Question

我知道有很多委托/功能示例，但我找不到任何适合我的示例，或者我只是不理解它们。

我正在使用asp.net MVC作为网站，该网站需要一些Web服务调用，以便外部应用程序与我的应用程序进行交互。这些都需要一个函数来执行（转到db和whatnot），并且每次都返回一个类似的数据模型。我想在try / catch中包装每个调用并填充模型。

以下是每次调用时发生的通用代码。

var model = new ResponseDataModel();
try
{
     //execute different code here
}
catch (Exception ex)
{
    model.Error = true;
    model.Message = ex.ToString();
}
return View(model); // will return JSON or XML depending on what the caller specifies

这是我正在使用的控制器方法/功能之一

public ActionResult MillRequestCoil()
{
    var model = new ResponseDataModel();
    try
    {
        /* edit */
        //specific code
        string coilId = "CC12345";

        //additional code
        model.Data = dataRepository.doSomethingToCoil(coilId);

        //replaced code
        //model.Data = new { Coil = coilId, M3 = "m3 message", M5 = "m5 message" };
        model.Message = string.Format("Coil {0} sent successfully", coilId);
    }
    catch (Exception ex)
    {
         model.Error = true;
         model.Message = ex.ToString();
    }
    return View(model);
}

我希望能够以某种方式将特定函数转换为变量以传递给通用代码。我看过代表和匿名函数，但是直到你自己完成它才会让人感到困惑。

Answer 1

将以下内容放在可访问的位置：

public static ActionResult SafeViewFromModel(
    Action<ResponseDataModel> setUpModel)
{
    var model = new ResponseDataModel();
    try
    {
        setUpModel(model);
    }
    catch (Exception ex)
    {
        model.Error = true;
        model.Message = ex.ToString();
    }
    return View(model); 
}

然后将其称为：

public ActionResult MillRequestCoil()
{
    return MyHelperClass.SafeViewFromModel(model =>
    {
        string coilId = "CC12345";
        model.Data = new {
            Coil = coilId,
            M3 = "m3 message",
            M5 = "m5 message" };
        model.Message = string.Format("Coil {0} sent successfully", coilId);
    });
}

Answer 2

public interface IAction{
    public void doAction(ResponseDataModel model);
}

public class Action1 : IAction
{
    public void doAction(ResponseDataModel model)
    {
        string coilId = "CC12345";
        model.Data = new { Coil = coilId, M3 = "m3 message", M5 = "m5 message" };
        model.Message = string.Format("Coil {0} sent successfully", coilId);
    }
}

class Class1
{
    public ActionResult MillRequestCoil(IAction action)
    {
        var model = new ResponseDataModel();
        try
        {
            //specific code
            action.doAction(model);
        }
        catch (Exception ex)
        {
            model.Error = true;
            model.Message = ex.ToString();
        }
        return View(model);
    }
}

使用：

var result = MillRequestCoil(new Action1());

或执行其他代码

var result = MillRequestCoil(new ActionXY());

Answer 3

这是Rawling答案的变体，我相信它具有更好的可读性：

public ActionResult MillRequestCoil()
{
    var model = CreateResponseDataModel(RunSpecificCode);

    return View(model);
}

public ActionResult MillDoSomethingElse ()
{
    var model = CreateResponseDataModel(RunOtherCode);

    return View(model);
}

private ResponseDataModel CreateResponseDataModel(Action<ResponseDataModel> action)
{
    var model = new ResponseDataModel();
    try
    {
        action(model);
    }
    catch (Exception ex)
    {
        model.Error = true;
        model.Message = ex.ToString();
    }
    return model;
}

private void RunSpecificCode(ResponseDataModel model)
{
    /* edit */
    //specific code
    const string coilId = "CC12345";

    //additional code
    model.Data = _dataRepository.DoSomethingToCoil(coilId);

    //replaced code
    //model.Data = new { Coil = coilId, M3 = "m3 message", M5 = "m5 message" };
    model.Message = string.Format("Coil {0} sent successfully", coilId);
}

private void RunOtherCode(ResponseDataModel obj)
{
    // some other piece of code
}

没有lambdas，并且您的特定代码与try / catch和模型构建的模板代码之间的关注点很好。

需要在c＃中的标准try / catch函数中包装函数

3 个答案: