WCF-Soap标头在安全元素中两次引用命名空间

这是一个有点乏味的问题。。我已经构建了一个WCF来使用WS-Security，在我的日志中如下所示：

<h:Security xmlns:h="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" 
              xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
  <UsernameToken>
    <Username>
      <!-- Removed-->
    </Username>
    <Password>
      <!-- Removed-->
    </Password>
  </UsernameToken>
</h:Security>

问题是，为什么同一个命名空间被引用两次（"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"）？我知道如果同一个命名空间被引用两次并不重要，只要元素引用的是正确的命名空间，但我确实想知道它为什么这么做。

我的代码：

[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]
[System.ServiceModel.MessageContractAttribute(IsWrapped = false)]
public partial class InventoryCountRequest
{
  [System.ServiceModel.MessageHeaderAttribute(Namespace = "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd")]
  public Security Security;
  //Other MessageHeader and MessageBody attributes
}
[System.CodeDom.Compiler.GeneratedCodeAttribute("svcutil", "3.0.4506.2152")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(Namespace = "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd")]
public partial class Security
{
  private UsernameToken usernameTokenField;
    [System.Xml.Serialization.XmlElementAttribute(Order = 0)]
    public UsernameToken UsernameToken
    {
       get{return this.usernameTokenField;}
       set{this.usernameTokenField = value;}
    }
}
[System.CodeDom.Compiler.GeneratedCodeAttribute("svcutil", "3.0.4506.2152")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(Namespace = "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd")]
public partial class UsernameToken
{
  private string usernameField;
  private Password passwordField;
  [System.Xml.Serialization.XmlElementAttribute(Order = 0)]
  public string Username
  {
    get{return this.usernameField;}
    set{this.usernameField = value;}
  }
  [System.Xml.Serialization.XmlElementAttribute(Order = 1)]
  public Password Password
  {
    get{return this.passwordField;}
    set{this.passwordField = value;}
  }
}
[System.CodeDom.Compiler.GeneratedCodeAttribute("svcutil", "3.0.4506.2152")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(Namespace = "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd")]
public partial class Password
{
  private string typeField;
  private string valueField;
  [System.Xml.Serialization.XmlAttributeAttribute()]
  public string Type
  {
    get{return this.typeField;}
    set{this.typeField = value;}
  }
  [System.Xml.Serialization.XmlTextAttribute()]
  public string Value
  {
    get{return this.valueField;}
    set{this.valueField = value;}
  }
}

非常感谢您阅读