{C#-02} 简化代码

目的

• 简简单单，才能明明白白
• 用时与复杂度成反比
• 以下方法，面向函数级，已实测。
• 方法1：使用?:

namespace SimplifyCode
{
    public class Choice
    {
        bool weekend = true;

        // 常规
        public string Complex()
        {
            if (weekend)
            {
                return "rest";
            }
            else
            {
                return "work";
            }
        }

        // 卫函数，减少层次
        public string Guard()
        {
            if (weekend) return "rest";

            return "work";
        }

        // 条件操作符
        public string Operator()
        {
            return weekend ? "rest" : "work";
        }

        // 表达式
        public string Lambda()
            => weekend ? "rest" : "work";
    }
}

• 方法2：使用||

using System.Windows.Forms;

namespace SimplifyCode
{
    public class Validation
    {
        public void Complex()
        {
            if (IsWrongLicense()) return;

            IsWrongPassword();
        }

        public void Simple()
        {
            var result =
                IsWrongLicense() ||
                IsWrongPassword();
        }

        private bool IsWrongLicense()
        {
            bool result = true; // 省略具体判定

            if (result)
            {
                MessageBox.Show("Not right license!");
            }

            return result;
        }

        private bool IsWrongPassword()
        {
            bool result = true; // 省略具体判定

            if (result)
            {
                MessageBox.Show("Not right password!");
            }

            return result;
        }
    }
}

• 方法3：使用?.

using System;
using System.Windows.Forms;

namespace SimplifyCode
{
    public delegate void ClickContent(string content);

    public class UserCtrl
    {
        public event ClickContent ContentClicked;

        public void Complex_Click(object sender, EventArgs e)
        {
            if (ContentClicked == null) return;

            ContentClicked.Invoke((sender as TextBox).Text);
        }

        public void Simple_Click(object sender, EventArgs e)
        {
            ContentClicked?.Invoke((sender as TextBox).Text);
        }
    }

    public class SomeForm
    {
        private UserCtrl ctrl = new UserCtrl();

        public SomeForm()
        {
            ctrl.ContentClicked += OnContentClicked;
        }

        private void OnContentClicked(string content) { }
    }
}

• 方法4：使用??

namespace SimplifyCode
{
    public class Info
    {
        public string ServerIP { get; set; }
        public string DefaultServerIP { get; set; }
    }

    public class App
    {
        public Info info = new Info();

        public string Complex_GetServerIP()
        {
            string serverIP = info.ServerIP;
            if (info.ServerIP != null)
            {
                return serverIP;
            }

            return info.DefaultServerIP;
        }

        public string Simple_GetServerIP()
            => info.ServerIP ?? info.DefaultServerIP;
    }
}

• 方法5：使用$

namespace SimplifyCode
{
    public class Sql
    {
        private string schema, table;

        public Sql(string schema, string table)
        {
            this.schema = schema;
            this.table = table;
        }

        public string Complex_GetMaxID()
        {
            return string.Format($"use {0};"
                + $"\n select max(id) from {1};",
                schema, table);
        }

        public string Simple_GetMaxID()
        {
            return $"use {schema};"
                + $"\n select max(id) from {table};";
        }
    }
}