Datagridview Search

I am using a datagridview that I populate from the local machine's Outlook contacts. I am not currently using a dataset or table but populating the data directly from Outlook. This is all working fine. The datagridview contains a checkbox that I'll use to loop and perform some action with all the selected rows. My challenge is to add some intelligent search options to type a value into a text box and search the grid. If I do not get the right 'John' I would like to continue the search and move to the next 'John'
I got the first part working to some extend but need some help.
Current search Code snippet included under code

Dim x As Integer = 0
        While x < DataGridView1.Rows.Count
            Dim y As Integer = 0
            While y < DataGridView1.Rows(x).Cells.Count
                Dim c As DataGridViewCell = DataGridView1.Rows(x).Cells(y)
                If CType(c.Value, String) Is Nothing Then
                Else
                    If InStr(UCase(CType(c.Value, String)), UCase(TextBox2.Text)) Then
                        DataGridView1.Rows(x).Selected = True
                        DataGridView1.CurrentCell = DataGridView1.Rows(x).Cells(y)

                    End If
                End If
                System.Math.Min(System.Threading.Interlocked.Increment(y), y - 1)
            End While
            System.Math.Min(System.Threading.Interlocked.Increment(x), x - 1)
        End While

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