Programmatic two way databinding Combobox

[Trent]

Hello,

I have a bit of an issue:

I have four ComboBoxes on the page as seen below:

<telerik:RadAjaxManagerProxy ID="RadAjaxManagerProxy1" runat="server">
    <AjaxSettings>
        <telerik:AjaxSetting AjaxControlID="ddlCountry">
            <UpdatedControls>
                <telerik:AjaxUpdatedControl ControlID="ddlState" UpdatePanelHeight="" />
            </UpdatedControls>
        </telerik:AjaxSetting>
        <telerik:AjaxSetting AjaxControlID="ddlState">
            <UpdatedControls>
                <telerik:AjaxUpdatedControl ControlID="ddlLocation" UpdatePanelHeight="" />
            </UpdatedControls>
        </telerik:AjaxSetting>
        <telerik:AjaxSetting AjaxControlID="ddlLocation">
            <UpdatedControls>
                <telerik:AjaxUpdatedControl ControlID="ddlPostcode" UpdatePanelHeight="" />
            </UpdatedControls>
        </telerik:AjaxSetting>
    </AjaxSettings>
</telerik:RadAjaxManagerProxy>


                    <table id="Table1" width="100%" class="style1">
                        <tr runat="server" width="150px" id="tr10">
                            <td>
                                Country
                            </td>
                            <td>
                                <telerik:RadComboBox ID="ddlCountry" runat="server" OnSelectedIndexChanged="ddlCountry_SelectedIndexChanged"
                                    Width="300px" EnableLoadOnDemand="True" AutoPostBack="True">
                                </telerik:RadComboBox>
                                <asp:RequiredFieldValidator ID="rfvCountry" runat="server" ErrorMessage="*" ControlToValidate="ddlCountry"
                                    ValidationGroup="Customer"></asp:RequiredFieldValidator>
                            </td>
                        </tr>
                        <tr runat="server" id="trState">
                            <td>
                                State
                            </td>
                            <td>
                                <telerik:RadComboBox ID="ddlState" OnSelectedIndexChanged="ddlState_SelectedIndexChanged"
                                    Width="300px" runat="server" AutoPostBack="True">
                                </telerik:RadComboBox>
                                <asp:RequiredFieldValidator ID="rfvState" runat="server" ErrorMessage="*" ControlToValidate="ddlState"
                                    ValidationGroup="Customer"></asp:RequiredFieldValidator>
                            </td>
                            <td>
                                Location
                            </td>
                            <td>
                                <telerik:RadComboBox ID="ddlLocation" OnSelectedIndexChanged="ddlLocation_SelectedIndexChanged"
                                    Width="300px" runat="server" AutoPostBack="True">
                                </telerik:RadComboBox>
                                <asp:RequiredFieldValidator ID="rfvLocation" runat="server" ErrorMessage="*" ControlToValidate="ddlLocation"
                                    ValidationGroup="Customer"></asp:RequiredFieldValidator>
                            </td>
                        </tr>
                        <tr runat="server" id="trPostcode">
                            <td>
                                Postcode
                            </td>
                            <td>
                                <telerik:RadComboBox ID="ddlPostcode" runat="server" Width="300px">
                                </telerik:RadComboBox>
                                <asp:RequiredFieldValidator ID="rfvPostcode" runat="server" ErrorMessage="*" ControlToValidate="ddlPostcode"
                                    ValidationGroup="Customer"></asp:RequiredFieldValidator>
                            </td>
                        </tr>
                    </table>

all data-bound from c# like so (including selected index changed);

#region Location ddls
private void BindCountry()
{
    string sql = "SELECT DISTINCT LookupID_LookupTable, LookupID, LookupParentID FROM " + XDEV.xd_Schema.ToString() + "xd_lookup_tables WHERE (LookupParentID = 41)";
    DataTable dt = data.GetDataTable(sql);
    if (dt.Rows.Count > 0)
    {
        ddlCountry.DataSource = dt;
        ddlCountry.DataTextField = "LookupID_LookupTable";
        ddlCountry.DataValueField = "LookupID";
        ddlCountry.DataBind();
        //RadAjaxManager1.FocusControl(ddlCountry);
    }
}
private void BindState(string country)
{
    string sql = string.Format("SELECT DISTINCT LookupID_LookupTable, LookupID, LookupParentID FROM " + XDEV.xd_Schema.ToString() + "xd_lookup_tables WHERE ( LookupID_ParentLookupID ={0})", country);
    DataTable dt = data.GetDataTable(sql);
    if (dt.Rows.Count > 0)
    {
        ddlState.DataSource = dt;
        ddlState.DataTextField = "LookupID_LookupTable";
        ddlState.DataValueField = "LookupID";
        ddlState.DataBind();
        //RadComboBoxItem StateItem = new RadComboBoxItem("- Select a State -", "0"); //Creates new item for RadCombobox
        //ddlState.Items.Add(StateItem);
    }
}
private void BindLocation(string state)
{
    string sql = string.Format("SELECT DISTINCT LookupID_LookupTable, LookupID, LookupParentID FROM " + XDEV.xd_Schema.ToString() + "xd_lookup_tables WHERE ( LookupID_ParentLookupID = {0})", state);
    DataTable dt = data.GetDataTable(sql);
    if (dt.Rows.Count > 0)
    {
        ddlLocation.DataSource = dt;
        ddlLocation.DataTextField = "LookupID_LookupTable";
        ddlLocation.DataValueField = "LookupID";
        ddlLocation.DataBind();
        //RadComboBoxItem LocationItem = new RadComboBoxItem("- Select a Location -", "0"); //Creates new item for RadCombobox
        //ddlLocation.Items.Add(LocationItem);
    }
}
private void BindPostcode(string location)
{
    string sql = string.Format("SELECT DISTINCT LookupID_LookupTable, LookupID, LookupParentID FROM " + XDEV.xd_Schema.ToString() + "xd_lookup_tables WHERE ( LookupID_ParentLookupID = {0})", location);
    DataTable dt = data.GetDataTable(sql);
    if (dt.Rows.Count > 0)
    {
        ddlPostcode.DataSource = dt;
        ddlPostcode.DataTextField = "LookupID_LookupTable";
        ddlPostcode.DataValueField = "LookupID";
        ddlPostcode.DataBind();
        //RadComboBoxItem PostcodeItem = new RadComboBoxItem("- Select a Postcode -", "0"); //Creates new item for RadCombobox
        //ddlPostcode.Items.Add(PostcodeItem);
    }
}

