Preventing blank row insert into sqlserver from a gridview in asp.net

Dim conn As SqlConnection = 

New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString.ToString())

    'Dim conn As SqlConnection = 

New SqlConnection(ConfigurationManager.ConnectionStrings("ConStr").ConnectionString.ToString())

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        If Not Page.IsPostBack Then

            SetInitialRow()

        End If

    End Sub

    Private Sub SetInitialRow()

        Dim dt As New DataTable()

        Dim dr As DataRow = Nothing

        dt.Columns.Add(New DataColumn("RowNumber", GetType(String)))

        dt.Columns.Add(New DataColumn("Column1", GetType(String)))

        dt.Columns.Add(New DataColumn("Column2", GetType(String)))

        dt.Columns.Add(New DataColumn("Column3", GetType(String)))

        dt.Columns.Add(New DataColumn("Column4", GetType(String)))

        dt.Columns.Add(New DataColumn("Column5", GetType(String)))

        dr = dt.NewRow()

        dr("RowNumber") = 1

        dr("Column1") = String.Empty

        dr("Column2") = String.Empty

        dr("Column3") = String.Empty

        dr("Column4") = String.Empty

        dr("Column5") = String.Empty

        dt.Rows.Add(dr)

        'Store the DataTable in ViewState

        ViewState("CurrentTable") = dt

        Gridview1.DataSource = dt

        Gridview1.DataBind()

    End Sub

    Private Sub SetPreviousData()

    Dim rowIndex As Integer = 0

    If ViewState("CurrentTable") IsNot Nothing Then

     Dim dt As DataTable = DirectCast(ViewState("CurrentTable"), DataTable)

     If dt.Rows.Count > 0 Then

     For i As Integer = 1 To dt.Rows.Count - 1

Dim box1 As TextBox = 

DirectCast(Gridview1.Rows(rowIndex).Cells(1).FindControl("txt_ITEMCODE"), TextBox)

Dim box2 As TextBox =  

DirectCast(Gridview1.Rows(rowIndex).Cells(2).FindControl("txt_NAME"), TextBox)

Dim box3 As TextBox = 

DirectCast(Gridview1.Rows(rowIndex).Cells(3).FindControl("txt_QTY"), TextBox)

Dim box4 As TextBox =

 DirectCast(Gridview1.Rows(rowIndex).Cells(4).FindControl("txt_RATE"), TextBox)

Dim box5 As TextBox = 

DirectCast(Gridview1.Rows(rowIndex).Cells(5).FindControl("txt_AMNT"), TextBox)

    box1.Text = dt.Rows(i)("Column1").ToString()

    box2.Text = dt.Rows(i)("Column2").ToString()

    box3.Text = dt.Rows(i)("Column3").ToString()

    box4.Text = dt.Rows(i)("Column4").ToString()

    box5.Text = dt.Rows(i)("Column5").ToString()

   box5.Text = Convert.ToString(Convert.ToInt32(box3.Text) * Convert.ToInt32(box4.Text))

    rowIndex += 1

    Next

  End If

End If

End Sub

Private Sub AddNewRowToGrid()

Dim rowIndex As Integer = 0

If ViewState("CurrentTable") IsNot Nothing Then

Dim dtCurrentTable As DataTable = DirectCast(ViewState("CurrentTable"), DataTable)

Dim drCurrentRow As DataRow = Nothing

If dtCurrentTable.Rows.Count > 0 Then

For i As Integer = 1 To dtCurrentTable.Rows.Count

'extract the TextBox values

Dim box1 As TextBox =

 DirectCast(Gridview1.Rows(rowIndex).Cells(1).FindControl("txt_ITEMCODE"), TextBox)

Dim box2 As TextBox =

 DirectCast(Gridview1.Rows(rowIndex).Cells(2).FindControl("txt_NAME"), TextBox)

Dim box3 As TextBox =

 DirectCast(Gridview1.Rows(rowIndex).Cells(3).FindControl("txt_QTY"), TextBox)

Dim box4 As TextBox =

 DirectCast(Gridview1.Rows(rowIndex).Cells(4).FindControl("txt_RATE"), TextBox)

Dim box5 As TextBox =

 DirectCast(Gridview1.Rows(rowIndex).Cells(5).FindControl("txt_AMNT"), TextBox)

                    drCurrentRow = dtCurrentTable.NewRow()

                    drCurrentRow("RowNumber") = i + 1

                    drCurrentRow("Column1") = box1.Text

                    drCurrentRow("Column2") = box2.Text

                    drCurrentRow("Column3") = box3.Text

                    drCurrentRow("Column4") = box4.Text

                    drCurrentRow("Column5") = box5.Text

                    rowIndex += 1

                Next

                'add new row to DataTable

                dtCurrentTable.Rows.Add(drCurrentRow)

                'Store the current data to ViewState

                ViewState("CurrentTable") = dtCurrentTable

                'Rebind the Grid with the current data

                Gridview1.DataSource = dtCurrentTable

                Gridview1.DataBind()

            End If

        Else

            Response.Write("ViewState is null")

        End If

        'Set Previous Data on Postbacks

        SetPreviousData()

    End Sub

    Protected Sub ButtonAdd_Click(ByVal sender As Object, ByVal e As EventArgs)

        AddNewRowToGrid()

    End Sub

    Protected Sub InsertAll_Click(ByVal sender As Object, ByVal e As EventArgs)

        conn.Open()

        Dim query As String = "INSERT INTO TRN_MAST(TRN_NO,TRN_DT,REMARKS)

 VALUES (@TRN_NO,@TRN_DT,@REMARKS)"

        Dim cmd As New SqlCommand(query, conn)

        cmd.Parameters.AddWithValue("@TRN_NO", txtTrnNo.Text)

        cmd.Parameters.AddWithValue("@TRN_DT", txtTrnDt.Text)

        cmd.Parameters.AddWithValue("@REMARKS", txtRemarks.Text)

        cmd.ExecuteNonQuery()

        conn.Close()

        Response.Write(Gridview1.Rows.Count)

        conn.Open()

        For i As Integer = 0 To Gridview1.Rows.Count - 1

            Dim str As String = "INSERT INTO DTL_MAST(TRN_NO,ITEM_CODE,NAME,QTY,

RATE,AMNT) VALUES (@TRN_NO,@ITEM_CODE,@NAME,@QTY,@RATE,@AMNT)"

            Dim cmdInsertAll As New SqlCommand(str, conn)

cmdInsertAll.Parameters.AddWithValue("@TRN_NO", txtTrnNo.Text)

cmdInsertAll.Parameters.AddWithValue("@ITEM_CODE", DirectCast(Gridview1.Rows(i).FindControl("txt_ITEMCODE"), TextBox).Text)

cmdInsertAll.Parameters.AddWithValue("@NAME", DirectCast(Gridview1.Rows(i).FindControl("txt_NAME"), TextBox).Text)

cmdInsertAll.Parameters.AddWithValue("@QTY", DirectCast(Gridview1.Rows(i).FindControl("txt_QTY"), TextBox).Text)

cmdInsertAll.Parameters.AddWithValue("@RATE", DirectCast(Gridview1.Rows(i).FindControl("txt_RATE"), TextBox).Text)

cmdInsertAll.Parameters.AddWithValue("@AMNT", DirectCast(Gridview1.Rows(i).FindControl("txt_AMNT"), TextBox).Text)

            cmdInsertAll.ExecuteNonQuery()

        Next

        conn.Close()

        Response.Write("<Script>alert(' Record inserted')</script>")

        'lblMsg.Text = "Data inserted...";

    End Sub