Invalid postback argument when GridView1_RowCommand fired

Imports System.Data.SqlClient

Public Class listview

    Inherits System.Web.UI.Page

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

        'Response.Write("value loop " & gvwExample.PageIndex & "
")

        

        Dim cmd As SqlCommand = New SqlCommand("SELECT  UserName,pass_word,ApplicantName,FatherName FROM userinfo", New SqlConnection(" Server=vu-it-wqs-pc\sqlexpress;Database=Test;Uid=sa;Pwd=123;"))

        Try

            Dim adp As New SqlDataAdapter(cmd)

            cmd.Connection.Open()

            Dim ds As New DataSet()

            adp.Fill(ds)

            gvwExample.DataSource = ds

            cmd.ExecuteReader()

            gvwExample.DataBind()

            adp.Dispose()

            ds.Dispose()

            cmd.Connection.Dispose()

        Catch ex As Exception

            lblStatus.Text = ex.Message

       

        End Try

    End Sub

    Protected Sub OnPaging(ByVal sender As Object, ByVal e As GridViewPageEventArgs) Handles gvwExample.PageIndexChanging

        Try

            gvwExample.PageIndex = e.NewPageIndex

            gvwExample.AllowPaging = True

            gvwExample.DataBind()

        Catch ex As Exception

            lblStatus.Text = ex.Message

        End Try

    End Sub

    Protected Sub GridView1_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs)

        Response.Redirect("DBform.aspx")

        lblStatus.Text = "dddd"

        If Not (IsPostBack) Then

            lblStatus.Text = "dddd1"

            If (e.CommandName = "Delete") Then

                ' Retrieve the row index stored in the CommandArgument property.

                Dim index As Integer = Convert.ToInt32(e.CommandArgument)

                lblStatus.Text = "dddd2"

                ' Retrieve the row that contains the button 

                ' from the Rows collection.

                Dim row As GridViewRow = gvwExample.Rows(index)

                Response.Write("value loop " + index + "
")

                ' Add code here to add the item to the shopping cart.

            End If

        End If

    End Sub

    'Protected Sub gvwExample_SelectedIndexChanged(sender As Object, e As EventArgs) Handles gvwExample.SelectedIndexChanged

    '    If Not (IsPostBack) Then

    '        'If (e.CommandName = "Delete") Then

    '        '    ' Retrieve the row index stored in the CommandArgument property.

    '        '    Dim index As Integer = Convert.ToInt32(e.CommandArgument)

    '        '    ' Retrieve the row that contains the button 

    '        '    ' from the Rows collection.

    '        '    Dim row As GridViewRow = gvwExample.Rows(index)

    '        Response.Write("value loop 55" & gvwExample.PageIndex & "
")

    '        ' Add code here to add the item to the shopping cart.

    '        'End If

    '    End If

    'End Sub

End Class






aspx code