我过去曾看到过类似的问题(完全披露,我自己也问过类似的问题)。解析 XSD 不适合胆小的人。
您基本上有 2 个选项,第一个更容易实现,但可以通过对 XSD 的微小更改更容易破坏。第二个更健壮但难以实施。
选项1:
使用 LINQ(或其他 C# XML 解析器,如果您愿意)解析 XSD。由于 XSD 只是一个 XML,因此您可以将其加载到一个XDocument
并通过 LINQ 读取它。
对于您自己的 XSD 示例:
<xsd:simpleType name="Amount_Type">
<xsd:annotation>
<xsd:documentation>Amount</xsd:documentation>
</xsd:annotation>
<xsd:restriction base="xsd:string">
<xsd:maxLength value="12" />
</xsd:restriction>
</xsd:simpleType>
您可以访问 MaxLength:
var xDoc = XDocument.Load("your XSD path");
var ns = XNamespace.Get(@"http://www.w3.org/2001/XMLSchema");
var length = (from sType in xDoc.Element(ns + "schema").Elements(ns + "simpleType")
where sType.Attribute("name").Value == "Amount_Type"
from r in sType.Elements(ns + "restriction")
select r.Element(ns + "maxLength").Attribute("value")
.Value).FirstOrDefault();
这并没有提供一种非常简单的按类型名称解析的方法,尤其是对于扩展类型。要使用它,您需要知道要查找的每个元素的确切路径。
选项 2:
这对于快速回答来说太复杂了(注意:请参阅下面的编辑 - 我有一些时间并制定了一个可行的解决方案),所以我鼓励您查看我上面链接的我自己的问题。在其中,我链接了一个很棒的博客,该博客展示了如何认真地将 XSD 分解为多个部分,并可能允许您执行所需的搜索类型。您必须决定是否值得努力开发它(该博客显示了一个实现,XmlReader
其中包含一个针对相关 XSD 进行验证的 XML,但您可以通过直接加载 XSD 并对其进行解析来轻松完成此操作。
在博客中找到的 2 个关键思想是:
// in the getRestriction method (reader in this context is an `XmlReader` that
// contains a XML that is being validated against the specific XSD
if (reader.SchemaInfo.SchemaElement == null) return null;
simpleType = reader.SchemaInfo.SchemaElement.ElementSchemaType as XmlSchemaSimpleType;
if (simpleType == null) return null;
restriction = simpleType.Content as XmlSchemaSimpleTypeRestriction;
// then in the getMaxLength method
if (restriction == null) return null;
List<int> result = new List<int>();
foreach (XmlSchemaObject facet in restriction.Facets) {
if (facet is XmlSchemaMaxLengthFacet) result.Add(int.Parse(((XmlSchemaFacet) facet).Value));
去年我实际上尝试了同样的事情来解析 XSD 作为复杂数据验证方法的一部分。我花了一周的大部分时间才真正了解正在发生的事情,并调整博客中的方法以适应我的目的。这绝对是实现您想要的最佳方式。
如果您想使用独立模式尝试此操作,您可以将 XSD 加载到XmlSchemaSet
对象中,然后使用该GlobalTypes
属性来帮助您找到您正在寻找的特定类型。
编辑:
我拿出我的旧代码并开始整理代码来帮助你。
首先加载您的架构:
XmlSchemaSet set; // this needs to be accessible to the methods below,
// so should be a class level field or property
using (var fs = new FileStream(@"your path here", FileMode.Open)
{
var schema = XmlSchema.Read(fs, null);
set = new XmlSchemaSet();
set.Add(schema);
set.Compile();
}
根据您提供的 XSD,以下方法应该可以为您提供接近所需的内容。它应该非常适合处理更复杂的结构。
public Dictionary<string, int> GetElementMaxLength(String xsdElementName)
{
if (xsdElementName == null) throw new ArgumentException();
// if your XSD has a target namespace, you need to replace null with the namespace name
var qname = new XmlQualifiedName(xsdElementName, null);
// find the type you want in the XmlSchemaSet
var parentType = set.GlobalTypes[qname];
// call GetAllMaxLength with the parentType as parameter
var results = GetAllMaxLength(parentType);
return results;
}
private Dictionary<string, int> GetAllMaxLength(XmlSchemaObject obj)
{
Dictionary<string, int> dict = new Dictionary<string, int>();
// do some type checking on the XmlSchemaObject
if (obj is XmlSchemaSimpleType)
{
// if it is a simple type, then call GetMaxLength to get the MaxLength restriction
var st = obj as XmlSchemaSimpleType;
dict[st.QualifiedName.Name] = GetMaxLength(st);
}
else if (obj is XmlSchemaComplexType)
{
// if obj is a complexType, cast the particle type to a sequence
// and iterate the sequence
// warning - this will fail if it is not a sequence, so you might need
// to make some adjustments if you have something other than a xs:sequence
var ct = obj as XmlSchemaComplexType;
var seq = ct.ContentTypeParticle as XmlSchemaSequence;
foreach (var item in seq.Items)
{
// item will be an XmlSchemaObject, so just call this same method
// with item as the parameter to parse it out
var rng = GetAllMaxLength(item);
// add the results to the dictionary
foreach (var kvp in rng)
{
dict[kvp.Key] = kvp.Value;
}
}
}
else if (obj is XmlSchemaElement)
{
// if obj is an XmlSchemaElement, the you need to find the type
// based on the SchemaTypeName property. This is why your
// XmlSchemaSet needs to have class-level scope
var ele = obj as XmlSchemaElement;
var type = set.GlobalTypes[ele.SchemaTypeName];
// once you have the type, call this method again and get the dictionary result
var rng = GetAllMaxLength(type);
// put the results in this dictionary. The difference here is the dictionary
// key is put in the format you specified
foreach (var kvp in rng)
{
dict[String.Format("{0}/{1}", ele.QualifiedName.Name, kvp.Key)] = kvp.Value;
}
}
return dict;
}
private Int32 GetMaxLength(XmlSchemaSimpleType xsdSimpleType)
{
// get the content of the simple type
var restriction = xsdSimpleType.Content as XmlSchemaSimpleTypeRestriction;
// if it is null, then there are no restrictions and return -1 as a marker value
if (restriction == null) return -1;
Int32 result = -1;
// iterate the facets in the restrictions, look for a MaxLengthFacet and parse the value
foreach (XmlSchemaObject facet in restriction.Facets)
{
if (facet is XmlSchemaMaxLengthFacet)
{
result = int.Parse(((XmlSchemaFacet)facet).Value);
break;
}
}
return result;
}
然后使用非常简单,您只需要调用该GetElementMaxLength(String)
方法,它将以您提供的格式返回名称字典,并将值作为最大长度:
var results = GetElementMaxLength("Setup_Type");
foreach (var item in results)
{
Console.WriteLine("{0} | {1}", item.Key, item.Value);
}