Having difficulty populating a DropDownList within a GridView - asp.net

Question

As the title states I am having a lot of difficulty populating a drop down list that is within a gridview on my web form. I feel like this process should be relatively straight forward as I have populated many gridviews and drop down lists in the past without a hitch. Below, I have detailed what I have tried and will post any associated code. I am relatively new to software development and any help in solving this problem would be greatly appreciated.
To start I have added a drop down list to the gridview in question. Code below.
<asp:GridView ID="GridView3" runat="server"
EmptyDataText="No Claimed Parts" AutoGenerateColumns="False"
ShowHeaderWhenEmpty="True" DataKeyNames="RecID"
ShowFooter="True" DataSourceID="SqlDataSource5" Width="95%">
<EmptyDataTemplate>
<asp:DropDownList ID="ddlPartEquipmentNew" runat="server" DataSourceID="SqlDataSourcePartEquipment" DataValueField="EquipmentType" DataTextField="EquipmentType"
AppendDataBoundItems="True" Width="270px" Height="20px" Style="margin-left: 70px;">
<asp:ListItem Value="0">---SELECT---</asp:ListItem>
</asp:DropDownList>
<asp:DropDownList ID="ddlPartNew" runat="server" DataSourceID="SqlDataSourcePart" DataValueField="RecID"
DataTextField="description" AppendDataBoundItems="True" Width="270px" Height="20px"
style="margin-left: 70px; margin-right: 110px">
<asp:ListItem Value="0">---SELECT---</asp:ListItem>
</asp:DropDownList>
<asp:textbox ID="txtUnitPriceNew" runat="server" Width="95px"/>
<asp:textbox ID="txtTaxNew" runat="server" Width="95px" text="0"/>
<asp:Button ID="InsertDetail" runat="server" CommandName="InsertDetail" Height="25px" Text="Add Detail" Width="85px" />
</EmptyDataTemplate>
<AlternatingRowStyle BackColor="#CCCCCC" />
<Columns>
<asp:CommandField ShowEditButton="True" footertext="Add -->" ShowDeleteButton="True" HeaderStyle-Width="70px"/>
<asp:BoundField DataField="RecID" HeaderText="RecID" SortExpression="RecID" ReadOnly="True" Visible="False" />
<asp:TemplateField HeaderText="Parts Description" ItemStyle-HorizontalAlign="center">
<ItemTemplate>
<asp:label ID="lblDescriptionAdd" Text='<%# Bind("PartFailed") %>' runat="server"/>
</ItemTemplate>
<EditItemTemplate>
<asp:DropDownList ID="ddlPartEquipmentEdit" runat="server" DataValueField="Agreement" DataTextField="EquipmentType"
AppendDataBoundItems="True" Width="270px" Height="20px" Style="margin-left: 70px;">
<asp:ListItem Value="0">---SELECT---</asp:ListItem>
</asp:DropDownList>
<asp:DropDownList ID="ddlPartEdit" runat="server" DataSourceID="SqlDataSourcePart" DataValueField="RecID" DataTextField="description" SelectedValue='<%# Eval("RepairID")%>' AppendDataBoundItems="True" Width="270px"/>
</EditItemTemplate>
<FooterTemplate>
<asp:DropDownList ID="ddlPartEquipmentInsert" runat="server" DataValueField="Agreement" DataTextField="EquipmentType"
AppendDataBoundItems="True" Width="270px" Height="20px" Style="margin-left: 70px;">
<asp:ListItem Value="0">---SELECT---</asp:ListItem>
</asp:DropDownList>
<asp:DropDownList ID="ddlPartInsert" runat="server" DataSourceID="SqlDataSourcePart" DataValueField="RecID" DataTextField="description" AppendDataBoundItems="True" Width="270px">
<asp:ListItem Value="0">---SELECT---</asp:ListItem>
</asp:DropDownList>
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Part Cost Requested" ItemStyle-HorizontalAlign="center" HeaderStyle-Width="100px">
<ItemTemplate>
<asp:label ID="lblUnitPrice" Text='<%# Bind("PartCost", "{0:C}") %>' runat="server" Enabled="False"/>
</ItemTemplate>
<EditItemTemplate>
<asp:textbox ID="txtUnitPriceEdit" Text='<%# Bind("PartCost") %>' Enabled="true" runat="server"/>
</EditItemTemplate>
<FooterTemplate>
<asp:textbox ID="txtUnitPriceInsert" Text='<%# Bind("PartCost") %>' runat="server" style="width: 100%; box-sizing: border-box;"/>
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Tax" ItemStyle-HorizontalAlign="Center" HeaderStyle-Width="100px">
<ItemTemplate>
<asp:LinkButton ID="lbTaxTotal" Text='<%# Bind("Tax", "{0:C}")%>' runat="server" CommandArgument="Part" OnClick="lblTaxTotal_Click"/>
<asp:HiddenField ID="hidPartGST" runat="server" Value='<%# Bind("GST")%>' />
<asp:HiddenField ID="hidPartPST" runat="server" Value='<%# Bind("PST")%>' />
<asp:HiddenField ID="hidPartQST" runat="server" Value='<%# Bind("QST")%>' />
<asp:HiddenField ID="hidPartHST" runat="server" Value='<%# Bind("HST")%>' />
</ItemTemplate>
<EditItemTemplate>
<asp:textbox ID="lblTaxTotalEdit" Text='<%# Bind("Tax")%>' Enabled="true" runat="server"/>
</EditItemTemplate>
<FooterTemplate>
<asp:textbox ID="txtTaxTotalInsert" Text="0" runat="server" Enabled="true" style="width: 100%; box-sizing: border-box;"/>
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Insert New" HeaderStyle-Width="85px">
<ItemTemplate>
<asp:Label ID="lblEmpty" Text="" runat="server" Width="75px"/>
</ItemTemplate>
<FooterTemplate>
<asp:Button ID="Insert" runat="server" CommandName="InsertNewDetail" Height="22px" Text="Insert" style="width: 100%; box-sizing: border-box;" />
</FooterTemplate>
</asp:TemplateField>
</Columns>
<HeaderStyle BackColor="#336699" ForeColor="White" />
</asp:GridView>
In the above code, the gridview is declared and there are a series of controls within the gridview. The control in question is "ddlPartEquipmentNew" (technically I am having the same problem with the 2 other drop downs labeled "ddlPartEquipmentEdit" and "ddlPartEquipmentInsert" respectively, however we can ignore those at the moment.)
