Problem In Saving Page Contents I.e; Textbox And Dropdownlist Values Please Help

Hi all,

please have a look of code i am unable to perform save operation on
the asp.net web page.
I ahve written a stored procedure. the same code works if all are
textboxes, but some of textbox replaced with dropdownlist box then
this save operation doesn't occurs. please let me know where is the
mistake in coding .

vb.net code :-

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

        Dim employmentID As Integer =
Request.QueryString("employmentID")
        Dim resourceID As Integer = Request.QueryString("resourceID")
        Dim projectID As Integer = Request.QueryString("ProjectID")
        Dim dbconsave As SqlConnection
        dbconsave = New SqlConnection(HRISDBConnectionString)
        Dim dbcomsave As New SqlCommand("sp_save_NewHireEmailnotify",
dbconsave)
        dbcomsave.CommandType = CommandType.StoredProcedure
        dbcomsave.Parameters.Add(New SqlParameter("employmentID",
SqlDbType.Int))
        dbcomsave.Parameters("employmentID").Value = employmentID
        dbcomsave.Parameters.Add(New SqlParameter("resourceID",
SqlDbType.Int))
        dbcomsave.Parameters("resourceID").Value = resourceID
        dbcomsave.Parameters.Add(New SqlParameter("ProjectID",
SqlDbType.Int))
        dbcomsave.Parameters("ProjectID").Value = projectID
        dbconsave.Open()
        dbcomsave.Parameters.Add("@PreferredFirstName",
SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@PreferredFirstName").Value =
txtPreferredFirstName.Text.ToString()
        dbcomsave.Parameters.Add("@PreferredLastName",
SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@PreferredLastName").Value =
txtPreferredLastName.Text.ToString()
        dbcomsave.Parameters.Add("@CellPhone", SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@CellPhone").Value =
txtCellPhone.Text.ToString()
        dbcomsave.Parameters.Add("@HomePhone", SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@HomePhone").Value =
txtHomePhone.Text.ToString()
        dbcomsave.Parameters.Add("@HomeAddressLine1",
SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@HomeAddressLine1").Value =
txtHomeAddressLine1.Text.ToString()
        dbcomsave.Parameters.Add("@HomeAddressLine2",
SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@HomeAddressLine2").Value =
txtHomeAddressLine2.Text.ToString()
        dbcomsave.Parameters.Add("@HomeAddressState",
SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@HomeAddressState").Value =
txtHomeAddressState.Text.ToString()
        dbcomsave.Parameters.Add("@HomeAddressCity",
SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@HomeAddressCity").Value =
txtHomeAddressCity.Text.ToString()
        dbcomsave.Parameters.Add("@HomeAddressZIP", SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@HomeAddressZIP").Value =
txtHomeAddressZIP.Text.ToString()
        dbcomsave.Parameters.Add("@HomeAddressCountry",
SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@HomeAddressCountry").Value =
txtHomeAddressCountry.Text.ToString()
        dbcomsave.Parameters.Add("@ArrangementType",
SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@ArrangementType").Value =
ddlArrangementType.SelectedItem.ToString()
        dbcomsave.Parameters.Add("@PracticeGroup", SqlDbType.VarChar)
        dbcomsave.Parameters.Item("@PracticeGroup").Value =
ddlPracticeGroup.SelectedItem.ToString()
        dbcomsave.Parameters.AddWithValue("@EquipmentNeeds",
txtEquipmentNeeds.Text.ToString())

        Try
            dbcomsave.ExecuteNonQuery()
            lblMessage.Text = "Record saved successfully"
        Catch ex As Exception

        End Try
        dbconsave.Close()
    End Sub

==============================================================================

.aspx code :-

<table>
                                 <tr>
                                    <td >
                                        <asp:Label
ID="lblPreferredFirstName" runat="server" Text="Name(Preferred First
Last) :" ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td

                                        <asp:TextBox
ID="txtPreferredFirstName" runat="server" Text="" BorderStyle="None"
></asp:TextBox>&nbsp;&nbsp;

