gridview 单元格为空时，加亮提示

 如果是objectDataSource

If e.Row.DataItem IsNot Nothing Then
            Dim uservo As userVO = CType(e.Row.DataItem, userVO)
            If uservo.Email.Equals("") Then
                e.Row.Cells(3).BackColor = Color.Red
                e.Row.Cells(3).Text = "空"
                e.Row.Cells(3).ForeColor = Color.White
            End If
        End If

如果是sqlDataSource

If e.Row.DataItem IsNot Nothing Then
            Dim drv As DataRowView = CType(e.Row.DataItem, DataRowView)
            If drv("Email") Is System.DBNull.Value Then
                e.Row.Cells(3).BackColor = Color.Red
                e.Row.Cells(3).Text = "空"
                e.Row.Cells(3).ForeColor = Color.White
            End If
        End If