For whatever reason I cannot seem to figure out how to bind this ddl to the appropriate values I have in my database.
Below I will go into detail on what I have tried and the various outputs I have gotten.
One of the first things I have tried was to create a GetData() Function and then call that function in the gridviews OnDataBound() event, however when doing this, though I don't receive an error, the drop down has no values other than the default "---SELECT---" I setup in the aspx code above.
Below I have attached the code for the GetData() function and code for the OnDataBound() procedure.
GetData()
Private Function GetEquipmentData(query As String) As DataSet
Dim conString As SqlConnection = objCn
Dim cmd As New SqlCommand(query)
Using conString
Using sda As New SqlDataAdapter()
cmd.Connection = conString
sda.SelectCommand = cmd
Using ds As New DataSet()
sda.Fill(ds, txtAgreement.Text)
Return ds
End Using
End Using
End Using
End Function
OnDataBound()
Protected Sub GridView3_DataBound(sender As Object, e As EventArgs) Handles GridView3.DataBound
Dim partRequestedTotal As Decimal = Decimal.Zero
Dim partTotal As Decimal = Decimal.Zero
Dim gv As GridView = sender
If gv.EditIndex = -1 Then
For Each row As GridViewRow In gv.Rows
If row.RowType = DataControlRowType.DataRow Then
Dim lblAmount As Label = row.FindControl("lblUnitPrice")
Dim lblAmountRequested As Label = row.FindControl("lblUnitPrice")
Dim ddlPartEquipmentNew As DropDownList = row.FindControl("ddlPartEquipmentNew")
ddlPartEquipmentNew.DataSource = GetEquipmentData("SELECT EquipmentType FROM Equipment WHERE Agreement = #Agreement")
ddlPartEquipmentNew.DataTextField = "EquipmentType"
ddlPartEquipmentNew.DataValueField = "EquipmentType"
ddlPartEquipmentNew.DataBind()
'Dim lblMarkup As Label = row.FindControl("lblMarkup")
Dim partRequested As Decimal = Decimal.Parse(lblAmountRequested.Text, NumberStyles.Currency)
'Convert.ToDecimal(lblAmountRequested.Text.Replace("$", ""))
Dim partValue As Decimal = Decimal.Parse(lblAmount.Text, NumberStyles.Currency)
'Convert.ToDecimal(lblAmount.Text.Replace("$", ""))
'Dim markupValue As Decimal = Decimal.Parse(lblMarkup.Text, NumberStyles.Currency)
'Convert.ToDecimal(lblMarkup.Text.Replace("$", ""))
'partTotal = partValue + partTotal + markupValue
partRequestedTotal = partRequestedTotal + partRequested
End If
Next
'txtPartsTotal.Text = partTotal.ToString
txtPartsRequested.Text = partRequestedTotal.ToString("N2")
If GridView3.Rows.Count > 0 Or GridView1.Rows.Count > 0 Then
calculateTotalTax()
calculateTotal()
Else
txtTax.Text = "0"
Me.txtGrandTotal.Text = "0"
End If
End If
End Sub
With this attempt at binding the drop down list I receive no errors however the drop down in question remains empty.
I have also tried to create a databind event for the drop down list specifically and in the OnDataBind() event for the control I reference the procedure I created, however when I do this I get an exception error stating that I have a connection to the database that has not been closed, or a timeout exception.
Below is the code for the ddl databind event
Protected Sub DDLPartEquipmentNew_DataBind(sender As Object, e As EventArgs)
Dim ddlPartEquipmentNew As DropDownList = sender
Using con As New SqlConnection(ConfigurationManager.ConnectionStrings("WarrantyConnectionString").ToString)
Using cmd As New SqlCommand("SELECT EquipmentType FROM Equipment WHERE Agreement = #Agreement")
cmd.Parameters.Add("#Agreement", SqlDbType.Int).Value = txtAgreement.Text
cmd.CommandType = CommandType.Text
con.Open()
cmd.Connection = con
ddlPartEquipmentNew.DataSource = cmd.ExecuteReader()
ddlPartEquipmentNew.DataBind()
con.Close()
End Using
End Using
End Sub
As a last note on the situation I am having, the other drop down controls in this gridview are populated using an asp:SqlDataSource control which I have also tried, the issue I run into using a datasource in the aspx page is that my query requires a variable and so far I have not found a way to declare that variable in the code behind to avoid the exception "Must declare Scalar Variable #Agreement". The especially weird part about this exception is that in the stack trace it is popping this exception inside the databind event for a different gridview.
Query in question: SELECT EquipmentType FROM Equipment WHERE Agreement = #Agreement
Relatively simple, or at least I would think so. Any help someone would be able to offer on this problem would be greatly appreciated as I am at a loss as to how to populate this drop down, let alone any other drop down lists I may have to add to the page.