使用EntityFramework,如何访问DisplayName的外键列? [英] With EntityFramework, how to access DisplayName for foreign key columns?
问题描述
我有以下注释:
[Display(Name = "NotImportant", ResourceType = typeof(MyResxFile))]
public int? PhoneModel { get; set; } // this is the id
[Display(Name = "Important", ResourceType = typeof(MyResxFile))]
public virtual PhoneModel PhoneModel1 { get; set; } // this is the object
我使用以下方法获取显示名称:
I use the following method to get the display name :
PropertyInfo pi = SomeObject.GetProperties[0]; // short example
columnName = ReflectionExtensions.GetDisplayName(pi);
它适用于除之外的所有列,代码没有找到自定义/显示属性对于诸如PhoneModel1之类的列,即使有一个属性清楚。它适用于 int?,但是我不需要 id 的标题,我需要在PhoneModel1中实际值的标题。
It works for all columns except the code finds no custom/display attribute for columns such as PhoneModel1 even if there is clearly one attribute. It works for the int? but I don't need the header for the id, I need the header for the actual value, which is in PhoneModel1.
public static class ReflectionExtensions
{
public static T GetAttribute<T>(this MemberInfo member, bool isRequired)
where T : Attribute
{
var attribute = member.GetCustomAttributes(typeof(T), false).SingleOrDefault();
if (attribute == null && isRequired)
{
throw new ArgumentException(
string.Format(
CultureInfo.InvariantCulture,
"The {0} attribute must be defined on member {1}",
typeof(T).Name,
member.Name));
}
return (T)attribute;
}
public static string GetDisplayName(PropertyInfo memberInfo)
{
var displayAttribute = memberInfo.GetAttribute<DisplayAttribute>(false);
if (displayAttribute != null)
{
ResourceManager resourceManager = new ResourceManager(displayAttribute.ResourceType);
var entry = resourceManager.GetResourceSet(Thread.CurrentThread.CurrentUICulture, true, true)
.OfType<DictionaryEntry>()
.FirstOrDefault(p => p.Key.ToString() == displayAttribute.Name);
return entry.Value.ToString();
}
else
{
var displayNameAttribute = memberInfo.GetAttribute<DisplayNameAttribute>(false);
if (displayNameAttribute != null)
{
return displayNameAttribute.DisplayName;
}
else
{
return memberInfo.Name;
}
}
}
}
推荐答案
您的 GetDisplayName
扩展方法应如下所示:
Your GetDisplayName
extension method should look like this:
public static string GetDisplayName(this PropertyInfo pi)
{
if (pi == null)
{
throw new ArgumentNullException(nameof(pi));
}
return pi.IsDefined(typeof(DisplayAttribute)) ? pi.GetCustomAttribute<DisplayAttribute>().GetName() : pi.Name;
}
并使用它:
PropertyInfo pi = SomeObject.GetProperties[0];
string columnName = pi.GetDisplayName();
请注意,如果该属性未定义 DisplayName
属性我们返回属性名。
Note that if the property doesn't define a DisplayName
attribute we return the property name.
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