationType;
        switch (typeof(TModel))
        {
            case typeof(MyModelOne):
                operationType = 1;
                break;
            case typeof(MyModelTwo):
                operationType = 2;
                break;
            case typeof(MyModelThree):
                operationType = 3;
                break;
            default:
                throw new Exception("The collection model passed to MyMethod is not recognized");
        }
        ...
    }

This doesnt work, I get the error:

There is no application variable or memeber ‘TModel’

Answer 1

You can’t switch on a Type variable. Replace it with cascading if statements.

 if (typeof(TModel) == typeof(MyModelOne)) {
    operationType = 1;
 } else if (typeof(TModel) == typeof(MyModelTwo)) {
    operationType = 2;
 } // ...