Edit and update my SQL Server database with the edit and update - asp.net

Question

I have a SQL Server table with 5 columns. col1 is the primary key. I an working in ASP.net 4.0.
I want to be able to edit and update my SQL Server table with the edit and update respectively.
I am having a little trouble with the update. Here is my code:
<asp:GridView ID="GridView1" runat="server" AutoPostBack="True" AutoGenerateColumns="True" AutoGenerateEditButton="True" OnRowEditing="Gridview1_OnRowEditing" OnRowUpdating="GridView1_OnRowUpdating">
</asp:GridView>
Code:
Sub ShowGrid()
Dim connStr, cmdStr As String
connStr = "connection string works"
cmdStr = "SELECT * FROM table1;"
Dim MyDataSet As New DataSet
Dim MyDataTable As New DataTable()
Try
Using conn As New SqlConnection(connStr)
Using cmd As New SqlCommand(cmdStr, conn)
conn.Open()
cmd.ExecuteNonQuery()
Using MyDataAdaptor As New SqlDataAdapter(cmd)
MyDataAdaptor.Fill(MyDataSet)
MyDataTable = MyDataSet.Tables(0)
GridView1.EditIndex = Convert.ToInt32(ViewState("edit"))
GridView1.DataSource = MyDataTable
GridView1.DataBind()
End Using
conn.Close()
cmd.Dispose()
conn.Dispose()
End Using
End Using
Catch ex As Exception
Throw ex
End Try
End Sub
Protected Sub GridView1_OnRowEditing(ByVal sender As Object, ByVal e As GridViewEditEventArgs)
GridView1.EditIndex = e.NewEditIndex
ViewState("edit") = GridView1.EditIndex
ShowGrid()
End Sub
Protected Sub GridView1_OnRowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs)
Dim connStr, cmdStr As String
connStr = "connection string works"
cmdStr = "UPDATE table1 SET (col2=#col2,col3=#col3,col4=#col4,col5=#col5) WHERE col1=#col1;"
Try
Using conn As New SqlConnection(connStr)
Using cmd As New SqlCommand(cmdStr, conn)
conn.Open()
cmd.Parameters.AddWithValue("#col1", GridView1.Rows(e.RowIndex).Cells(0).Text)
cmd.Parameters.AddWithValue("#col2", GridView1.Rows(e.RowIndex).Cells(1).Text)
cmd.Parameters.AddWithValue("#col3", GridView1.Rows(e.RowIndex).Cells(2).Text)
cmd.Parameters.AddWithValue("#col4", GridView1.Rows(e.RowIndex).Cells(3).Text)
cmd.Parameters.AddWithValue("#col5", GridView1.Rows(e.RowIndex).Cells(4).Text)
cmd.ExecuteNonQuery()
conn.Close()
cmd.Dispose()
conn.Dispose()
End Using
End Using
Catch ex As Exception
End Try
ViewState("edit") = e.RowIndex
ShowGrid()
End Sub