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,不会将其炸毁。我尝试使用 .Any() 但没有成功。
我宁愿不使用 foreach 进行迭代,而宁愿坚持使用 LINQ
非常感谢任何帮助
最佳答案
不要使用 Value
property 获取属性或元素的值。如果缺少节点,您将获得异常。当您转换节点(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。您也可以使用 ??
运算符为缺少的字符串节点提供您自己的默认值(默认情况下您将获得 null)。
result = (string)column.Element("dataType") ?? String.Empty
对 bool 值使用相同的技巧 - 我得到 Nullable<bool>
如果是 null
(缺少节点)然后我分配 false
如果不是 null
,然后节点的值成功分配给不可为空的属性:
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();
关于c# - Linq to Object/XML 其中元素不存在,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/14860831/