Why Can't I store XML in ASP.NET ListBox Value?

Question

Hello,

Why does this work:

ListItem item = new ListItem();
string value = lstAvailExtPropsToFilter.SelectedItem.Text +" = "+ txtExtPropToFilter.Text;
string text = lstAvailExtPropsToFilter.SelectedItem.Text + " = " + txtExtPropToFilter.Text;
item.Text = text;
item.Value = value;
lstExtPropsToFilter.Items.Add(item);

But not this:

ListItem item = new ListItem();
string value = string.Format("<key>{0}</key><value>{1}</value>", lstAvailExtPropsToFilter.SelectedItem.Text, txtExtPropToFilter.Text);
string text = lstAvailExtPropsToFilter.SelectedItem.Text + " = " + txtExtPropToFilter.Text;
item.Text = text;
item.Value = value;
lstExtPropsToFilter.Items.Add(item);

Answer 1

You would have to escape the string so it works in HTML. Try Server.HTMLEncode.

Server.HTMLEncode("<key>{0}</key><value>{1}</value>")

Then when you need to pull the value you, use Server.HTMLDecode.