C# XML空白命名空间

我正在用以下标题将一个对象序列化为XML

<agr:ABWInvoice 
    xmlns:agr="http://services.agresso.com/schema/ABWInvoice/2011/11/14"
    xsi:schemaLocation="http://services.agresso.com/schema/ABWInvoice/2011/11/14 http://services.agresso.com/schema/ABWInvoice/2011/11/14/ABWInvoice.xsd" 
    xmlns:agrlib="http://services.agresso.com/schema/ABWSchemaLib/2011/11/14" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 >

我也尝试了以下内容，但没有给出所需的输出：

XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
ns.Add("xsi", "http://www.w3.org/2001/XMLSchema-instance");
ns.Add("agrlib", "http://services.agresso.com/schema/ABWSchemaLib/2006/11/20");
ns.Add("", "http://services.agresso.com/schema/ABWInvoice/2006/11/20");

更新：@Vladimir Frolov引导我使用以下方法解决问题：

[Serializable]
[XmlRootAttribute(Namespace = "http://services.agresso.com/schema/ABWInvoice/2006/11/20", IsNullable = true)]
public class ABWInvoice2006
{
...
}

---

尝试在XmlSerializer构造函数中指定XmlRootAttribute。

---

下面是一个。

尝试在XmlSerializer构造函数中指定XmlRootAttribute。 这是一个例子

XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
ns.Add("xsi", "http://www.w3.org/2001/XMLSchema-instance");
ns.Add("agrlib", "http://services.agresso.com/schema/ABWSchemaLib/2006/11/20");
ns.Add("", "http://services.agresso.com/schema/ABWInvoice/2006/11/20");

[Serializable]
[XmlRootAttribute(Namespace = "http://services.agresso.com/schema/ABWInvoice/2006/11/20", IsNullable = true)]
public class ABWInvoice2006
{
...
}