如何使重復的代碼更加優雅？

Question

我在下面有這個重復的代碼，我假設可以將其合並，但是如果您注意到每個詞典都是不同的通用詞典：

dictionary1是類型

Dictionary<int, ContinuousIntegrationSolution>  

而dictionary2的類型為：

Dictionary<int, BugTracker>

      DataTable dt = GetDataTable("CI");
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            DataRow dr = dt.Rows[i];
            int id = Convert.ToInt32(dr["id"]);
            string name = dr["name"].ToString();
            _dictionary1[id] = new ContinuousIntegrationSolution(){Name = name};
        }

        DataTable dt1 = GetDataTable("Bug_Tracking");

        for (int i = 0; i < dt1.Rows.Count; i++)
        {
            DataRow dr = dt1.Rows[i];
            int id = Convert.ToInt32(dr["id"]);
            string name = dr["name"].ToString();
            _dictionary2[id] = new BugTracker() { Name = name };
        }

        DataTable dt2 = GetDataTable("SDLC");

        for (int i = 0; i < dt2.Rows.Count; i++)
        {
            DataRow dr = dt2.Rows[i];
            int id = Convert.ToInt32(dr["id"]);
            string name = dr["name"].ToString();
            _dictionary3[id] = new SDLCProcess() { Name = name };
        }

---

注意：我已修復下面提到的一些錯字。

Answer 1

public interface INameable
{
    string Name {get;set;}
}

public static IDictionary<int, T> ReadTable<T>(string tableName)
    where T : INameable, new()
{
    DataTable dt = GetDataTable(tableName);
    var dictionary = new Dictionary<int, T>();

    for (int i = 0; i < dt.Rows.Count; i++)
    {
        DataRow dr = dt.Rows[i];
        int id = Convert.ToInt32(dr["id"]);
        string name = dr["name"].ToString();
        dictionary[id] = new T() { Name = name };
    }
    return dictionary;
}

如果您具有動態的c＃4.0，則可以避免INameable導致類型安全性的（部分）損失

一個與Hakon的答案相似但在不暴露字典的情況下是

public IDictionary<int,T> ReadTable<T>(
    string tableName, Action<T, string> onName) 
    where T : new()
{
    var dictionary = new Dictionary<int,T>();
    DataTable table = GetDataTable(tableName);
    foreach (DataRow row in table.Rows) 
    {
        int id = Convert.ToInt32(row["id"]);
        string name = row["name"].ToString();
        var t = new T();
        onName(t, name);
        dictionary[id] = t;
    }
    return dictionary;
}

然后像這樣消耗：

var ci   = ReadTable<ContinuousIntegrationSolution>("CI", 
              (t, name) => t.Name = name);  
var bt   = ReadTable<BugTracker >("Bug_Tracking", 
              (t, name) => t.Name = name);  
var sdlc = ReadTable<SDLCProcess>("SDLC", 
              (t, name) => t.Name = name);  

一種替代的，更靈活的方法，但是由於類型推斷，在調用站點上使用起來仍然相當簡單：

public IDictionary<int,T> ReadTable<T>(string tableName, Func<string,T> create) 
{
    DataTable table = GetDataTable(tableName);
    var dictionary = new Dictionary<int,T>()
    foreach (DataRow row in table.Rows) 
    {
        int id = Convert.ToInt32(row["id"]);
        string name = row["name"].ToString();
        dictionary[id] = create(name);
    }
    return dictionary;
}

然后像這樣消耗：

var ci   = ReadTable("CI", 
               name => new ContinuousIntegrationSolution() {Name = name});  
var bt   = ReadTable("Bug_Tracking", 
               name => new BugTracker() {Name = name});
var sdlc = ReadTable("SDLC", 
               name => new SDLCProcess() {Name = name});

如果您要使用lambda方法，建議您使用后者。

Answer 2

我不會使用建議的接口，而是使用lambda函數執行類似於以下的分配：

public void ReadTable(string tableName, Action<int, string> _setNameAction) {
    DataTable table = GetDataTable(tableName);
    foreach (DataRow row in table.Rows) {
        int id = Convert.ToInt32(row["id"]);
        string name = row["name"].ToString();
        _setNameAction(id, name);
    }
}

並調用如下方法：

ReadTable("CI", (id, name)
    => _dictionary1[id] = new ContinuousIntegrationSolution{Name = name});  
ReadTable("Bug_Tracking", (id, name) 
    => _dictionary2[id] = new BugTracker { Name = name });  
ReadTable("SDLC", (id, name) 
    => _dictionary3[id] = new SDLCProcess { Name = name });  

Answer 3

將其放在帶有工廠方法的函數中以實例化id對象。 像這樣

public delegate T CreateObjectDelegate<T>(string name);
public static void ProcessDataTable<T>(DataTable dt, Dictionary<int, T> dictionary, CreateObjectDelegate<T> createObj)
{
    for (int i = 0; i < dt.Rows.Count; i++)
    {
        DataRow dr = dt.Rows[i];
        int id = Convert.ToInt32(dr["id"]);
        string name = dr["name"].ToString();
        dictionary[id] = createObj(name);
    }
}

static void Main(string[] args)
{
    var dt = new DataTable();
    var dictionary = new Dictionary<int, BugTracker>();
    ProcessDataTable<BugTracker>(dt, dictionary, (name) => { return new BugTracker() { Name = name }; });
}