GridView button with condition

I have a gridview with 3 columns Name,Surname,Change(ButtonField column) which is populated from an SqlDataReader with the following code

SqlCommand sqlCommand = new SqlCommand("select * from Empl where userId ='" + userid + "'", sqlConnection);
sqlConnection.Open();

SqlDataReader reader = sqlCommand.ExecuteReader();

GridView1.DataSource = reader;
GridView1.DataBind();

In my database there are 4 columns UserId,Name,Surname,Change(bit). How can i show the button change only when Change(bit) column is true inside the database?

Hi pikkas...

I have never done it... but I did find an msdn article describing a way to do this if that helps...

http://msdn.microsoft.com/en-us/library/ms171619.aspx