protected void ddlCountry_SelectedIndexChanged(object sender, EventArgs e)
{
    BindState(ddlCountry.SelectedValue);
}

protected void ddlState_SelectedIndexChanged(object sender, EventArgs e)
{
    BindLocation(ddlState.SelectedValue);
}
protected void ddlLocation_SelectedIndexChanged(object sender, EventArgs e)
{
    BindPostcode(ddlLocation.SelectedValue);
}
#endregion

and the existing records are bound like so:

#region cascading ddls
if (!String.IsNullOrEmpty(dt.Rows[0]["LookupID_Country"].ToString()))
{
    if (ddlCountry.Items.Contains(ddlCountry.Items.FindItemByValue(dt.Rows[0]["LookupID_Country"].ToString())))
    {
        ddlCountry.SelectedValue = dt.Rows[0]["LookupID_Country"].ToString();
        BindCountry();
    }
}
if (!String.IsNullOrEmpty(dt.Rows[0]["LookupID_State"].ToString()))
{
    if (ddlState.Items.Contains(ddlState.Items.FindItemByValue(dt.Rows[0]["LookupID_State"].ToString())))
    {
        ddlState.SelectedValue = dt.Rows[0]["LookupID_State"].ToString();
        BindState(ddlCountry.SelectedValue);
    }
    else
    {

    }
}
if (!String.IsNullOrEmpty(dt.Rows[0]["LookupID_Location"].ToString()))
{
    if (ddlLocation.Items.Contains(ddlLocation.Items.FindItemByValue(dt.Rows[0]["LookupID_Location"].ToString())))
    {
        ddlLocation.SelectedValue = dt.Rows[0]["LookupID_Location"].ToString();
        BindLocation(ddlState.SelectedValue);
    }
}
if (!string.IsNullOrEmpty(dt.Rows[0]["LookupID_Postcode"].ToString()))
{
    if (ddlPostcode.Items.Contains(ddlPostcode.Items.FindItemByValue(dt.Rows[0]["LookupID_Postcode"].ToString())))
    {
        ddlPostcode.SelectedValue = dt.Rows[0]["LookupID_Postcode"].ToString();
        BindPostcode(ddlLocation.SelectedValue);
    }
}
#endregion);

what is currently occurring is the first ComboBox is being bound with the record but the other 3  are blank where they should display the records from the db.

What needs to happen is when the user clicks 'Edit' button the user control becomes visible with ComboBoxes displaying the existing(non-edited data) and allow the user to change the ComboBox selected value.

[Trent]

Hello!!!!!,

is there any one answering the Telerik forums??? time is running out

[Dimitar Terziev]

Hello Trent,

Your code seems to be correct and the only reason for this problem is because the condition is not fulfilled:

if (!String.IsNullOrEmpty(dt.Rows[0]["LookupID_State"].ToString()))
{
    if (ddlState.Items.Contains(ddlState.Items.FindItemByValue(dt.Rows[0]["LookupID_State"].ToString())))
    {
        ddlState.SelectedValue = dt.Rows[0]["LookupID_State"].ToString();
        BindState(ddlCountry.SelectedValue);
    }
    else

If the condition fails the related ComboBoxes are not bound and thus you end up with no items.
When this happens you can't use SelectedIndexChanged event of the first RadComboBox because of the RequiredFiledValidators.
The page could not postback because the other RadComboBoxes have no items.

Greetings,
Dimitar Terziev
the Telerik team

[Trent]

so how do I get the desired result?

[Dimitar Terziev]

Hello Trent,

In order to troubleshoot this issues place a break point inside the "if"  statement clause. If the condition is not fulfilled then there is not such item:

ddlState.Items.Contains(ddlState.Items.FindItemByValue(dt.Rows[0]["LookupID_State"].ToString()))

On other hand, if the condition is fulfilled and the "State" RadComboBox is data bound, then we would try to find another way to troubleshoot the problem

Regards,
Dimitar Terziev
the Telerik team

[Trent]

Hello Dimitar Terziev,

Sorry for the delayed response... I was called away to work on another project that grew to be a bigger pain than foreseen.. I will black the breakpoint  and report back with the results.