How to best deal with a cross site scripting threat

I have security audit scan that is flagging line 4 below
"The method DisplayCustomMessage() in clientSummary.cs sends unvalidated data to a web browser on line 4 which can result in the browser executing malicious code."

This appears to be a cross site scripting vulnerability. So how can I correct this code?

1.  private void DisplayCustomMessage(string msg)
2.  {
3.      lblMsg.CssClass = "pling";
4.      lblMsg.Text = msg
5.      lblMsg.Visible = true
6.
7.}
LVL 2
brgdotnetcontractorAsked:
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MlandaTCommented:
LblMsg.Text = HttpUtility.HtmlEncode(msg)

You need to encode your msg before inserting it into your label. It's the thing with not trusting user input to your function.

https://msdn.microsoft.com/en-us/library/73z22y6h(v=vs.110).asp.net for further details.
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brgdotnetcontractorAuthor Commented:
Thank you.
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