c#foreach(对象中的属性)...有一种简单的方法吗？

Question

我有一个包含几个属性的类(如果它有任何区别,则所有都是字符串).
我还有一个列表,其中包含许多不同的类实例.

在为我的类创建一些单元测试时,我决定循环遍历列表中的每个对象,然后循环遍历该对象的每个属性......

我以为这样做会很简单......

foreach (Object obj in theList)
{
     foreach (Property theProperties in obj)
     {
         do some stufff!!;
     }
}

但这没有用!:(我收到此错误...

"foreach语句不能对'Application.Object'类型的变量进行操作,因为'Application.Object'不包含'GetEnumerator'的公共定义"

有没有人知道这样做的方法没有大量的ifs和循环或没有进入任何太复杂的东西？

Answer 1

尝试一下:

foreach (PropertyInfo propertyInfo in obj.GetType().GetProperties())
{
   // do stuff here
}

另请注意,Type.GetProperties()有一个重载,它接受一组绑定标志,因此您可以过滤掉不同条件(如可访问性级别)的属性,有关详细信息,请参阅MSDN:Type.GetProperties Method(BindingFlags)最后但并非最不重要的是不要忘记添加"system.Reflection"程序集引用.

例如,解决所有公共属性:

foreach (var propertyInfo in obj.GetType()
                                .GetProperties(
                                        BindingFlags.Public 
                                        | BindingFlags.Instance))
{
   // do stuff here
}

请告诉我这是否按预期工作.

Answer 2

您可以循环遍历对象的所有非索引属性,如下所示:

var s = new MyObject();
foreach (var p in s.GetType().GetProperties().Where(p => !p.GetGetMethod().GetParameters().Any())) {
    Console.WriteLine(p.GetValue(s, null));
}

由于GetProperties()返回索引器以及简单属性,因此在调用之前需要一个额外的过滤器,GetValue以便知道null作为第二个参数传递是安全的.

您可能需要进一步修改过滤器,以便清除只写和其他不可访问的属性.

Answer 3

你几乎就在那里,你只需要从类型中获取属性,而不是期望以集合或属性包的形式访问属性:

var property in obj.GetType().GetProperties()

从那里你可以这样访问:

property.Name
property.GetValue(obj, null)

使用GetValue第二个参数将允许您指定索引值,这将使用返回集合的属性 - 因为字符串是字符集合,您还可以指定索引以在需要时返回字符.

Answer 4

好没问题:

foreach(object item in sequence)
{
    if (item == null) continue;
    foreach(PropertyInfo property in item.GetType().GetProperties())
    {
        // do something with the property
    }
}

Answer 5

我在此页面上寻找类似问题的答案，我写了几个类似问题的答案，可能会对进入此页面的人有所帮助。

班级名单

List<T>类表示可以通过索引访问的对象列表。它位于 System.Collection.Generic 命名空间下。List 类可用于创建不同类型的集合，如整数、字符串等。List 类还提供搜索、排序和操作列表的方法。

具有属性的类：

class TestClss
{
    public string id { set; get; }
    public string cell1 { set; get; }
    public string cell2 { set; get; }
}
var MyArray = new List<TestClss> {
    new TestClss() { id = "1", cell1 = "cell 1 row 1 Data", cell2 = "cell 2 row 1 Data" },
    new TestClss() { id = "2", cell1 = "cell 1 row 2 Data", cell2 = "cell 2 row 2 Data" },
    new TestClss() { id = "3", cell1 = "cell 1 row 2 Data", cell2 = "cell 2 row 3 Data" }
};
foreach (object Item in MyArray)
{
    Console.WriteLine("Row Start");
    foreach (PropertyInfo property in Item.GetType().GetProperties())
    {
        var Key = property.Name;
        var Value = property.GetValue(Item, null);
        Console.WriteLine("{0}={1}", Key, Value);
    }
}

