Linq to Object/XML,其中元素没有';不存在
本文关键字:不存在 元素 Object to XML Linq | 更新日期: 2023-09-27 17:58:55
var doc3 = XDocument.Load(@"C:'Projects'ScanBandConfigTesting'ScanBandConfigTesting'ScanBandConfigSmall.xml");
var scanBand = new ScanBand()
{
ListOfForms = (from form in doc3.Descendants("form")
select new ScanBandForm()
{
FormTypes = form.Attribute("types").Value,
ScanBandNumber = form.Attribute("number").Value,
ListOfRows = (from row in form.Descendants("row")
select new ScanBandRow()
{
AllowSpaces = row.Element("allowSpaces").Value.ToLower() == "true",
SplitCharacter = row.Element("splitCharacter").Value,
ListOfColumns = (from column in row.Descendants("column")
select new ScanBandColumn()
{
AlwaysKey = column.Element("allwaysKey").IsEmpty ? false : column.Element("allwaysKey").Value.ToLower() == "true",
DataTypeString = column.Element("dataType").IsEmpty ? string.Empty : column.Element("dataType").Value,
MatchingFieldName = column.Element("matchingFieldName").IsEmpty ? string.Empty : column.Element("matchingFieldName").Value,
NonField = column.Element("nonField").IsEmpty ? false : column.Element("nonField").Value.ToLower() == "true",
RegularExpressionString = column.Element("regularExpression").IsEmpty ? string.Empty : column.Element("regularExpression").Value,
}).ToList()
}).ToList()
}).ToList()
};
XML
<scanBand>
<form types="FormName" number="1">
<row>
<allowSpaces>false</allowSpaces>
<splitCharacter> </splitCharacter>
<column>
<matchingFieldName>FirstField</matchingFieldName>
<dataType>CB</dataType>
<regularExpression></regularExpression>
<allwaysKey>false</allwaysKey>
<nonField>false</nonField>
</column>
<column>
<matchingFieldName>SecondField</matchingFieldName>
<dataType>CB</dataType>
<regularExpression></regularExpression>
<allwaysKey>false</allwaysKey>
<nonField>false</nonField>
</column>
<column>
<matchingFieldName>ThirdField</matchingFieldName>
<dataType>CB</dataType>
<regularExpression></regularExpression>
<!--<allwaysKey></allwaysKey>-->
<nonField>true</nonField>
</column>
</row>
</form>
</scanBand>
目标是当.xml文件中的某个元素不存在时,不要让它爆炸。我试着和他一起玩。Any((,但尚未成功。
我宁愿不使用foreach进行迭代,而宁愿使用LINQ
任何帮助都非常感谢
不要使用Value
属性来获取属性或元素的值。若缺少节点,则会出现异常。当您将节点强制转换(例如转换为字符串(时,如果缺少节点,您将获得该类型的默认值。此外,您还可以使用??
运算符为丢失的字符串节点提供自己的默认值(默认情况下,您将获得null(。
result = (string)column.Element("dataType") ?? String.Empty
与布尔值使用的技巧相同-我得到Nullable<bool>
,如果它是null
(节点丢失(,则我分配false
,如果它不是null
,则节点的值成功分配给不可为null的属性:
ListOfForms =
(from form in doc3.Descendants("form")
select new ScanBandForm() {
FormTypes = (string)form.Attribute("types"),
ScanBandNumber = (string)form.Attribute("number"),
ListOfRows =
(from row in form.Descendants("row")
select new ScanBandRow() {
AllowSpaces = (bool?)row.Element("allowSpaces") ?? false,
SplitCharacter = (string)row.Element("splitCharacter"),
ListOfColumns =
(from column in row.Descendants("column")
select new ScanBandColumn() {
AlwaysKey = (bool?)column.Element("allwaysKey") ?? false,
DataTypeString = (string)column.Element("dataType") ?? String.Empty,
MatchingFieldName = (string)column.Element("matchingFieldName") ?? String.Empty,
NonField = (bool?)column.Element("nonField") ?? false,
RegularExpressionString = (string)column.Element("regularExpression") ?? String.Empty,
}).ToList()
}).ToList()
}).ToList();