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RadComboBox interact with other RadComboBox but selectedvalue is empty

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ComboBox

This is a migrated thread and some comments may be shown as answers.

jeslopmay asked on 24 Feb 2012, 02:08 PM

Hello,

I have several RadComboBoxes that interact with each other using client-side methods and requesting the items on demand, like here: http://demos.telerik.com/aspnet-ajax/combobox/examples/functionality/multiplecomboboxes/defaultcs.aspx
This works well, but when I need the SelectedValue it's always empty.

Can anyone help me please? (I don't know what I'm doing wrong...)

Here I put the code used:

RadComboBoxes

<telerik:RadComboBox ID="cboProvinciaT" runat="server" Width="200px" OnClientSelectedIndexChanging="LoadLocalidades" OnItemsRequested="cboProvinciaT_ItemsRequested" MarkFirstMatch="true" Skin="Sunset"></telerik:RadComboBox>

<telerik:RadComboBox ID="cboLocalidadT" runat="server" Width="200px" OnClientSelectedIndexChanging="LoadTiposVia" OnClientItemsRequested="ItemsLoaded" OnItemsRequested="cboLocalidadT_ItemsRequested" MarkFirstMatch="true" Skin="Sunset"></telerik:RadComboBox>

<telerik:RadComboBox ID="cboTipoViaT" runat="server" Width="80px" OnClientSelectedIndexChanged="LoadNombresVia" OnClientItemsRequested="ItemsLoaded" OnItemsRequested="cboTipoViaT_ItemsRequested" MarkFirstMatch="true" Skin="Sunset"></telerik:RadComboBox>

<telerik:RadComboBox ID="cboNombreVia" runat="server" OnClientItemsRequested="ItemsLoaded" OnItemsRequested="cboNombreVia_ItemsRequested" Filter="Contains" Skin="Sunset"></telerik:RadComboBox>

Scripts

<script type="text/javascript">

var LocalidadesCombo;

var TiposViaCombo;

var NombresVia;

function pageLoad() {

LocalidadesCombo = $find("<%= cboLocalidadT.ClientID %>");

TiposViaCombo = $find("<%= cboTipoViaT.ClientID %>");

NombresVia = $find("<%= cboNombreVia.ClientID %>");

}

function LoadLocalidades(sender, eventArgs) {

var item = eventArgs.get_item();

LocalidadesCombo.set_text("Cargando...");

TiposViaCombo.clearSelection();

if (item.get_index() > 0) {

LocalidadesCombo.requestItems(item.get_value(), false);

LocalidadesCombo.clearSelection();

}

else {

LocalidadesCombo.set_text(" ");

LocalidadesCombo.clearItems();

TiposViaCombo.set_text(" ");

TiposViaCombo.clearItems();

}

function LoadTiposVia(sender, eventArgs) {

var item = eventArgs.get_item();

TiposViaCombo.set_text("Cargando...");

TiposViaCombo.requestItems(item.get_value(), false);

TiposViaCombo.clearSelection();

if (item.get_index() > 0) {

TiposViaCombo.requestItems(item.get_value(), false);

TiposViaCombo.clearSelection();

}

else {

TiposViaCombo.set_text(" ");

TiposViaCombo.clearItems();

NombresVia.set_text(" ");

NombresVia.clearItems();

}

function LoadNombresVia(sender, eventArgs) {

var item = eventArgs.get_item();

NombresVia.set_text("Cargando...");

NombresVia.requestItems(item.get_value(), false);

NombresVia.clearSelection();

}

function ItemsLoaded(sender, eventArgs) {

sender.showDropDown();

}

</script>

Page_Load (server-side)

if (!Page.IsPostBack)

{

CargarProvincias(); //This method fill cboProvinciaT

}

else if (!Page.IsCallback)

{

LoadLocalidades(cboProvinciaT.SelectedValue);

LoadTiposVia(cboLocalidadT.SelectedValue);

LoadNombresVia(cboTipoViaT.SelectedValue);

}

Rest of functions

#region Dirección

protected void LoadLocalidades(string pIdProvincia)

{

try

{

AD.Motor mMotorAD = new AD.Motor();

DataTable mDT = new DataTable();

mDT = mMotorAD.ExecuteDataTable("Select 0 as ID, 'Localidad...' as Nombre union SELECT ID, Nombre FROM tlLocalidadDN where idProvincia=" + pIdProvincia + " ORDER BY Nombre ASC");

