Unpredictable choice between method overloads when binding to command

[mr146]

Example

XAML part:

...
<Button Command="{Binding MyHandler}" />
...

Code-behind:

...
// [1]
public void MyHandler(string x) {}
// [2]
public void MyHandler() {}
...

Expected behavior: [2] is executed
Actual behavior: [1] is executed

If we will swap methods [1] and [2], then [2] will be executed.

Also, the problem appears when CommandParameter is specified: the expected behavior is that [1] will be executed always, but actually, it depends on the order of methods.

Bonus: CommandParameter="zzz" leads to app termination after button click when the chosen overload receives int parameter.

[grokys]

My feeling here is that handlers should be one of the following signatures:

void Handler();

Or

void Handler(object? o);

The second form with an object parameter should be chosen over the first form if present.

Reasoning: CommandParameter is an object and we don't want to be deciding which overload should be called at runtime: the handler should be decided at compile time. If the user wants to do dynamic dispatch then they would implement void Handler(object? o) and dispatch themselves.