The solution is to define the following property in the column you want there to be line break:
ItemStyle-Wrap="True"
Or simply don’t put any property. The default of GridView Asp.NET is to break. If you want nay there is break, then add the same property but with the value false. Thus, the HTML generated for the column (<td>) will come with the property style="white-space:nowrap;".
Observing: From the image of your test there will never be a break because you have included a single word with hundreds of characters ("AAAAAAAAA...."). Try testing with long text, but with words of varying sizes and consistent with words that exist.
put your grid code.
– Marco Souza