Attach A String To A Label Control

How do I attach a string to a label control. This is what I have so far:

<asp:Label
ID="Label1"
runat="server"
/>

and in the code behind I have the following:

protected void Page_PreLoad(object sender, EventArgs e)
{
if (!IsPostBack)
{
ViewState["string1"] = new System.Text.StringBuilder();
}
}
protected void Page_Load(object sender, EventArgs e)
{
System.Text.StringBuilder string1 = (System.Text.StringBuilder)ViewState["string1"];
string1.Append("This has been appended to string1.");
}

But how do I connect my string to my label?

I'm writing in c# and using Visual Web Developer Express 2008