问题描述

我有一个具有多种复杂类型和简单类型的 XSD(文件的一部分如下所示).我需要解析这个文档以从复杂类型中引用的每个简单类型中获取 maxLength.任何人都可以就如何实现这一点提出一些建议吗?我需要以通用方式实现这一点，所以如果我查询Setup_Type"，它应该给出以下输出.谢谢！

I have an XSD with multiple complex types and simple types (part of the file shown below). I need to parse this document to get maxLength from each of the simpletypes that are referenced in the complex types. Can anyone please throw some advice on how to implement this? I need to implement this in a generic way so if I query on "Setup_Type" it should give the below output. Thank you!

NewSetup/Amount = 12(由/"分隔的元素标签的名称属性和嵌套simpleType的maxLength)

NewSetup/Amount = 12 (The name attributes from element tags separated by "/" and maxLength from the nested simpleType)

新设置/名称 = 50

NewSetup/Name = 50

<xsd:complexType name="Setup_Type">
  <xsd:sequence>
    <xsd:element name="NewSetup" type="NewSetup_Type" minOccurs="1" maxOccurs="1" />
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="NewSetup_Type">
  <xsd:sequence>
    <xsd:element name="Amount" type="Amount_Type"  minOccurs="1" maxOccurs="1" />
    <xsd:element name="Name" type="Name_Type"  minOccurs="1" maxOccurs="1" />
  </xsd:sequence>
</xsd:complexType>

<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>

<xsd:simpleType name="Name_Type">
  <xsd:annotation>
    <xsd:documentation>Name</xsd:documentation>
  </xsd:annotation>
  <xsd:restriction base="xsd:string">
    <xsd:maxLength value="50" />
  </xsd:restriction>
</xsd:simpleType>

推荐答案

过去我看到过类似的问题(完全披露，我问过类似的问题 问题我自己).解析 XSD 不适合胆小的人.

I have seen similar questions asked in the past (full disclosure, I've ask a similar question myself). Parsing an XSD is not for the faint of heart.

您基本上有 2 个选项，第一个更容易实现，但更容易通过对 XSD 的微小更改来破坏.第二个更强大但难以实施.

You basically have 2 options, first is easier to implement, but can be broken more easily by minor changes to the XSD. the 2nd is a more robust but hard to implement.

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 XDocument 中，然后通过 LINQ 读取它.

Parsing the XSD with LINQ (or other C# XML parser if you prefer). Since an XSD is just an XML, you can load it into an XDocument and just read it via LINQ.

只是您自己的 XSD 示例:

For just a sample of your own XSD:

<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:

You can access the 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.

This does not offer a very easy method for parsing by type name, especially for extended types. To use this you need to know the exact path for each element you are looking for.

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)，所以我鼓励你看看我的我在上面链接的自己的问题.在其中，我链接了一个 很棒的博客，它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(该博客显示了一个带有 XmlReader 的实现，其中包含针对相关 XSD 进行验证的 XML，但您可以通过直接加载轻松完成此操作XSD 并对其进行解析.

This is far too complex for a quick answer (note: see the edit below - I had some time and put together a working solution), so I am going to encourage you to look at my own question I linked above. In it, I linked a great blog that shows how to seriously break down the XSD into pieces and might allow you to perform the type of search you want. You have to decide if it is worth the effort to develop it (the blog shows an implementation with XmlReader that contains an XML that is validated against the XSD in question, but you can easily accomplish this by directly loading the XSD and parsing it.

在博客中找到的两个关键思想是:

2 key idea to find in the blog are:

// 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.

I actually tried the same thing last year to parse an XSD as part of a complicated data validation method. It took me the better part of a week to really understand what was happening an to adapt the methods in the blog to suit my purposes. It is definitely the best way to implement exactly what you want.

如果您想使用独立架构尝试此操作，可以将 XSD 加载到 XmlSchemaSet 对象中，然后使用 GlobalTypes 属性帮助您找到特定类型你正在寻找.

If you want to try this with a standalone schema, you can load the XSD into an XmlSchemaSet object, then use the GlobalTypes property to help you find the specific type you are looking for.

我调出旧代码并开始整理代码以帮助您.

I pulled up my old code and started putting together the code to help you.

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您想要的结果.它应该非常适合处理更复杂的结构.

The following methods should give you close to what you want based on the XSD you provided. It should be pretty adaptable to deal with more complex structures.

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;
}

那么用法就很简单了，你只需要调用 GetElementMaxLength(String) 方法，它就会以你提供的格式返回一个名称的字典，并将值作为最大长度:

Then the usage is pretty simple, you just need to call the GetElementMaxLength(String) method and it will return a dictionary of the names in the format you provided with the value as the max length:

var results = GetElementMaxLength("Setup_Type");

foreach (var item in results)
{
    Console.WriteLine("{0} | {1}", item.Key, item.Value);                
}

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