私はこの問題を次のようにinnerHTMLを置き換えることで解決しました:
protected void SubmitMessages()
{
string[] lines = MessagesTextbox.Text.Split(new string[] { Environment.NewLine }, StringSplitOptions.None);
string output = "<ul>";
foreach (string message in lines)
{
if (!message.Equals(""))
{
output += "<li>";
output += message;
output += "</li>";
}
}
output += "</ul>";
messagesDiv.InnerHtml = output;
//string messagesFileLocation = AppDomain.CurrentDomain.BaseDirectory + "/mesages.xls";
string messagesFileLocation = "D:\\WebApp\\messages.xml";
FileStream fs = File.Open(messagesFileLocation, FileMode.Create, FileAccess.Write);
if (lines.Length != 0)
{
using (StreamWriter sw = new StreamWriter(fs))
{
sw.WriteLine("<Messages>");
foreach (string message in lines)
{
if (!message.Equals(""))
{
sw.WriteLine("\t<message>" + message + "</message>");
}
}
sw.WriteLine("</Messages>");
}
}
}