Hi,
You can use a common column alias name for sql queries and use that alias column name for data bind. Like try this code below,
in *.aspx
<asp:TextBox Text='<%#Eval("mycolumn") %>'/>
in *.aspx.cs
SqlDataAdapter dt = new SqlDataAdapter("select col1 as mycolumn from Table1", Con);
SqlDataAdapter dt = new SqlDataAdapter("select col2 as mycolumn from Table1", Con);
as you can see both queries use same column alias, so switching data source for GridView wont effect the binding.
Hope this will help.