I found the following thread which is similar HERE and tried a few suggestions from there but still am not getting any data showing up.

I am new to Ext.net the company I am working for is using it and yes its still version 2, but here is what I am trying to accomplish:

  1. Select item from combo box
  2. On the select event grab the relevant data based on the selected value
  3. use selected data in separate combo box


Here is how I have setup the items in code:

// view

// data store
<ext:Store runat="server" ID="uxDistrictsStore">
    <Model>
        <ext:Model runat="server">
            <Fields>
                <ext:ModelField Name="NAME" />
                <ext:ModelField Name="ID" />
            </Fields>
        </ext:Model>
    </Model>
    <Proxy>
        <ext:PageProxy />
    </Proxy>
</ext:Store>

// 1st selection combo box
<ext:ComboBox runat="server" ID="uxBusinessUnits" LabelWidth="145" InputWidth="250"
    FieldLabel="Business Unit" DisplayField="NAME" ValueField="ID" AllowBlank="false"
    StoreID="uxBusinessUnitsStore" ForceSelection="true" QueryMode="local" TypeAhead="true">
    <DirectEvents>
        <Select OnEvent="deBusinessUnitsChanged"></Select>
    </DirectEvents>
    <Plugins>
        <ext:ClearButton runat="server" />
    </Plugins>
</ext:ComboBox>

// 2nd combo box
<ext:ComboBox runat="server" ID="uxDistricts" LabelWidth="145" InputWidth="250"
    FieldLabel="District" DisplayField="NAME" ValueField="ID" AllowBlank="false"
    StoreID="uxDistrictsStore" ForceSelection="true" QueryMode="local" TypeAhead="true">
    <Plugins>
        <ext:ClearButton runat="server" />
    </Plugins>
</ext:ComboBox>

// code behind - I have verified the data source is populated before being bound and there are no errors during binding
[DirectMethod]
protected void deBusinessUnitsChanged(object sender, EventArgs e)
{
    try
    {
        if (int.TryParse(uxBusinessUnits.SelectedItem.Value, out int currentBusinessUnitID))
        {
            using (Entities _context = new Entities())
            {
                uxDistrictsStore.DataSource = _context.LEADS_DISTRCITS.Where(w => w.BUSINESS_UNIT_ID == currentBusinessUnitID).OrderByDescending(o => o.ID).ToList();
                uxDistrictsStore.DataBind();
            }
        }
        else
        {
            X.Msg.Alert("Error", "Unable to load Districts data. Please try again later. If the issue persists, please contact IT.").Show();
        }
    }
    catch (Exception)
    {
        X.Msg.Alert("Error", "Unable to load Districts data. Please try again later. If the issue persists, please contact IT.").Show();
    }
}