無法指定爲'textBoxSettingsMethod'，因爲它是'方法組'

Question

我已查看過有關此錯誤的網頁上有20多頁的網頁。我一直無法找到解決方案。我知道錯誤發生的原因，但無法弄清楚如何解決這個問題。 ：

我只需要爲我的動作分配一個動作，但這些動作必須有一個傳入的參數類型爲字符串。任何想法都非常感激，因爲我一直在爲此奮鬥了一段時間。

public class CommonDemoHelper 
{ 
    static Action<TextBoxSettings> textBoxSettingsMethod(string txtBoxName); 
    static Action<DateEditSettings> dateEditSettingsMethod; 
    static Action<LabelSettings> labelSettingsMethod; 
    static Action<LabelSettings> wideLabelSettingsMethod; 
    static Action<SpinEditSettings> spinEditSettingsMethod; 
    static Action<MemoSettings> memoSettingsMethod; 

    public static Action<TextBoxSettings> TextBoxSettingsMethod(string txtBoxName) 
    { 
     get 
     { 

      if (textBoxSettingsMethod(txtBoxName) == null) 
       //Getting error below cannot assign to method group 
       textBoxSettingsMethod = CreateTextBoxSettingsMethod(txtBoxName); 
      return textBoxSettingsMethod(txtBoxName); 
     } 
    } 

    static Action<TextBoxSettings> CreateTextBoxSettingsMethod(string txtBoxName) 
    { 
     return settings => 
     { 
      settings.ControlStyle.CssClass = "editor"; 
      settings.ShowModelErrors = true; 
      settings.Properties.ValidationSettings.ErrorDisplayMode = ErrorDisplayMode.ImageWithText; 
     }; 
    } 
} 

Answer 1

如果方法（或委託）返回一個值，它將是一個Func<return_type>，而不是一個操作。如果它有輸入參數（參數），那麼這將是一個Func<arg1,arg2,arg3,return_type>

static Func<string, TextBoxSettings> textBoxSettingsMethod; 

public static Func<string, TextBoxSettings> GetTextBoxSettingsMethod(string txtBoxName) 
{ 
    if (textBoxSettingsMethod == null) 
     textBoxSettingsMethod = CreateTextBoxSettingsMethod(txtBoxName); 
    return textBoxSettingsMethod; 
} 

static Func<string, TextBoxSettings> CreateTextBoxSettingsMethod(string txtBoxName) 
{ 
    ... 
} 

這裏Func<string, TextBoxSettings>指定接受字符串參數（輸入），並返回一個TextBoxSettings（輸出）的方法。

此外，由於您需要輸入參數TextBoxSettingsMethod它不能是一個屬性。我改變它是一種方法。

此外，我改變了測試，以確保textBoxSettingsMethod不爲空（不執行結果返回時執行它）。測試textBoxSettingsMethod(txtBoxName) == null調用該方法並測試TextBoxSettings類型的返回值是否爲null。如果您只想知道方法是否已定義，則測試應爲textBoxSettingsMethod == null。

不要混淆表達textBoxSettingsMethod其是其中執行的方法中的方法（或代表）和textBoxSettingsMethod(txtBoxName)。

---

string txtBoxName是什麼意思？你沒有使用它。你對不同的文本框需要不同的方法嗎？這很難說。

---

UPDATE

這總是創建返回取決於文本名稱不同的設置相同的方法（不需要參數string txtBoxName，僅lambda表達式tbName的參數，這將需要一個實際的調用時的參數值）：

static Func<string, TextBoxSettings> CreateTextBoxSettingsMethod() 
{ 
    return tbName => 
    { 
     TextBoxSettings settings; 
     switch (tbName) { 
      case "textbox1": 
      case "textbox2": 
      case "textbox3": 
       settings = new TextBoxSettings { 
        TextBoxName = tbName, 
        ControlStyle = "editor", 
        ShowModelErrors = true 
       }; 
       settings.Properties.ValidationSettings.ErrorDisplayMode = ErrorDisplayMode.ImageWithText; 
       return settings; 
      case "textbox4": 
      case "textbox5": 
       settings = new TextBoxSettings { 
        TextBoxName = tbName, 
        ControlStyle = "displayer", 
        ShowModelErrors = false 
       }; 
       settings.Properties.ValidationSettings.ErrorDisplayMode = ErrorDisplayMode.TextOnly; 
       return settings; 
      default: 
       return new TextBoxSettings { TextBoxName = tbName }; 
     } 
    }; 
} 

---

在相反，這是一個創建返回alwas相同的設置方法不同的方法

static Func<string, TextBoxSettings> CreateTextBoxSettingsMethod(string txtBoxName) 
{ 
    switch (txtBoxName) { 
     case "textbox1": 
     case "textbox2": 
     case "textbox3": 
      return tbName => 
      { 
       var settings = new TextBoxSettings { 
        TextBoxName = tbName, 
        ControlStyle = "editor", 
        ShowModelErrors = true 
       }; 
       settings.Properties.ValidationSettings.ErrorDisplayMode = ErrorDisplayMode.ImageWithText; 
       return settings; 
      }; 
     case "textbox4": 
     case "textbox5": 
      return tbName => 
      { 
       var settings = new TextBoxSettings { 
        TextBoxName = tbName, 
        ControlStyle = "displayer", 
        ShowModelErrors = false 
       }; 
       settings.Properties.ValidationSettings.ErrorDisplayMode = ErrorDisplayMode.TextOnly; 
       return settings; 
      }; 
     default: 
      return tbName => new TextBoxSettings { TextBoxName = tbName }; 
    } 
} 

---

更新＃2

也許你想這個

static Dictionary<string, Func<string, TextBoxSettings>> textBoxSettingsMethod 
    = new Dictionary<string,Func<string,TextBoxSettings>>(); 

public static Func<string, TextBoxSettings> GetTextBoxSettingsMethod(string txtBoxName) 
{ 
    Func<string, TextBoxSettings> method; 
    if (!textBoxSettingsMethod.TryGetValue(txtBoxName, out method)) { 
     method = CreateTextBoxSettingsMethod(txtBoxName); 
     textBoxSettingsMethod.Add(txtBoxName, method); 
    } 
    return method; 
} 

你可以用它像這樣：

Func<string, TextBoxSettings> method; 
TextBoxSettings setting; 

method = GetTextBoxSettingsMethod("textbox1"); 
setting = method("textbox1"); 

// or 

setting = GetTextBoxSettingsMethod("textbox1")("textbox1"); 

// or, if you are sure that all the methods have been assigned 

method = textBoxSettingsMethod["textbox1"]; 
setting = method("textbox1"); 

// or 

setting = textBoxSettingsMethod["textbox1"]("textbox1"); 

但我仍不確定爲什麼要動態創建這些方法。一個簡單的方法返回設置就足夠了

public static TextBoxSettings GetTextBoxSettings(string txtBoxName) 
{ 
    switch (txtBoxName) { 
     // ... 
     default: 
      return null; 
    } 
} 

Answer 2

你聲明textBoxSettingsMethod的方法：

static Action<TextBoxSettings> textBoxSettingsMethod(string txtBoxName); 

時，它看起來像你試圖將其定義爲一個屬性：

static Action<TextBoxSettings> textBoxSettingsMethod; 

雖然自txtBoxName不在CreateTextBoxSettingsMethod中使用，對於你實際要完成的事情有點混淆。