error CS1501: No overload for method 'Base' takes '0' arguments

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One situation that people may get into where the compiler error message may be confusing to them is when the default constructor (ctor) doesn't compile for a class.  Since Whidbey has a bit of a confusing error message for this case (we have a bug for Orcas for it), I wanted to post it on the blog just so someone trying to do a search might hit upon this page.

class Base { public Base(string foo) { } }

class Derived : Base

{

}

Program.cs(3,7): error CS1501: No overload for method 'Base' takes '0' arguments

Program.cs(1,21): (Related location)

As many of you know, in the absence of any specified ctor, the default no-args one is created, so the above source is logically equivalent to:

class Base { public Base(string foo) { } }

class Derived : Base

{

    Derived() : base() { } // implicit by the compiler

}

Once you realize that, the error becomes more clear - that call to base() is trying to call the no-args ctor of the Base class, which does not exist.

The fix depends on your situation, but you'll most likely either add a new no-args ctor to Base or add a non-default ctor to Derived, which I do here:

class Base { public Base(string foo) { } }

class Derived : Base

{

    Derived(string foo) : base(foo) { }

}

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