I have a NumericUpDown widget on my winform declared as numEnemyDefence. I want to use this to perform basic math on a variable:
damagePerHit -= Double.Parse(numEnemyDefence.Value);
Where damagePerHit is a double.
However, I am returned with the error of:
Cannot convert decimal to string.
Where is the string coming from? And why is the parse not working?
Double.Parse expects its argument to be a string. NumericUpDown.Value is a decimal. The C# compiler rejects your code because it doesn't make automatic conversions for you from the decimal type to the string type. And this is a good thing because it prevents a lot of subtle errors.
You can simply cast the decimal value to a double value
damagePerHit -= (double)numEnemyDefence.Value;
I also recommend to change (if possible) your variable damagePerHit to a simple decimal if you don't need the precision of a double value.
By the way these kind of operations are also source for other head scratching when you hit the floating point inaccuracy problem