try like this
place a div tag in item template and inside the div tag put your message column and give fixed width for div
ex
<asp: xmlns:asp="#unknown">
GridView ID="GridView2" runat="server" AutoGenerateColumns="False"
<Columns>
<asp:templatefield headertext="Name" headerstyle-font-size="Medium" headerstyle-width="150px" headerstyle-font-names="Microsoft Sans Serif">
<itemtemplate>
<div style="width :150px;font-size :medium ;font-family :Microsoft Sans Serif ">
<asp:label id="lblID" runat="server" text="<%# DataBinder.Eval(Container.DataItem,"Name") %>"></asp:label>
</div>
</itemtemplate>
</asp:templatefield>