how can i set an unbound GridView column to invisible in code

 Dim Application = From AL In db.AnnualLeave _
                    Where AL.Approval <> True _
                    Select LeaveID, EmpID, Name

    GridView3.DataSource = Application
    GridView3.DataBind()

after calling `GridView3.DataBind()开发者_StackOverflow社区, why do i still get

Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index.

at this line of code GridView3.Columns(1).Visible = False yet the grid has rows and more than 2 columns. i found a thread about similar problem here http://forums.asp.net/t/1025678.aspx/1

Note that the Gridview columns have NOT been defined at design time. `

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You need to be careful where you place your code in asp.net. If you placed that GridView3.Columns(1).Visible = False code in the wrong place at the wrong time then yes, it would throw an error.

I suggest reading up on ASP.NET Page Lifecyle