“Cannot change ReadOnly property of the expression column”, has been a known bug since 2002 in the .net framework.

Basically when you use an insert and update with your column you will have this error. An easy work around is to simply copy the content from a non expression column and manipulate the data row by row.

This example creates a hyperlink from table data, removing spaces and adding a page suffix.

Dim row As DataRow
For Each row In myDataSet.Tables("DT1").Rows
row("C2") = row("C1").ToString.Replace(" ", "-")
row("C2") = row("C2").ToString + "-page.aspx"
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