c# -如何遍历类字段和设置属性
c# -如何遍历类字段和设置属性
提问于 2009-04-06 13:29:43
我不确定这是否可能，但我想在不显式引用field对象的情况下遍历一个类并设置一个field成员属性：
public class Employee
{
public Person _person = new Person();
public void DynamicallySetPersonProperty()
{
MemberInfo[] members = this.GetType().GetMembers();
foreach (MemberInfo member in members.Where(a => a.Name == "_person"))
//get the _person field
{
Type type = member.GetType();
PropertyInfo prop = type.GetProperty("Name"); //good, this works, now to set a value for it
//this line does not work - the error is "property set method not found"
prop.SetValue(member, "new name", null);
}
}
}
public class Person
{
public string Name { get; set; }
}在我标记为答案的答案中，您需要添加：
public static bool IsNullOrEmpty(this string source)
{
return (source == null || source.Length > 0) ? true : false;
}回答 6
Stack Overflow用户
回答已采纳
发布于 2009-04-06 14:03:52
public class Person
{
public string Name { get; set; }
}
public class Employee
{
public Person person = new Person();
public void DynamicallySetPersonProperty()
{
var p = GetType().GetField("person").GetValue(this);
p.GetType().GetProperty("Name").SetValue(p, "new name", null);
}
}Stack Overflow用户
发布于 2009-04-06 14:20:11
下面是一个完整的工作示例：
public class Person
{
public string Name { get; set; }
}
class Program
{
static void PropertySet(object p, string propName, object value)
{
Type t = p.GetType();
PropertyInfo info = t.GetProperty(propName);
if (info == null)
return;
if (!info.CanWrite)
return;
info.SetValue(p, value, null);
}
static void PropertySetLooping(object p, string propName, object value)
{
Type t = p.GetType();
foreach (PropertyInfo info in t.GetProperties())
{
if (info.Name == propName && info.CanWrite)
{
info.SetValue(p, value, null);
}
}
}
static void Main(string[] args)
{
Person p = new Person();
PropertySet(p, "Name", "Michael Ellis");
Console.WriteLine(p.Name);
PropertySetLooping(p, "Name", "Nigel Mellish");
Console.WriteLine(p.Name);
}
}编辑:添加了一个循环变量，这样你就可以看到如何循环遍历属性信息对象。
Stack Overflow用户
发布于 2009-04-06 14:40:36
使用我创建的以下扩展方法，您可以设置或获取任何属性值，即使它们是嵌套的
GetPropertyValue(customObject，"Property.Nested.Child.Name")；
或设置
SetPropertyValue(customObject，"Property.Nested.Child.Name"，“我的自定义名称”)；
private class TargetProperty
{
public object Target { get; set; }
public PropertyInfo Property { get; set; }
public bool IsValid { get { return Target != null && Property != null; } }
}
private static TargetProperty GetTargetProperty(object source, string propertyName)
{
if (!propertyName.Contains("."))
return new TargetProperty { Target = source, Property = source.GetType().GetProperty(propertyName) };
string[] propertyPath = propertyName.Split('.');
var targetProperty = new TargetProperty();
targetProperty.Target = source;
targetProperty.Property = source.GetType().GetProperty(propertyPath[0]);
for (int propertyIndex = 1; propertyIndex < propertyPath.Length; propertyIndex++)
{
propertyName = propertyPath[propertyIndex];
if (!string.IsNullOrEmpty(propertyName))
{
targetProperty.Target = targetProperty.Property.GetValue(targetProperty.Target, null);
targetProperty.Property = targetProperty.Target.GetType().GetProperty(propertyName);
}
}
return targetProperty;
}
public static bool HasProperty(this object source, string propertyName)
{
return GetTargetProperty(source, propertyName).Property != null;
}
public static object GetPropertyValue(this object source, string propertyName)
{
var targetProperty = GetTargetProperty(source, propertyName);
if (targetProperty.IsValid)
{
return targetProperty.Property.GetValue(targetProperty.Target, null);
}
return null;
}
public static void SetPropertyValue(this object source, string propertyName, object value)
{
var targetProperty = GetTargetProperty(source, propertyName);
if(targetProperty.IsValid)
{
targetProperty.Property.SetValue(targetProperty.Target, value, null);
}
}这里有几个测试
[TestFixture]
public class ObjectExtensionsTest
{
private class MockClass
{
public MockClass()
{
Nested = new NestedMockClass();
}
public string Id { get; set; }
public string Name { get; set; }
public string GetOnly { get { return "MockClass"; } }
public string SetOnly { set { } }
public NestedMockClass Nested { get; set; }
}
private class NestedMockClass
{
public string NestedId { get; set; }
public string NestedName { get; set; }
public string NestedGetOnly { get { return "NestedMockClass"; } }
public string NestedSetOnly { set { } }
}
[Test]
public void TestShouldFindProperty()
{
MockClass mockObject = new MockClass();
Assert.IsTrue(mockObject.HasProperty("Id"));
Assert.IsTrue(mockObject.HasProperty("Name"));
Assert.IsTrue(mockObject.HasProperty("GetOnly"));
Assert.IsTrue(mockObject.HasProperty("SetOnly"));
Assert.IsTrue(mockObject.HasProperty("Nested"));
Assert.IsTrue(mockObject.HasProperty("Nested.NestedId"));
Assert.IsTrue(mockObject.HasProperty("Nested.NestedName"));
Assert.IsTrue(mockObject.HasProperty("Nested.NestedGetOnly"));
Assert.IsTrue(mockObject.HasProperty("Nested.NestedSetOnly"));
}
[Test]
public void TestShouldGetPropertyValue()
{
MockClass mockObject = new MockClass();
mockObject.Id = "1";
mockObject.Name = "Name";
mockObject.Nested.NestedId = "NestedId";
mockObject.Nested.NestedName = "NestedName";
Assert.AreEqual(mockObject.Id, mockObject.GetPropertyValue("Id"));
Assert.AreEqual(mockObject.Name, mockObject.GetPropertyValue("Name"));
Assert.AreEqual(mockObject.GetOnly, mockObject.GetPropertyValue("GetOnly"));
Assert.AreEqual(mockObject.Nested.NestedId, mockObject.GetPropertyValue("Nested.NestedId"));
Assert.AreEqual(mockObject.Nested.NestedName, mockObject.GetPropertyValue("Nested.NestedName"));
}
[Test]
public void TestShouldSetPropertyValue()
{
MockClass mockObject = new MockClass();
mockObject.SetPropertyValue("Id", "1");
mockObject.SetPropertyValue("Name", "Name");
mockObject.SetPropertyValue("Nested.NestedId", "NestedId");
mockObject.SetPropertyValue("Nested.NestedName", "NestedName");
Assert.AreEqual(mockObject.Id, "1");
Assert.AreEqual(mockObject.Name, "Name");
Assert.AreEqual(mockObject.Nested.NestedId, "NestedId");
Assert.AreEqual(mockObject.Nested.NestedName, "NestedName");
}
}希望你会发现它是有用的。
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原文链接：
https://stackoverflow.com/questions/721441
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