ค่าใน GridView จะให้มันทำงานในแถวๆนั้นต้องใช้คำสั่งยังไงเหรอครับ

Protected Sub TextBox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs)
	Dim senderTextBox As TextBox = TryCast(sender, TextBox)

	For i As Integer = 0 To GridView1.Rows.Count - 1
		Dim txtBox1 As TextBox = TryCast(GridView1.Rows(i).FindControl("TextBox1"), TextBox)

		If txtBox1.ClientID = senderTextBox.ClientID Then
			Dim txtBox2 As TextBox = TryCast(GridView1.Rows(i).FindControl("TextBox2"), TextBox)
			txtBox2.Text = "tungman"
		End If
	Next
End Sub