从C#中的主类以外的类访问字典

huangapple
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英文:

Accessing a Dictionary from a Class other than the Main() Class in C#

问题

I've just started working with C# in January and am working on a simple game for a project. I have the Program.cs class which contains the Main() class, player.cs which contains the majority of actions that a player can take, and building.cs which holds the building a player can purchase.

building.cs

  1. namespace Game
  2. {
  3.     public class building
  4.     {
  5.         public int price { get; }
  6.         public bool owned { get; set; }
  7.         public string? name { get; }
  8.         public int owner { get; set; }
  10.         public building(string name, int price, bool owned, int owner)
  11.         {
  12.             this.name = name;
  13.             this.price = price;
  14.             this.owned = owned;
  15.             this.owner = owner;
  16.         }
  17.     }
  19.     public class buildingDict
  20.     {
  21.         public static Dictionary<string, building> InitializeBuildings()
  22.         {
  23.             building wheatfield = new building("wheatfield", 4, false, 1);
  24.             var buildings = new Dictionary<string, building>();
  25.             buildings.Add("wheatfield", wheatfield);
  26.             return buildings; 
  27.         }
  28.     }
  30. }

Now, I would like to be able to access this from my player.cs class, but it doesn't seem possible.

I can access it from Program.cs Main()

  1. namespace Game
  2. {
  3.     static void Main()
  4.     {
  5.         var ownedbuildings = buildingDict.InitializeBuildings();
  6.         Console.WriteLine($"There are {ownedbuildings.Count} buildings for sale");
  7.         Console.WriteLine($"{ownedbuildings["wheatfield"].name} is sold at ${ownedbuildings["wheatfield"].price}");
  8.     }
  9. }

Which returns

  1. There are 1 buildings for sale
  2. wheatfield is sold at $4

But when I attempt to access it from Player.cs I get errors and I'm not sure why or if it is even possible to access a Dictionary from a separate class that isn't Main().

  1. namespace Game
  2. {
  3.     public class player
  4.     {
  5.         var OwnedBuildings = buildingDict.InitializeBuildings();
  7.         public void purchasebuilding()
  8.         {
  9.             //do something with the building dictionary.
  10.         }
  11.     }
  12. }

The error I get is on the var keyword which states, "The contextual keyword 'var' may only appear with a local variable declaration or in script code".

I would like to keep all the logic for what players can do to the player class solely and leave the mechanics of the game for the Main().

英文:

I've just started working with C# in January and am working on a simple game for a project. I have the Program.cs class which contains the Main() class, player.cs which contains the majority of actions that a player can take, and building.cs which holds the building a player can purchase.

building.cs

  1. namespace Game
  2. {
  3.     public class building
  4.     {
  5.         public int price { get; }
  6.         public bool owned { get; set; }
  7.         public string? name { get; }
  8.         public int owner { get; set; }
  10.         public building(string name, int price, bool owned, int owner)
  11.         {
  12.             this.name = name;
  13.             this.price = price;
  14.             this.owned = owned;
  15.             this.owner = owner;
  16.         }
  17.     }
  19.     public class buildingDict
  20.     {
  21.         public static Dictionary&lt;string, building&gt; InitializeBuildings()
  22.         {
  23.             building wheatfield = new building(&quot;wheatfield&quot;, 4, false, 1);
  24.             var buildings = new Dictionary&lt;string, building&gt;();
  25.                 buildings.add(&quot;wheatfield&quot;, wheatfield);
  26.             return buildings; 
  27.         }
  28.     }
  30. }

Now, I would like to be able to access this from my player.cs class, but it doesn't seem possible.

I can access it from Progam.cs Main()

  1. namespace Game
  2. {
  3.     static void Main()
  4.     {
  5.         var ownedbuildings = buildingDict.InitializeBuildings();
  6.         Console.WriteLine($&quot;There are {ownedbuildings.Count} buildings for sale&quot;);
  7.         Console.WriteLine($&quot;{ownedbuildings[&quot;wheatfield&quot;].name} is sold at ${ownedbuildings[&quot;wheatfield&quot;].price}&quot;);
  8.     }
  9. }

Which returns

  1. There are 1 buildings for sale
  2. wheatfield is sold at $4

But when I attempt to access it from Player.cs I get errors and I'm not sure why or if it is even possible to access a Dictionary from a separate class that isn't Main().

  1. namespace Game
  2. {
  3.     public class player
  4.     {
  5.         var OwnedBuildings = buildingDict.InitializeBuildings();
  7.         public void purchasebuilding()
  8.         {
  9.             \\do something with the building dictionary.
  10.         }
  11.     }
  12. }

The error I get is on the var keyword which states, "The contextual keyword 'var' may only appear with a local variable declaration or in script code".

