问题描述
这是我在.
实际位置如下:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
namespace cns01
{
class Program
{
public class DataFieldInfo2<T>
{
public bool IsSearchValue { get; set; } = false;
public T Value { get; set; }
}
public class SmartRowVertrag
{
public DataFieldInfo2<int> ID { get; set; }
public DataFieldInfo2<string> VSNR { get; set; }
}
static void Main(string[] args)
{
SmartRowVertrag tester = new SmartRowVertrag();
tester.ID = new DataFieldInfo2<int>() { Value = 777, IsSearchValue = false };
tester.VSNR = new DataFieldInfo2<string>() { Value = "234234234", IsSearchValue = true };
var g = RetData3(tester);
}
public static object RetData3(object fsr)
{
object retVal = new object();
var props = fsr.GetType().GetProperties();
foreach (var prop in props)
{
PropertyInfo propInfo = prop.GetType().GetProperty("IsSearchValue"); // <-- here I get null
propInfo = prop.PropertyType.GetProperty("IsSearchValue"); // here I get a propertyInfo, but...
dynamic property = propInfo.GetValue(fsr, null); // ...<-- here fires error
var result = property.IsSearchValue;
if (result == true)
{
// doThis
}
}
return retVal;
}
}
}
我确实需要获取存储在 IsSearchValue
中的布尔值来完成操作.
I do need to get the boolean value stored in IsSearchValue
to to accomplish things.
预先感谢.
我非常感谢任何有帮助的答案.
I mostly appreciate any helping answer.
推荐答案
fsr
是 SmartRowVertrag
.您正在尝试从中获取 IsSearchValue
-但它不存在.
fsr
is the SmartRowVertrag
. You're trying to get the IsSearchValue
from that - but it doesn't exist.
相反,您需要两次调用 GetValue
-在 prop
上调用一次,并传入 fsr
(因此等效于使用 fsr.ID
或 dsr.VSNR
),然后在 propInfo
上传递一次第一次调用的结果.
Instead, you'll need to call GetValue
twice - once on prop
, passing in fsr
(so which is equivalent to using fsr.ID
or dsr.VSNR
) and then once on propInfo
passing in the result of that first call.
接下来,您使用 dynamic
的原因是尝试根据 propInfo.GetValue()
的结果获取 IsSearchValue
-您正在尝试评估 something.IsSearchValue.IsSearchValue
有效.
Next, your dynamic
use is trying to get IsSearchValue
on the result of propInfo.GetValue()
- you're trying to evaluate something.IsSearchValue.IsSearchValue
, effectively.
以下是该部分的更正代码:
Here's corrected code for that part:
public static object RetData3(object fsr)
{
object retVal = new object();
var props = fsr.GetType().GetProperties();
foreach (var prop in props)
{
PropertyInfo propInfo = prop.PropertyType.GetProperty("IsSearchValue");
if (propInfo != null)
{
object fieldInfo = prop.GetValue(fsr);
object isSearchValue = propInfo.GetValue(fieldInfo);
if (isSearchValue.Equals(true))
{
Console.WriteLine($"{prop.Name} has a searchable field");
}
}
}
return retVal;
}
如果您具有实现了 DataFieldInfo2< T>
的非泛型接口或基类,则可以避免两次使用反射.例如:
You could avoid using reflection twice though if you had either a non-generic interface that DataFieldInfo2<T>
implemented, or a base class. For example:
public interface IDataFieldInfo
{
bool IsSearchValue { get; }
}
public class DataFieldInfo2<T> : IDataFieldInfo
{
...
}
然后,您可以使反射代码更清晰:
You could then make your reflection code much clearer:
public static object RetData3(object fsr)
{
var fieldProperties = fsr.GetType().GetProperties()
.Where(prop => typeof(IDataFieldInfo).IsAssignableFrom(prop.PropertyType));
foreach (var fieldProperty in fieldProperties)
{
var field = (IDataFieldInfo) fieldProperty.GetValue(fsr);
if (field.IsSearchValue)
{
Console.WriteLine($"{fieldProperty.Name} is a search value field");
}
}
// We don't actually know what you're trying to return
return null;
}
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