Datagrid / update command

I have a datagrid that pulls in the information. I have a Edit button that works fine. When I go to edit a row, and click the Update button, I get an error saying:
Object reference not set to an instance of an object.

The code breaks on the
dname = CType(e.Item.FindControl("txtDeceasedName"), TextBox).Text line.

VB Code:

'Retrieve the data from the DataGrid
        Dim mID As Integer
        Dim dname As String
        Dim relatedto As String
        Dim relationship As String
        Dim dateofdeath As Date
        Dim notes As String
        Dim visitation As String
        Dim funeral As String
 
        mID = dgMemoriam.DataKeys(e.Item.ItemIndex)
        dname = CType(e.Item.FindControl("txtDeceasedName"), TextBox).Text
        relatedto = CType(e.Item.FindControl("txtRelatedTo"), TextBox).Text
        relationship = CType(e.Item.FindControl("txtRelationship"), TextBox).Text
        dateofdeath = CType(e.Item.FindControl("txtDateofDeath"), TextBox).Text
        notes = CType(e.Item.FindControl("txtNotes"), TextBox).Text
        visitation = CType(e.Item.FindControl("txtVisitation"), TextBox).Text
        funeral = CType(e.Item.FindControl("txtFuneral"), TextBox).Text