Cant't Update SQL Server Table in VB.NET

Question

Using Visual Studio 2002 and Microsoft SQL Server. My code does not produce an error, but still the SQL Server table is is still unaffected. :(

The "Add" version of this code works well. . it's just the update. T_T

    Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click

    Try
        ''Open DBase
        dbOpen()
        Dim cmd As New SqlCommand()
        Dim cmdm As New SqlCommand()

        cmd.CommandText = "UPDATE [Currency] SET Country= @Country, Unit= @Unit , Code= @Code WHERE ISO= @ISO"

        Dim paramISO As New SqlParameter()
        paramISO.ParameterName() = "@ISO"
        paramISO.Value() = txtIso.Text
        cmd.Parameters.Add(paramISO)

        Dim paramCountry As New SqlParameter()
        paramCountry.ParameterName() = "@Country"
        paramCountry.Value() = txtCountry.Text
        cmd.Parameters.Add(paramCountry)

        Dim paramUnit As New SqlParameter()
        paramUnit.ParameterName() = "@Unit"
        paramUnit.Value() = txtUnit.Text
        cmd.Parameters.Add(paramUnit)

        Dim paramCode As New SqlParameter()
        paramCode.ParameterName() = "@Code"
        paramCode.Value() = txtCurrencyCode.Text
        cmd.Parameters.Add(paramCode)

        MessageBox.Show("Record Updated! ", "Update Status", MessageBoxButtons.OK, MessageBoxIcon.Information)

    Catch ex As Exception
        MessageBox.Show("Record Not Updated! ", "Update Status", MessageBoxButtons.OK, MessageBoxIcon.Information)
    Finally
        dbClose()
        'refresh data grid
        fillgrid()
        'disable fields
        disControl()
    End Try
End Sub

Answer 1

You're missing this statement:

cmd.ExecuteNonQuery()  

Add this statement after you've done adding all the parameters to your sqlCommand object.