                                        <asp:TextBox
ID="txtPreferredLastName" runat="server" Text="" BorderStyle="none" ></
asp:TextBox>
                                    </td>
                                </tr>
                <tr>
                                    <td >
                                        <asp:Label ID="lblCellPhone"
runat="server" Text="CellPhone :" ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td >
                                        <asp:TextBox ID="txtCellPhone"
runat="server" Text="" ></
asp:TextBox>
                                    </
td>
                                </tr>
                <tr>
                                    <td >
                                        <asp:Label ID="lblHomePhone"
runat="server" Text="HomePhone :" ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td >
                                        <asp:TextBox ID="txtHomePhone"
runat="server" Text="" ></
asp:TextBox>
                                    </
td>
                                </tr>
                <tr>
                                    <td >
                                        <asp:Label
ID="lblHomeAddressLine1" runat="server" Text="HomeAddressLine1 :"
ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td >
                                        <asp:TextBox
ID="txtHomeAddressLine1" runat="server" Text="" ></asp:TextBox>
                                    </
td>
                                </tr>
                                <tr>
                                    <td >
                                        <asp:Label
ID="lblHomeAddressLine2" runat="server" Text="HomeAddressLine2 :"
ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td >
                                        <asp:TextBox
ID="txtHomeAddressLine2" runat="server" Text="" ></asp:TextBox>
                                    </
td>
                                </tr>
                                <tr>
                                    <td >
                                        <asp:Label
ID="lblHomeAddressState" runat="server" Text="HomeAddressState :"
ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td >
                                        <asp:TextBox
ID="txtHomeAddressState" runat="server" Text="" ></asp:TextBox>
                                    </
td>
                                </tr>
                                <tr>
                                    <td >
                                        <asp:Label
ID="lblHomeAddressCity" runat="server" Text="HomeAddressCity :"
ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td >
                                        <asp:TextBox
ID="txtHomeAddressCity" runat="server" Text="" ></asp:TextBox>
                                    </
td>
                                </tr>
                                <tr>
                                    <td >
                                        <asp:Label
ID="lblHomeAddressZIP" runat="server" Text="HomeAddressZIP :"
ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td >
                                        <asp:TextBox
ID="txtHomeAddressZIP" runat="server" Text="" ></asp:TextBox>
                                    </
td>
                                </tr>
                                <tr>
                                    <td >
                                        <asp:Label
ID="lblHomeAddressCountry" runat="server" Text="HomeAddressCountry :"
ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td >
                                        <asp:TextBox
ID="txtHomeAddressCountry" runat="server" Text="" ></asp:TextBox>
                                    </
td>
                                </tr>
                <tr>
                                    <td >
                                        <asp:Label ID="lblArrangement"
runat="server" Text="Arrangement :" ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td >
                                        <asp:DropDownList
ID="ddlArrangementType" runat="server" Width="160px"
DataSourceID="ObjectDataSourceArrangementType"

DataTextField="ArrangementType" DataValueField="ArrangementType"
OnDataBound="ddlArrangementType_DataBound">
                                        </
asp:DropDownList>
                                        <%--<asp:TextBox
ID="txtArrangement" runat="server" Text="" ></asp:TextBox>--%>
                                    </
td>
                                </tr>
                 <tr>
                                    <td >
                                        <asp:Label
ID="lblPracticeGroup" runat="server" Text="Practice Group :"
ForeColor="Blue"></asp:Label>
                                    </td>
                                    <td >
                                        <asp:DropDownList
ID="ddlPracticeGroup" runat="server" Width="160px"
DataSourceID="ObjectDataSourcePracticeGroup"

DataTextField="PracticeGroup" DataValueField="PracticeGroup"
OnDataBound="ddlPracticeGroup_DataBound">
                                        </
asp:DropDownList>
                                        <%--<asp:TextBox
ID="txtPracticeGroup" runat="server" Text="" ></asp:TextBox> --
%>

                                    </
td>
                                </tr></table>

please help me to solve the issue.

Thanks in advance