Task.Run with Input Parameters and Output

问题

This works great:

private void MainMethod()
{
    Task<bool> taskItemFound = new Task<bool>(ItemFound);
}

private bool ItemFound()
{
    //Do Work
    return true;
}

This works but is UGLY and I can't pass more than one parameter:

private void MainMethod()
{
    var startNew = Task<bool>.Factory.StartNew(TempMethod, "cow");
}

private bool TempMethod(object o)
{
    return ("holy " + o == "holy cow");
}

I'm looking for a solution that will give me a Task<bool> from an existing method with more than one input parameter and that returns a bool. Ideally, it would look like this:

Task<bool> taskItemFound = new Task<bool>(ItemFound(param1, param2, param3));

回答1:

You can do:

bool result = await Task.Run(() => ItemFound(param1, param2, param3) );

Or if you really want it as Task<bool>:

Task<bool> t = new Task<bool>(() => ItemFound(param1, param2, param3) );

回答2:

Actually, a more clear way would be passing the parameters inside an object. Below you can find solutions to easily achieve that.

Solution 1 (long but clear): Pass an object which holds the parameters

Just create a class which holds the parameters:

class CustomParams
{
   public int Param1 { get; set; }
   public int Param2 { get; set; }
   public int Param3 { get; set; }
}

Then in the method just to cast the object to the class

private bool TempMethod(object arguments)
{
    var args = arguments as CustomParams;
    // Do anything with args.Param1
    // Do anything with args.Param2
    // Do anything with args.Param3
    // Return anything
    return ("holy " + args.Param1 == "holy cow");
}

And to call, use this:

Task<bool> taskItemFound = new Task<bool>(TempMethod, new CustomParams {
    Param1 = 3,
    Param2 = 5,
    Param3 = 2
});

Solution 2 (hacky but shorter): Use Tuples as parameters

This can be used in case you don't want to create a class

Modify the method to cast the object to tuple:

private bool TempMethod(object arguments)
{
    var args = arguments as Tuple<int,int,int>;
    // Do anything with args.Item1
    // Do anything with args.Item2
    // Do anything with args.Item3
    // Return anything
    return ("holy " + args.Item1 == "holy cow");
}

Then use:

Task<bool> taskItemFound = new Task<bool>(ItemFound, new Tuple<int, int>(3,5,7));

Solution 3 (super-hacky, and short): Use dynamic objects

Modify the method to accept dynamic instead of object:

private bool TempMethod(dynamic arguments)
{
    // Do anything with args.Param1
    // Do anything with args.Param2
    // Do anything with args.Param3
    // Return anything
    return ("holy " + arguments.Param1 == "holy cow");
}

And then call using this:

Task<bool> taskItemFound = new Task<bool>(TempMethod, new {Param1 = 3, Param2 = 44, Param3 = 564 });

来源：https://stackoverflow.com/questions/49587439/task-run-with-input-parameters-and-output

标签

task

task-parallel-library