Probably another beginner's question.

For some reason, I can't even code something simple in a button Click event. When double-clicking on the button, I get the code:

public void btnAceptar_Click(object sender, System.EventArgs e)
{
}

But even when inserting a simple variable declaration within the brackets, I get lots of errors:

public void btnAceptar_Click(object sender, System.EventArgs e)
{
private double CostoUnitario;
}

The first error says that a "}" was expected.

Commenting this line, everything compiles fine - so I don't think it is an issue of mismatched brackets, for example.

Any ideas, what can be wrong?