Since you are working in the ItemTemplate you don't really need to use Bind(). You can use Eval() instead and make something like:
<%# Eval("Address").ToString().Substring(0, 100) %>
There are two problems with such a simple solution:
The first is when the address field is null, you have to make a check of that. The second is if the string is shorter than 100 characters it will also fail since .NETs Substring() tries to ensure that you always get exactly 100 characters and throws an exception if the string is shorter. So you should add code to make sure that you really need to cut the string.
And by now it feels like maybe we should make a little helper method instead:
public static class Extensions
{
public static String Limit(this String s, int length)
{
if (s == null)
return String.Empty;
return s.Substring(0, Math.Min(s.Length, length));
}
}
Then the Eval statement will look like:
<%# ((string)Eval("Address")).Limit(100) %>
(This assumes that Address really is a string)