如何從文件中讀取某些數據並將其顯示出來？

Question

假設我有一個文件，它包含以下內容：

Game Name: Candy Crush 
Game Type: Match Three 
Game Difficulty Rating: 8 

Game Name: Maplestory 
Game Type: RPG 
Game Difficulty: 6 

Game Name: Runescape 
Game Type: RPG 
Game Difficulty: 6 

Game Name: GTA 
Game Type: Video 
Game Difficulty: 7 

如何發佈僅一個消息框RPG遊戲？我想顯示列出的每個RPG遊戲的所有數據。

我剛纔試過這段代碼，但它似乎是顯示所有它。

private void button3_Click(object sender, EventArgs e) 
{ 
    var file = File.ReadAllText("Games.txt"); 
    var enter = Environment.NewLine; 

    var gamestrings = games.Select(x => string.Format("{0}\r\n{1}\r\n{2}", x.Name, x.Type, x.Difficulty)); 
    MessageBox.Show(string.Join(enter + enter, gamestrings)); 

    var games = file.Split(new[] { enter + enter }, StringSplitOptions.RemoveEmptyEntries).Select(x => x.Split(new[] { enter }, StringSplitOptions.RemoveEmptyEntries)).Select(e => new { Name = e[0], Type = e[1], Difficulty = e[2] }).Where(x => x.Type.Contains("RPG")); 
} 

給我的錯誤：

Cannot use local variable 'games' before it is declared 

A local variable named 'e' cannot be declared in this scope because it would give a  different meaning to 'e', which is already used in a 'parent or current' scope to denote something else 

Answer 1

首先，刪除StreamReader的東西，並留下這個：

var file = File.ReadAllText(@"c:\Games.txt"); 

（請確保你在裏面輸入正確的文件路徑！）

其次，由於你的數據文件有兩個Enter S離開，讓我們的這種優勢。讓我們將字符串分割成份這2分進入，然後除以重新每個輸入有每場比賽的細節到一個單一的記錄，爲此，我們將這個變量方便地定義：

var enter = Environment.NewLine; 

三，LINQ到拯救！！

您可以在lambda語法之間進行選擇：

var games = file.Split(new[] {enter + enter}, StringSplitOptions.RemoveEmptyEntries) 
       .Select(x => x.Split(new[] {enter}, StringSplitOptions.RemoveEmptyEntries)) 
       .Select(e => new {Name = e[0], Type = e[1], Difficulty = e[2]}) 
       .Where(x => x.Type.Contains("RPG")); 

或查詢語法：

var games = from g in file.Split(new[] {enter + enter}, StringSplitOptions.RemoveEmptyEntries) 
      let gamestrings = g.Split(new[] {enter}, StringSplitOptions.RemoveEmptyEntries) 
      let gamerecord = new {Name = gamestrings[0], Type = gamestrings[1], Difficulty = gamestrings[2]} 
      where gamerecord.Type.Contains("RPG") 
      select gamerecord; 

看到了嗎？現在您有包含3個屬性匿名類型的強類型列表：

• 名稱
• 類型
• 難度

這些，你可以，好像他們是普通班操作和訪問他們屬性如下：

var gamestrings = games.Select(x => string.Format("{0}\r\n{1}\r\n{2}", x.Name, x.Type, x.Difficulty)); 
MessageBox.Show(string.Join(enter + enter, gamestrings)); 

Answer 2

你有一對夫婦與代碼和問題的問題。

FileStream inputFileStream = new FileStream("Games.txt", FileMode.Open, FileAccess.Read); 
StreamReader reader = new StreamReader(inputFileStream); 

這將打開一個流以從文件Games.txt中讀取內容。
您密切與流：

inputFileStream.Close(); 
reader.Close(); 

這應該以相反的順序來完成。但是，沒有必要關閉FileStream和StreamReader。關閉FileStream也將關閉StreamReader。

一個更好的辦法是使用using關鍵字：

using (var inputFileStream = new FileStream("Games.txt", FileMode.Open, FileAccess.Read)) 
using (var reader = new StreamReader(inputFileStream)) 
{ 
    ... 
} 

在這樣做，所以你永遠不會忘記關門。

但是所有這些代碼在你的程序中是沒有用的。你完全不使用StreamReader。
相反，你從Games.txt閱讀內容：

string contents = File.ReadAllText("Games.txt"); 

然後告訴它：

MessageBox.Show(contents); 

你真正想要做的是符合像讀行：

using (var inputFileStream = new FileStream("Games.txt", FileMode.Open, FileAccess.Read)) 
using (var reader = new StreamReader(inputFileStream)) 
{ 
    while (reader.Peek() >= 0) 
    { 
    var gameName = reader.ReadLine(); 
    var gameType = reader.ReadLine(); 
    var gameDifficulty = reader.ReadLine(); 
    var emptyLine = reader.ReadLine(); 

    // Here you'll insert the logic to filter out what you want to show. 
    } 
} 

Answer 3

以下是一種方法：

void Main() 
{ 
string[] lines = System.IO.File.ReadAllLines(@"C:\temp\test.txt"); 
var test = new List<string>(); 
foreach (var line in lines) 
{ 
    if (!string.IsNullOrWhiteSpace(line)) 
    { 
     var values = line.Split(':'); 
     test.Add(values[1].Trim()); 
    } 
} 

List<Game> games = new List<Game>(); 
for (int i = 0;i < test.Count();i = i + 3) 
{ 
    Game game = new Game(); 
    game.Name = test[i]; 
    game.Type = test[i+1]; 
    game.Difficulty = test[i+2]; 

    games.Add(game); 
} 
var rpgGames = games.Where(w => w.Type == "RPG"); 
} 

class Game { 
public string Name {get;set;} 
public string Type {get;set;} 
public string Difficulty {get;set;} 
} 

Answer 4

你也可以試試這個：

1. 創建一個包含屬性的遊戲類：

   class Game 
   { 
       public string Name { get; set; } 
       public string Type { get; set; } 
       public string Difficulty { get; set; } 
   } 
   

2. 然後在你的方法，添加以下代碼：

   var lines = File.ReadLines("test.txt"); 
   var games = new List<Game>(); 
   
   var currGame = new Game(); 
   foreach (string line in lines) 
   { 
       var parts = line.Split(':'); 
       if (parts.Length == 1) 
       { 
        games.Add(currGame); 
        currGame = new Game(); 
       } 
       else if (parts[0].EndsWith("Name")) 
        currGame.Name = parts[1].Trim(); 
       else if (parts[0].EndsWith("Type")) 
        currGame.Type = parts[1].Trim(); 
       else 
        currGame.Difficulty = parts[1].Trim(); 
   } 
   
   var output = string.Join(System.Environment.NewLine, games.Where(x => x.Type == "RPG") 
       .Select(x => string.Format("{0} [{1}] => Difficulty: {2}", x.Name, x.Type, x.Difficulty)) 
       .ToArray()); 
   Console.Write(output);