c# xml writing element with attribute but without value format

<a>
<parm name="InstallPhase" value="install" />
</a>

<a>
        <parm name="InstallPhase" value="install">
        </parm>
</a>

XmlWriterSettings xmlWriterSettings = new XmlWriterSettings();
            xmlWriterSettings.NewLineOnAttributes = true;
            xmlWriterSettings.Indent = true;
            XmlTextReader reader = new XmlTextReader(@"c:\c.xml");
            XmlTextWriter writer = new XmlTextWriter(@"c:\b.xml", null);
            writer.Formatting = Formatting.Indented;
            while (reader.Read())
            {
                switch (reader.NodeType)
                {
                    case XmlNodeType.Element: // The node is an element.
                        Console.Write("<" + reader.Name);
                        writer.WriteStartElement(reader.Name);
                        //writer.
                        Console.WriteLine(">");
                        if (reader.HasAttributes)
                        {
                            Console.WriteLine(reader.Name + " ------------------Attribute");
                            for (int i = 0; i < reader.AttributeCount; i++)
                            {
                                reader.MoveToAttribute(i);
                                Console.WriteLine("Nam: " + reader.Name + ", Value: " + reader.Value);
                                writer.WriteAttributeString(reader.Name, reader.Value);
                            }
                            reader.MoveToElement();
                        }
                        //writer.WriteElementString(reader.Name, null);
                        break;
                    case XmlNodeType.Text: //Display the text in each element.
                        Console.WriteLine(reader.Value);
                        //writer.WriteString(reader.Value);
                        break;
                    case XmlNodeType.EndElement: //Display the end of the element.
                        Console.Write("                       Console.WriteLine(">");
                        writer.WriteFullEndElement();
                        break;
                    case XmlNodeType.XmlDeclaration:
                    case XmlNodeType.ProcessingInstruction:
                        writer.WriteProcessingInstruction(reader.Name, reader.Value);
                        break;
                    case XmlNodeType.Comment:
                        writer.WriteComment(reader.Value);
                        break;
                        
                }
            }
            reader.Close();
            writer.Close();