Question

假设我有一个班级

String mUrl= <YOUR_URL>;
InputStreamVolleyRequest request = new     InputStreamVolleyRequest(Request.Method.GET, mUrl,
    new Response.Listener<byte[]>() { 
         @Override 
         public void onResponse(byte[] response) { 
       // TODO handle the response 
        try { 
        if (response!=null) {

          FileOutputStream outputStream;
          String name=<FILE_NAME_WITH_EXTENSION e.g reference.txt>;
            outputStream = openFileOutput(name, Context.MODE_PRIVATE);
            outputStream.write(response);
            outputStream.close();
            Toast.makeText(this, "Download complete.", Toast.LENGTH_LONG).show();
        }
    } catch (Exception e) {
        // TODO Auto-generated catch block
        Log.d("KEY_ERROR", "UNABLE TO DOWNLOAD FILE");
        e.printStackTrace();
    }
  }
} ,new Response.ErrorListener() {

@Override
public void onErrorResponse(VolleyError error) {
// TODO handle the error
error.printStackTrace();
  }
}, null);
      RequestQueue mRequestQueue = Volley.newRequestQueue(getApplicationContext(), new HurlStack());
      mRequestQueue.add(request);

我有一个方法class Item { public int A {get; set} public int B {get; set} public int C {get; set} }，它应该遍历parseData(List<Item> items, <reference to property>)并从每个项目中只获取必需的属性。在C＃中最有效的方法是什么？我应该使用items吗（但我不明白该怎么做）？

Answer 1

要获取属性，您可以使用Func<Item, T>：

// I don't know what this method returns so I used "void".
public void ParseData<T>(List<Item> items, Func<Item, T> propertySelector) {
    // as an example, here's how to get the property of the first item in the list
    var firstItemsProperty = propertySelector(items.First());
    ...
}

您可以通过传递lambda表达式来调用此方法：

ParseData(itemList, x => x.Property1) // "Property1" is a property declared in "Item"

Answer 2

如果你愿意，可以反思一下

public void ParseData(List<Item> items, String PropertyName)
{
    foreach (Item item in items)
    {
        var prop = typeof(Item).GetProperty(PropertyName).GetValue(item, null);            
    }
}

如何在C＃中将属性作为参数传递

2 个答案: