Question

I was trying to append the xml file in the existing file, everything works fine but I have an issue with default namespace when it appends.

This is the code I use to append:

 XmlNode newChild = doc.CreateNode(XmlNodeType.Element, "image", "");
    newChild.Attributes.Append(doc.CreateAttribute("name", filename));

    XmlNode xmlElement = doc.CreateNode(XmlNodeType.Element, "width", null);
    xmlElement.InnerText = widthValue[1].TrimStart();
    newChild.AppendChild(xmlElement);

am getting an output like below

<image d2p1:name="" xmlns:d2p1="test.jpg">
    <width>1024</width>
</image>

but I was trying to append like:

<image name="test.jpg">
    <width>1024</width>
</image>

Answer 1

As others suggested, using LINQ to XML might be easier in general.

But if you want to stick with using XmlDocument, to fix the issue, change your code to the following:

var attribute = doc.CreateAttribute("name");
attribute.Value = filename;
newChild.Attributes.Append(attribute);

The problem with the code you have is that doc.CreateAttribute("foo", "bar") creates an attribute with the name foo in a namespace with the URI bar. That’s really not what you want.