I would like to keep all the logic for what players can do to the player class solely and leave the mechanics of the game for the Main().

答案1

得分: 1

你应该为玩家添加一个类构造函数（就像你为建筑类所做的那样），接受一个字典对象，而不是尝试引用外部变量作为类属性。

然后，你可以这样做：

  1. static void Main()
  2. {
  3.     var ownedbuildings = buildingDict.InitializeBuildings();
  4.     var p = new player(ownedbuildings);
  5. }

这可能不是最佳的设计，但它允许你在类之间传递引用。

英文:

You should add a class constructor (like you did for building class) for the player that accepts just a dictionary object rather than trying to reference an external variable as a class property.

Then you could do

  1. static void Main()
  2. {
  3.     var ownedbuildings = buildingDict.InitializeBuildings();
  4.     var p = new player(ownedbuildings);

This may not be the best design, but it allows you to pass references between classes.

答案2

得分: 1

如果意图是使每个 player 拥有他们自己的、独立的建筑物集合，但具有相同的默认初始设置，那么使用以下代码：

  1. public class player
  2. {
  3.     private Dictionary<string, building> OwnedBuildings = buildingDict.InitializeBuildings();
  5.     public void purchasebuilding()
  6.     {
  7.         // 使用建筑物字典执行某些操作。
  8.     }
  9. }
英文:

If the intention is for each player to have their OWN, SEPARATE collection of buildings, but with the same default, initial setup, then use:

  1. public class player
  2. {
  4.     private Dictionary&lt;string, building&gt; OwnedBuildings = buildingDict.InitializeBuildings();
  6.     public void purchasebuilding()
  7.     {
  8.         //do something with the building dictionary.
  9.     }
  11. }

答案3

得分: 1

你不能在类的内部，即类作用域内，仅仅使用 "var" 关键字，就像你不能在类的内部放置执行操作的任何代码一样。这只能在构造函数、方法或块作用域中完成。 "Main" 不是一个类，它是 Program 类内的一个方法。

在你的情况下，通常使用 "private" 而不是 var，而且通常与 "readonly" 关键字一起使用。

  1. public class player
  2. {
  3.     private readonly Dictionary<string, building> _ownedbuildings = buildingDict.InitializeBuildings();
  5.     public void purchasebuilding()
  6.     {
  7.         Console.WriteLine($"There are {_ownedbuildings.Count} buildings for sale");
  8.         Console.WriteLine($"{_ownedbuildings["wheatfield"].name} is sold at ${_ownedbuildings["wheatfield"].price}");
  9.     }
  10. }

但以下代码也可以正常工作：

  1. public class player
  2. {
  3.     public void purchasebuilding()
  4.     {
  5.         var _ownedbuildings = buildingDict.InitializeBuildings();
  6.         Console.WriteLine($"There are {_ownedbuildings.Count} buildings for sale");
  7.         Console.WriteLine($"{_ownedbuildings["wheatfield"].name} is sold at ${_ownedbuildings["wheatfield"].price}");
  8.     }
  9. }
英文:

You can not use "var" just inside of a class, in a class scope. The same way as you can not put any code that is doing something inside of a class too. It can be only done in a constructor, method or block scope. "Main" is not a class, it is a method inside of the Program class.

In your case usually used "private" instead of var, also it is usually used with readonly word

  1. public class player
  2. {
  3. 	private readonly Dictionary&lt;string, building&gt; _ownedbuildings = buildingDict.InitializeBuildings();
  5. 	public void purchasebuilding()
  6. 	{
  7. 		Console.WriteLine($&quot;There are {_ownedbuildings.Count} buildings for sale&quot;);
  8. 		Console.WriteLine($&quot;{_ownedbuildings[&quot;wheatfield&quot;].name} is sold at ${_ownedbuildings[&quot;wheatfield&quot;].price}&quot;);
  9. 	}
  10. }

but this will be working

  1. public class player
  2. {
  3. 	public void purchasebuilding()
  4. 	{
  5. 		var _ownedbuildings = buildingDict.InitializeBuildings();
  6. 		Console.WriteLine($&quot;There are {_ownedbuildings.Count} buildings for sale&quot;);
  7. 		Console.WriteLine($&quot;{_ownedbuildings[&quot;wheatfield&quot;].name} is sold at ${_ownedbuildings[&quot;wheatfield&quot;].price}&quot;);
  8. 	}
  9. }

huangapple
  • 本文由 发表于 2023年2月24日 08:40:54
  • 转载请务必保留本文链接：https://go.coder-hub.com/75551655.html
  • c#
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