I have a method
public void method(params object[][] arg)
But where I call the method, I have and object[] and object[][]:
object[] var1 = new object[5];
object[][] var2 = new object[8][5];
method(var1, var2); (I´d like this to be method(var1, var2[0], var2[1], var2[2],...)
But inside method, arg has length 2:
arg[0] = var1
arg[1] = var2
But I want arg as an array of length 9:
arg[0] = var1
arg[1] = var2[0];
arg[2] = var2[1];
...
How can I call the method?
It sounds like you want:
object[][] args = new[] { var1 }.Concat(var2).ToArray();
method(args);
The "normal" parameter array handling of C# doesn't do any flattening: you either call it with a single argument which is already the right type, or you call it with a sequence of arguments of the element type. You can't mix and match.
In general, for methods that accept a params array I also provide an overload that accepts IEnumerable<T>:
public void MyMethod(params string[] args)
{
MyMethod((IEnumerable<string>)args);
}
public void MyMethod(IEnumerable<string> args)
{
// ...
}
Then you can also easily provide an enumerable as the parameter. For example:
string[] var1 = new string[5];
string[][] var2 = new string[8][5];
// Jon Skeet's suggestion without ToArray():
var sequence = new[] { var1 }.Concat(var2);
MyMethod(sequence);
If you really want to use the syntax you propose, you can do that since in your example you use object[]. An array of objects is also an object, therefore you can do the flattening inside your method:
public void MyMethod(params object[] args)
{
object[] flattened = arg
// For each element that is not in an array, put it in an array.
.Select(a => a is object[] ? (object[])a : new object[] { a })
// Select each element from each array.
.SelectMany(a => a)
// Make the resulting sequence into an array.
.ToArray();
// ...
}
MyMethod(var1, var2);