或者，带有字段的类：

class TestClss
{
    public string id = "";
    public string cell1 = "";
    public string cell2 = "";
}
var MyArray = new List<TestClss> {
    new TestClss() { id = "1", cell1 = "cell 1 row 1 Data", cell2 = "cell 2 row 1 Data" },
    new TestClss() { id = "2", cell1 = "cell 1 row 2 Data", cell2 = "cell 2 row 2 Data" },
    new TestClss() { id = "3", cell1 = "cell 1 row 2 Data", cell2 = "cell 2 row 3 Data" }
};
foreach (object Item in MyArray)
{
    Console.WriteLine("Row Start");
    foreach (var fieldInfo in Item.GetType().GetFields())
    {
        var Key = fieldInfo.Name;
        var Value = fieldInfo.GetValue(Item);
    }

}

或者，对象列表（没有相同的单元格）：

var MyArray = new List<object> {
    new { id = "1", cell1 = "cell 1 row 1 Data", cell2 = "cell 2 row 1 Data" },
    new { id = "2", cell1 = "cell 1 row 2 Data", cell2 = "cell 2 row 2 Data" },
    new { id = "3", cell1 = "cell 1 row 2 Data", cell2 = "cell 2 row 3 Data", anotherCell = "" }
};
foreach (object Item in MyArray)
{
    Console.WriteLine("Row Start");
    foreach (var props in Item.GetType().GetProperties())
    {
        var Key = props.Name;
        var Value = props.GetMethod.Invoke(Item, null).ToString();
        Console.WriteLine("{0}={1}", Key, Value);
    }
}

或者，对象列表（它必须具有相同的单元格）：

var MyArray = new[] {
    new { id = "1", cell1 = "cell 1 row 1 Data", cell2 = "cell 2 row 1 Data" },
    new { id = "2", cell1 = "cell 1 row 2 Data", cell2 = "cell 2 row 2 Data" },
    new { id = "3", cell1 = "cell 1 row 2 Data", cell2 = "cell 2 row 3 Data" }
};
foreach (object Item in MyArray)
{
    Console.WriteLine("Row Start");
    foreach (var props in Item.GetType().GetProperties())
    {
        var Key = props.Name;
        var Value = props.GetMethod.Invoke(Item, null).ToString();
        Console.WriteLine("{0}={1}", Key, Value);
    }
}

或者，对象列表（带键）：

var MyArray = new {
    row1 = new { id = "1", cell1 = "cell 1 row 1 Data", cell2 = "cell 2 row 1 Data" },
    row2 = new { id = "2", cell1 = "cell 1 row 2 Data", cell2 = "cell 2 row 2 Data" },
    row3 = new { id = "3", cell1 = "cell 1 row 2 Data", cell2 = "cell 2 row 3 Data" }
};
// using System.ComponentModel;  for TypeDescriptor
foreach (PropertyDescriptor Item in TypeDescriptor.GetProperties(MyArray))
{
    string Rowkey = Item.Name;
    object RowValue = Item.GetValue(MyArray);
    Console.WriteLine("Row key is: {0}", Rowkey);
    foreach (var props in RowValue.GetType().GetProperties())
    {
        var Key = props.Name;
        var Value = props.GetMethod.Invoke(RowValue, null).ToString();
        Console.WriteLine("{0}={1}", Key, Value);
    }
}

OR，字典列表

var MyArray = new List<Dictionary<string, string>>() {
    new Dictionary<string, string>() { { "id", "1" }, { "cell1", "cell 1 row 1 Data" }, { "cell2", "cell 2 row 1 Data" } },
    new Dictionary<string, string>() { { "id", "2" }, { "cell1", "cell 1 row 2 Data" }, { "cell2", "cell 2 row 2 Data" } },
    new Dictionary<string, string>() { { "id", "3" }, { "cell1", "cell 1 row 3 Data" }, { "cell2", "cell 2 row 3 Data" } }
};
foreach (Dictionary<string, string> Item in MyArray)
{
    Console.WriteLine("Row Start");
    foreach (KeyValuePair<string, string> props in Item)
    {
        var Key = props.Key;
        var Value = props.Value;
        Console.WriteLine("{0}={1}", Key, Value);
    }
}

祝你好运..