重写相同逻辑的最佳方法是什么？

Question

if ((ddl1.SelectedValue == "1") || (ddl1.SelectedValue == "100"))
{
    if (Fee > 0)
    { 
        Messages += " [Please the check fee and ddl1 type selected] "; 
    }
}
else if ((ddl1.SelectedValue == "2") || (ddl1.SelectedValue == "200"))
{
    if (Fee == 0)
    { 
        Messages += " [Please the check fee and ddl1 type selected] "; 
    }
}

//如何以最简洁的方式重写相同的逻辑？

Answer 1

if (((ddl1.SelectedValue == "1" || ddl1.SelectedValue == "100") && Fee > 0) ||
    ((ddl1.SelectedValue == "2" || ddl1.SelectedValue == "200") && Fee == 0 ))
{
    Messages += " [Please the check fee and ddl1 type selected] ";
}

最里面的括号是可选的，用于向读者说明而不是编译。

如果您完全确定SelectedValue永远不会是1,100,2或200以外的其他任何内容，则可以进一步将(ddl1.SelectedValue == "1" || ddl1.SelectedValue == "100")合并到ddl1.SelectedValue.StartsWith("1")。如果选定的值包含其他值，或者总域可能会发生变化，则StartsWith将变得脆弱。

Answer 2

string[] ValidValues = {"1", "100", "2", "200"};
if(Fee >= 0){
    Messages += Array.IndexOf(ValidValues, ddl1.SelectedValue) == -1 ? "" : " [Please the check fee and ddl1 type selected] ";
}