ต้องการเช็คค่าใน DataGridView ว่ามีค่าซ้ำกันรึเปล่าทำยังไงครับ

        Dim i As Integer = 0
        '================== เลือกสุนัขเเล้วส่งไปหน้า sale ====================
        For i = 0 To DataGridView1.Rows.Count - 1
            If DataGridView1.Rows(i).Selected Then
                Dim j As Integer = Sale.DataGridView2.Rows.Add()
                Sale.DataGridView2.Rows(j).Cells(0).Value = DataGridView1.Rows(i).Cells(0).Value
                Sale.DataGridView2.Rows(j).Cells(1).Value = DataGridView1.Rows(i).Cells(1).Value
                Sale.DataGridView2.Rows(j).Cells(2).Value = DataGridView1.Rows(i).Cells(2).Value
                Sale.DataGridView2.Rows(j).Cells(3).Value = DataGridView1.Rows(i).Cells(3).Value
                Sale.DataGridView2.Rows(j).Cells(4).Value = DataGridView1.Rows(i).Cells(4).Value
            End If
        Next

        Dim selectRow As Integer
        selectRow = Me.DataGridView1.CurrentRow.Index

        For i = 0 To DataGridView1.Rows.Count - 1
            DataGridView1.Rows().RemoveAt(selectRow)
        Next

foreach (System.Windows.Forms.DataGridViewRow dr in dataGridView1.SelectedRows)
 {
                dataGridView1.Rows.Remove(dr);
 }

Dim selectRow As Integer
selectRow = Me.DataGridView1.CurrentRow.Index

        For Each selectRow In DataGridView1.Rows()
            DataGridView1.Rows().RemoveAt(selectRow)
        Next

        Dim selectRow As Integer
        selectRow = Me.DataGridview1.CurrentRow.Index

        For i As Integer = 0 To DataGridview1.CurrentRow().Index
            DataGridview1.Rows().RemoveAt(selectRow)
        Next

For Each dgvr As System.Windows.Forms.DataGridViewRow In Me.DataGridView1.SelectedRows
            Me.DataGridView1.Rows.Remove(dgvr)
Next

Dim selectRow As Integer
selectRow = Me.DataGridview1.CurrentRow.Index
For i As Integer = 0 To DataGridview1.CurrentRow().Index
DataGridview1.Rows().RemoveAt(selectRow)
Next

 Private Sub DataGridView2_DoubleClick1(ByVal sender As Object, ByVal e As System.EventArgs) Handles DataGridView2.DoubleClick
        Dim selectRow As Integer
        Dim i As Integer
        Dim temp1 As Integer = 0
        Dim temp2 As Integer = 0
        Dim sum As Integer = 0
        selectRow = Me.DataGridView2.CurrentRow.Index
        If Me.DataGridView2.Rows.Count <> 0 Then
            If MessageBox.Show("ต้องการลบข้อมูลแถวนี้หรือไม่?", "Warning !!", MessageBoxButtons.YesNo, MessageBoxIcon.Question) = Windows.Forms.DialogResult.Yes Then
                For i = 0 To DataGridView2.Rows.Count - 1 'ให้วนตั้งเเต่เเถวเเรกจนถึงเเถวสุดท้าย
                    If DataGridView2.Rows(i).Selected Then 'เเถวไหนก็ตามที่มีการเลือกให้ทำเงื่อนไขด้านล่าง
                        temp1 = DataGridView2.Rows(i).Cells(4).Value
                        temp2 = lb_totalPrice.Text - temp1
                        sum = temp2
                        sum = FormatNumber(sum, 2)

                        Dim j As Integer = DataGridView2.Rows.Add()
                        Sale_DogList.DataGridView1.Rows(j).Cells(0).Value = DataGridView2.Rows(i).Cells(0).Value
                        Sale_DogList.DataGridView1.Rows(j).Cells(1).Value = DataGridView2.Rows(i).Cells(1).Value
                        Sale_DogList.DataGridView1.Rows(j).Cells(2).Value = DataGridView2.Rows(i).Cells(2).Value
                        Sale_DogList.DataGridView1.Rows(j).Cells(3).Value = DataGridView2.Rows(i).Cells(3).Value
                        Sale_DogList.DataGridView1.Rows(j).Cells(4).Value = DataGridView2.Rows(i).Cells(4).Value

                    End If
                Next

                Me.DataGridView2.Rows.RemoveAt(selectRow)
                lb_totalPrice.Text = sum.ToString("###,##0.00")
            End If
        End If

    End Sub

For Each dgvr As System.Windows.Forms.DataGridViewRow In Me.DataGridView2.SelectedRows
            Dim dgr As System.Windows.Forms.DataGridViewRow = dgvr.Clone()
            For i As Integer = 0 To dgvr.Cells.Count - 1
                dgr.Cells(i).Value = dgvr.Cells(i).Value
            Next
            DataGridView1.Rows.Add(dgr)
            Me.DataGridView2.Rows.Remove(dgvr)
Next

 Dim dgr As System.Windows.Forms.DataGridViewRow = dgvr.Clone()

        Dim i As Integer = 0
        For i = 0 To Sale.DataGridView2.Rows.Count - 1
            Dim temp_DogID As String = ""
            temp_DogID = Sale.DataGridView2.Rows(i).Cells(0).Value

