我正在嘗試使用來(lái)更改將我的類序列化為 XML 的方式。我需要排除某些屬性，并按特定順序包含其他屬性。XmlAttributeOverrides我在這里有這個(gè)代碼：// XML Attribute Overrridespublic static XmlAttributeOverrides GetXMLAttributeOverrides(Type theType, List<string> propertiesToInlcudeInOrder, List<string> allColumnNames){ try { if (propertiesToInlcudeInOrder != null) { XmlAttributeOverrides theXMLAttributeOverrides = new XmlAttributeOverrides(); if (propertiesToInlcudeInOrder.Count > 0) { XmlAttributes mainNewXMLAttributes = new XmlAttributes(); mainNewXMLAttributes.XmlIgnore = false; XmlAttributes ignoreXMLAttributes = new XmlAttributes(); ignoreXMLAttributes.XmlIgnore = true; List<string> propertiesToNotInclude = new List<string>(); foreach (string theColumnName in allColumnNames) { string thePropertyName = theColumnName; bool addProperty = true; foreach (string propertyToInclude in propertiesToInlcudeInOrder) { if (thePropertyName == propertyToInclude) { addProperty = false; break; } } if (addProperty) { propertiesToNotInclude.Add(thePropertyName); } }
1 回答
胡說叔叔
TA貢獻(xiàn)1804條經(jīng)驗(yàn) 獲得超8個(gè)贊
您的基本問題是，您正在為每個(gè)屬性添加多個(gè)覆蓋 [XmlElement] 屬性，因?yàn)槟趯?duì)所有屬性使用單個(gè)實(shí)例，這會(huì)累積為所有屬性定義的對(duì)象。mainNewXMLAttributesXmlElementAttribute
要解決此問題，您需要為循環(huán)中的每個(gè)屬性分配一個(gè) fresh，如以下更正和簡(jiǎn)化的版本所示：mainNewXMLAttributesforeach (var propertyNameToIncludeInOrder in propertiesToInlcudeInOrder)GetXMLAttributeOverrides()
public static partial class ReportingManipulation
{
public static XmlAttributeOverrides GetXMLAttributeOverrides(Type theType, IList<string> propertiesToInlcudeInOrder)
{
var allProperties = theType.GetProperties(BindingFlags.Public | BindingFlags.DeclaredOnly | BindingFlags.Instance).Select(p => p.Name);
return GetXMLAttributeOverrides(theType, propertiesToInlcudeInOrder, allProperties);
}
// XML Attribute Overrrides
public static XmlAttributeOverrides GetXMLAttributeOverrides(Type theType, IList<string> propertiesToInlcudeInOrder, IEnumerable<string> allProperties)
{
if (propertiesToInlcudeInOrder == null || propertiesToInlcudeInOrder.Count == 0)
return null;
var theXMLAttributeOverrides = new XmlAttributeOverrides();
// To Add In Order
int counter = 1;
foreach (var propertyNameToIncludeInOrder in propertiesToInlcudeInOrder)
{
// Allocate a fresh instance of XmlAttributes for each property, because we are defining a different
// XmlElementAttribute for each
var mainNewXMLAttributes = new XmlAttributes { XmlIgnore = false };
// Specify the element order XmlElementAttribute and attach to the XmlAttributes
var theXMLElementAttributeToAdd = new XmlElementAttribute { Order = counter };
mainNewXMLAttributes.XmlElements.Add(theXMLElementAttributeToAdd);
// Attach the override XmlElementAttribute to the property propertyNameToIncludeInOrder
theXMLAttributeOverrides.Add(theType, propertyNameToIncludeInOrder, mainNewXMLAttributes);
counter++;
}
// To Ignore
// Using System.Linq.Enumerable.Except()
var propertiesToNotInclude = allProperties.Except(propertiesToInlcudeInOrder);
var ignoreXMLAttributes = new XmlAttributes { XmlIgnore = true };
foreach (var propertyNameToNotInlcude in propertiesToNotInclude)
{
// Attach the override XmlElementAttribute to the property propertyNameToIncludeInOrder
// No need to allocate a fresh instance of ignoreXMLAttributes for each, because the instances would all be identical
theXMLAttributeOverrides.Add(theType, propertyNameToNotInlcude, ignoreXMLAttributes);
}
return theXMLAttributeOverrides;
}
}
為什么你的代碼不起作用？在初始代碼中，您需要執(zhí)行以下操作：
XmlAttributes mainNewXMLAttributes = new XmlAttributes();
mainNewXMLAttributes.XmlIgnore = false;
int counter = 1;
foreach (string propertyNameToIncludeInOrder in propertiesToInlcudeInOrder)
{
XmlElementAttribute theXMLElementAttributeToAdd = new XmlElementAttribute(propertyNameToIncludeInOrder);
theXMLElementAttributeToAdd.ElementName = propertyNameToIncludeInOrder;
theXMLElementAttributeToAdd.Order = counter;
mainNewXMLAttributes.XmlElements.Add(theXMLElementAttributeToAdd);
theXMLAttributeOverrides.Add(theType, propertyNameToIncludeInOrder, mainNewXMLAttributes);
counter++;
}
現(xiàn)在，方法 XmlAttributeOverrides.Add（Type， String， XmlAttributes） 被記錄為按如下方式工作：
將對(duì)象添加到對(duì)象集合中。該參數(shù)指定要重寫的對(duì)象。該參數(shù)指定被覆蓋的成員的名稱。XmlAttributesXmlAttributestypemember
因此，當(dāng)最終構(gòu)造 時(shí)，的內(nèi)容將應(yīng)用于命名參數(shù)。當(dāng)您為所有參數(shù)僅構(gòu)造 實(shí)例時(shí)，其數(shù)組將包含與所有參數(shù)對(duì)應(yīng)的元素名稱！即，您的代碼嘗試將多個(gè)屬性應(yīng)用于每個(gè)命名參數(shù)，僅在覆蓋名稱和順序上有所不同。這說明了您需要將 XmlChoiceIdentifierAttribute 添加到 'TextColumn' 成員的異常 -- 如果屬性值是多態(tài)的，并且您希望將不同的元素名稱分配給不同的值類型，則只能將多個(gè)元素名稱附加到屬性。mainNewXMLAttributesXmlSerializermainNewXMLAttributesXmlElements[XmlElement]
筆記
生成 with 覆蓋時(shí)，必須靜態(tài)緩存它，并在以后重用它以避免嚴(yán)重的內(nèi)存泄漏，如使用 StreamReader 和 XmlSerializer 的內(nèi)存泄漏中所述。XmlSerializer
我不建議無(wú)條件地吞下異常，并在低級(jí)實(shí)用工具方法或?qū)ο髽?gòu)造函數(shù)中將它們作為錯(cuò)誤消息呈現(xiàn)給用戶。
在這里演示工作小提琴。
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