C# 4.0 序列化自定义属性值
鉴于以下类别:C# 4.0 序列化自定义属性值,c#-4.0,json.net,custom-attributes,C# 4.0,Json.net,Custom Attributes,鉴于以下类别: public class PayrollReport { [UiGridColumn(Name = "fullName",Visible = false,Width = "90")] public string FullName { get; set; } [UiGridColumn(Name = "weekStart", CellFilter = "date")] public DateTime WeekStart { get; set; } }
public class PayrollReport
{
[UiGridColumn(Name = "fullName",Visible = false,Width = "90")]
public string FullName { get; set; }
[UiGridColumn(Name = "weekStart", CellFilter = "date")]
public DateTime WeekStart { get; set; }
}
还有这个自定义属性
[AttributeUsage(AttributeTargets.All)]
public class UiGridColumn : Attribute
{
public string CellFilter { get; set; }
public string DisplayName { get; set; }
public string Name { get; set; }
public bool Visible { get; set; }
public string Width { get; set; }
}
我想为每个字段创建一个列表
,其中只包含提供的值(我不希望跳过的属性为空)
是否可以创建一个列表
,其中每个列表
项仅具有提供的值?(我担心这是不可能的,但我想我会问)如果是,怎么办
如果不是,我的第二个首选项是如下所示的字符串数组:
[{"name":"fullName","visible":false,"width":"90"},{"name":"weekStart","cellFilter":"date"}]
public static string SerializeAppliedPropertyAttributes<T>(Type targetClass) where T : Attribute
{
var attributes = targetClass.GetProperties()
.SelectMany(p => p.GetCustomAttributes<T>())
.ToList();
JsonSerializerSettings settings = new JsonSerializerSettings
{
NullValueHandling = NullValueHandling.Ignore,
Formatting = Formatting.Indented
};
return JsonConvert.SerializeObject(attributes, settings);
}
string json = SerializeAppliedPropertyAttributes<UiGridColumn>(typeof(PayrollReport));
[
{
"name": "fullName",
"visible": false,
"width": "90"
},
{
"cellFilter": "date",
"name": "weekStart",
"visible": false
}
]
我不希望通过循环每个属性
和属性
和参数
来手动构建所需的JSON
字符串,但我还没有找到一种简单的方法来实现
public List<Object> GetUiGridColumnDef(string className)
{
Assembly assembly = typeof(DynamicReportService).Assembly;
var type = assembly.GetType(className);
var properties = type.GetProperties();
var columnDefs = new List<object>();
foreach (var property in properties)
{
var column = new Dictionary<string, Object>();
var attributes = property.CustomAttributes;
foreach (var attribute in attributes)
{
if (attribute.AttributeType.Name != typeof(UiGridColumn).Name || attribute.NamedArguments == null)
continue;
foreach (var argument in attribute.NamedArguments)
{
column.Add(argument.MemberName, argument.TypedValue.Value);
}
}
columnDefs.Add(column);
}
return columnDefs;
}
公共列表GetUiGridColumnDef(字符串类名称)
{
Assembly Assembly=typeof(DynamicReportService).Assembly;
var type=assembly.GetType(className);
var properties=type.GetProperties();
var columnDefs=新列表();
foreach(属性中的var属性)
{
var column=newdictionary();
var attributes=property.CustomAttributes;
foreach(属性中的var属性)
{
if(attribute.AttributeType.Name!=typeof(UiGridColumn.Name | | attribute.NamedArguments==null)
继续;
foreach(attribute.NamedArguments中的var参数)
{
添加(argument.MemberName,argument.TypedValue.Value);
}
}
columnDefs.Add(列);
}
返回列defs;
}
有更好的方法吗?如果我正确理解了您的问题,您想序列化应用于类属性的属性列表吗 如果是这样,您可以创建一个助手方法,如下所示:
[{"name":"fullName","visible":false,"width":"90"},{"name":"weekStart","cellFilter":"date"}]
public static string SerializeAppliedPropertyAttributes<T>(Type targetClass) where T : Attribute
{
var attributes = targetClass.GetProperties()
.SelectMany(p => p.GetCustomAttributes<T>())
.ToList();
JsonSerializerSettings settings = new JsonSerializerSettings
{
NullValueHandling = NullValueHandling.Ignore,
Formatting = Formatting.Indented
};
return JsonConvert.SerializeObject(attributes, settings);
}
string json = SerializeAppliedPropertyAttributes<UiGridColumn>(typeof(PayrollReport));
[
{
"name": "fullName",
"visible": false,
"width": "90"
},
{
"cellFilter": "date",
"name": "weekStart",
"visible": false
}
]
您会注意到包含了基本属性
类中的TypeId
属性,并且属性名称不采用驼峰大小写。要解决此问题,您需要使用自定义合同解析程序:
public class SuppressAttributeTypeIdResolver : CamelCasePropertyNamesContractResolver
{
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty prop = base.CreateProperty(member, memberSerialization);
if (member.DeclaringType == typeof(Attribute) && member.Name == "TypeId")
{
prop.ShouldSerialize = obj => false;
}
return prop;
}
}
将解析器添加到helper方法中的序列化设置中,您就可以开始了:
JsonSerializerSettings settings = new JsonSerializerSettings
{
NullValueHandling = NullValueHandling.Ignore,
ContractResolver = new SuppressAttributeTypeIdResolver(),
Formatting = Formatting.Indented
};
现在输出应该如下所示:
[{"name":"fullName","visible":false,"width":"90"},{"name":"weekStart","cellFilter":"date"}]
public static string SerializeAppliedPropertyAttributes<T>(Type targetClass) where T : Attribute
{
var attributes = targetClass.GetProperties()
.SelectMany(p => p.GetCustomAttributes<T>())
.ToList();
JsonSerializerSettings settings = new JsonSerializerSettings
{
NullValueHandling = NullValueHandling.Ignore,
Formatting = Formatting.Indented
};
return JsonConvert.SerializeObject(attributes, settings);
}
string json = SerializeAppliedPropertyAttributes<UiGridColumn>(typeof(PayrollReport));
[
{
"name": "fullName",
"visible": false,
"width": "90"
},
{
"cellFilter": "date",
"name": "weekStart",
"visible": false
}
]
演示小提琴:这几乎是完美的<代码>可见仅为一个属性定义,但它在两个属性中都显示,因为它是
bool
。当我试图使其为空时
,我发现“可见”不是有效的命名属性参数,因为它不是有效的属性参数类型
。建议?您可以使用DefaultValueHandling=DefaultValueHandling。当设置为默认值false
时,忽略设置中的以抑制可见的。但是,对于第一个对象,这也会抑制它,因为您已将其显式设置为false。不幸的是,使用此解决方案,您不能同时使用这两种方法——要么始终包含值,要么仅在值与默认值不同时才包含值。很高兴知道。我同意跳过默认值。但是,我希望默认情况下Visible
为true
,因此我更改了默认值并添加了DefaultValueHandling
代码。它完全按照预期工作。谢谢哦,是的,去小熊队!太好了,我很高兴你能按你想要的方式工作。去吧,小熊们!:-)