            If temp_DogID = Me.DataGridView1.Rows(i).Cells(0).Value Then
                MessageBox.Show("ซ้ำกรุณาเลือกใหม่", "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning)
                Exit Sub
            End If
        Next

Dim i As Integer = 0
For i = 0 To Sale.DataGridView2.Rows.Count - 1
Dim temp_DogID As String = ""
temp_DogID = Sale.DataGridView2.Rows(i).Cells(0).Value
 
If temp_DogID = Me.DataGridView1.CurrentRow.Cells(0).Value Then ' ใช้ CurrentRow เพื่อเอาค่าที่เราเลือก ณ ตอนนั้นไปเทียบกับ Grid ที่เราจะใส่ข้อมูล
     MessageBox.Show("ซ้ำกรุณาเลือกใหม่", "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning)
      Exit Sub
   End If
Next

For Each dgvr As System.Windows.Forms.DataGridViewRow In Me.DataGridView2.SelectedRows 'บอกว่า loop ทุกๆ ค่า rows ที่เลือกไว้
Dim dgr As System.Windows.Forms.DataGridViewRow = dgvr.Clone() 'ให้ทำการ clone structure ของ row นี้ไว้ นั่นคือ ได้ columes ของ datagridview นี้ไว้ แต่ไม่ได้ values นะ
            For i As Integer = 0 To dgvr.Cells.Count - 1
                dgr.Cells(i).Value = dgvr.Cells(i).Value
            Next 'loop นี้บอกว่า ให้ copy ค่าของทุกๆ cells ใน dgvr เข้าทุกๆ cells ของ dgr อันนี้จะได้ values แล้ว
            DataGridView1.Rows.Add(dgr)' เพิ่ม rows ใหม่ใน datagridview1 นั่นก็คือ grid ของน้องที่อยากให้เอาค่าไปลงแหล่ะครับ
            Me.DataGridView2.Rows.Remove(dgvr)'ลบ rows เก่าที่น้อง double click แหล่ะครับ
Next

    Private Sub btnSelectDog_Click(sender As Object, e As EventArgs) Handles btnSelectDog.Click
        Dim f As New frmDataGridView2
        f.strDogCode = If(DataGridView1.SelectedRows.Count > 0 AndAlso DataGridView1.Columns.Count > 0, DataGridView1.SelectedRows(0).Cells("IDCardNo").Value, String.Empty)
        f.srcDataGridView = DataGridView1
        f.ShowDialog()
    End Sub

Public Class frmDataGridView2
    Public strDogCode As String = String.Empty 'รหัสสุนัข
    Public srcDataGridView As DataGridView = Nothing ' DataGridView1 control in frmDataGridView1
    Public strDogCodeReturnValue As String = String.Empty

    Private Sub frmDataGridView2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'เลือกระเบียนถ้าจำเป็น แต่ยังไม่ขออึ๊บ
        RemoveHandler DataGridView2.SelectionChanged, AddressOf DataGridView2_SelectionChanged
        DataGridView2.ClearSelection()
        'Fill Data when you down.
        DataGridView2.Rows.Add("1", "111")
        DataGridView2.Rows.Add("2", "222")
        DataGridView2.Rows.Add("3", "333")
        DataGridView2.Rows.Add("4", "444")
        If Not String.IsNullOrEmpty(strDogCode) Then
            Dim tmpSelectedRow = (From r As DataGridViewRow In DataGridView2.Rows
                                  Where r.Cells("IDCardNo").Value = strDogCode).FirstOrDefault()
            If tmpSelectedRow IsNot Nothing AndAlso DataGridView2.Columns.Count > 0 Then
                DataGridView2.CurrentCell = DataGridView2.Rows(tmpSelectedRow.Index).Cells(0)
            End If
        End If
        AddHandler DataGridView2.SelectionChanged, AddressOf DataGridView2_SelectionChanged
    End Sub
    Private Sub DataGridView2_SelectionChanged(sender As Object, e As EventArgs) Handles DataGridView2.SelectionChanged
        MessageBox.Show("ขออึ๊บได้ไหม?")
        strDogCodeReturnValue = String.Empty
        If srcDataGridView IsNot Nothing AndAlso DataGridView2.SelectedRows.Count > 0 Then
            If Not DataGridView2.SelectedRows(0).Cells("IDCardNo").Value <> strDogCode Then
                Dim lstDup = (From r As DataGridViewRow In srcDataGridView.Rows Where (Not r.IsNewRow AndAlso r.Cells("IDCardNo").Value = DataGridView2.SelectedRows(0).Cells("IDCardNo").Value)
                              Group r By key = r.Cells("IDCardNo").Value Into tmpGrp = Group
                              Where tmpGrp.Count() > 0
                              Select IDCardNO = key, cntIDCardNo = tmpGrp.Count()).ToList()

                If lstDup IsNot Nothing AndAlso lstDup.Count > 0 Then
                    lstDup.ForEach(Sub(x)
                                       MessageBox.Show(x.IDCardNO & " นับได้ " & x.cntIDCardNo)
                                   End Sub)
                Else
                    strDogCodeReturnValue = DataGridView2.SelectedRows(0).Cells("IDCardNo").Value
                End If
            End If
        End If
    End Sub
End Class