C#从零开始学习(面向对象)(3)

面向对象

本章所有的代码都放在
https://github.com/hikinazimi/head-first-Csharp

类包含方法,方法中包含完成动作的语句,设计良好的类要合理的命名
一些方法有一个返回类型,要使用return返回对应的类型
以public void为开头,可以不用return
从一个类创建一个新的对象时,称为这个类的一个实例
使用static关键字声明类或者方法声明为静态,访问静态方法或字段不需要创建这个类的一个实列
如果一个字段是静态的,他只有一个副本,由所有实例共享

PickRandomCards选牌程序

using System;
using System.Collections.Generic;
using System.Text;namespace PickRandomCards
{class CardPicker{static Random random = new Random();public static string[] PickSomeCards(int numerOfCards){string[] pickedCards = new string[numerOfCards];for (int i = 0; i < numerOfCards; i++){pickedCards[i] = RandomValue() + " of " + RandomSuit();}return pickedCards;}private static string RandomValue(){//1-4的随机数int value = random.Next(1, 5);if (value == 1) return "Spades";if (value == 2) return "Hearts";if (value == 3) return "Culbs";return "Diamonds";}private static string RandomSuit(){int value = random.Next(1, 14);if (value == 1) return "Ace";if (value == 11) return "Jack";if (value == 12) return "Queen";if (value == 13) return "King";return value.ToString();}}
}

选牌为原型的WPF应用(PickACardUI)

将上面创建的游戏使用WPF构建
首先创建一个名为PickACardUI的WPF项目
然后在项目中添加上个项目中MainWindow.xaml.cs文件,鼠标右键项目名,然后添加文件
在这里插入图片描述
然后在文件中更改命名空间为项目名

使用Grid和StackPanel建立主窗口布局
使用StackPanel堆叠两个控件,使他们在同一个单元格中

        <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center" Margin="20"><Label Content="How many cards should I pick?" FontSize="20"/><Slider x:Name="numberOfCards" Minimum="1" Maximum="15" TickPlacement="BottomRight"IsSnapToTickEnabled="True" AutoToolTipPlacement="TopLeft" Foreground="Black"/></StackPanel>

然后在按钮上定义点击的效果


<Button Grid.Row="1" Content="Pick some cards" FontSize="20" HorizontalAlignment="Center" VerticalAlignment="Center" Click="Button_Click" />private void Button_Click(object sender, RoutedEventArgs e){string[] pickedCards = CardPicker.PickSomeCards((int)numberOfCards.Value);listOfCards.Items.Clear();foreach (string card in pickedCards){listOfCards.Items.Add(card);}}

最终结果如下
在这里插入图片描述

JoeAndBob

创建一个类来跟踪他们分别有多少钱

创建两个"Guy"实例
设置对象的Cash和Name
增加方法来给钱和收钱

using System;
using System.Collections.Generic;
using System.Text;namespace JoeAndBob
{class Guy{public string Name;public int Cash;public void WriteMyInfo(){Console.WriteLine(Name + " has " + Cash + " bucks.");}public int GiveCash(int amount){if (amount <= 0){Console.WriteLine(Name + "says: " + amount + "isn't a vaild amount");return 0;}if (amount > Cash){Console.WriteLine(Name + " says: " + "I don't have the enough cash to give you" + Cash);return 0;}Cash -= amount;return amount;}public void ReceiveCash(int amount){if (amount <= 0){Console.WriteLine(Name + " says: " + amount + " isn't an amount I'll take");}else{Cash += amount;}}}
}