The error is saying there’s not method getal that has a string parameter.
You’re invoking getal with txtNumber.text (string) as argument and the compiler is looking for a getal method with a string parameter and can’t find it. The existing getal method doesn’t take any parameters.
public int getal(string x)
{
_a += _a;
return _a;
}
Of course you still need to define what you are going to do with the string parameter “x” defined in getal but now it compiles.
solved C# – No overload for method “getal” takes 1 argument