DataSet mDS = new DataSet();

mDS.Tables.Add(mDT);

cboLocalidadT.DataTextField = "Nombre";

cboLocalidadT.DataValueField = "ID";

cboLocalidadT.DataSource = mDS.Tables[0];

cboLocalidadT.DataBind();

}

catch (Exception ex)

{

throw ex;

}

protected void LoadTiposVia(string pIdLocalidad)

{

try

{

AD.Motor mMotorAD = new AD.Motor();

DataTable mDT = new DataTable();

mDT = mMotorAD.ExecuteDataTable("Select 0 as ID, 'Vía..' as Nombre union SELECT ID, Nombre FROM tlTipoViaDN ORDER BY Nombre ASC");

DataSet mDS = new DataSet();

mDS.Tables.Add(mDT);

cboTipoViaT.DataTextField = "Nombre";

cboTipoViaT.DataValueField = "ID";

cboTipoViaT.DataSource = mDS.Tables[0];

cboTipoViaT.DataBind();

}

catch (Exception ex)

{

throw ex;

}

protected void LoadNombresVia(string pIdTipoVia)

{

try

{

//HERE ALWAYS GET empty ("") string mIdLocalidad = cboLocalidadT.SelectedValue;

AD.Motor mMotorAD = new AD.Motor();

DataTable mDT = new DataTable();

mDT = mMotorAD.ExecuteDataTable("Select 0 as ID, ' Nombre de la Vía..' as Nombre union SELECT ID, Nombre FROM tlViaDN where idLocalidad=" + mIdLocalidad + " and idTipovia=" + pIdTipoVia + " order by Nombre");

DataSet mDS = new DataSet();

mDS.Tables.Add(mDT);

cboNombreVia.DataTextField = "Nombre";

cboNombreVia.DataValueField = "ID";

cboNombreVia.DataSource = mDS.Tables[0];

cboNombreVia.DataBind();

}

catch (Exception ex)

{

throw ex;

}

protected void LoadNombresVia(string pIdTipoVia, string pIdLocalidad)

{

try

{

AD.Motor mMotorAD = new AD.Motor();

DataTable mDT = new DataTable();

mDT = mMotorAD.ExecuteDataTable("Select 0 as ID, ' Nombre de la Vía..' as Nombre union SELECT ID, Nombre FROM tlViaDN where idLocalidad=" + pIdLocalidad + " and idTipovia=" + pIdTipoVia + " order by Nombre");

DataSet mDS = new DataSet();

mDS.Tables.Add(mDT);

cboNombreVia.DataTextField = "Nombre";

cboNombreVia.DataValueField = "ID";

cboNombreVia.DataSource = mDS.Tables[0];

cboNombreVia.DataBind();

}

catch (Exception ex)

{

throw ex;

}

protected void cboNombreVia_ItemsRequested(object o, RadComboBoxItemsRequestedEventArgs e)

{

LoadNombresVia(e.Text);

}

protected void cboProvinciaT_ItemsRequested(object o, RadComboBoxItemsRequestedEventArgs e)

{

CargarProvincias();

}

protected void cboLocalidadT_ItemsRequested(object o, RadComboBoxItemsRequestedEventArgs e)

{

LoadLocalidades(e.Text);

}

protected void cboTipoViaT_ItemsRequested(object o, RadComboBoxItemsRequestedEventArgs e)

{

LoadTiposVia(e.Text);

}

#endregion

When I try to get cboLocalidadT.SelectedValue in function LoadNombresVia

protected void LoadNombresVia(string pIdTipoVia)

{

try

{

//********************************************

//**** HERE ALWAYS GET EMPTY VALUE --> "" ****

//********************************************

string mIdLocalidad = cboLocalidadT.Text;

//********************************************

AD.Motor mMotorAD = new AD.Motor();

DataTable mDT = new DataTable();

DataSet mDS = new DataSet();

mDS.Tables.Add(mDT);

cboNombreVia.DataTextField = "Nombre";

cboNombreVia.DataValueField = "ID";

cboNombreVia.DataSource = mDS.Tables[0];

cboNombreVia.DataBind();

}

catch (Exception ex)

{

throw ex;

}

Thank you very much for your help!!

4 Answers, 1 is accepted

Accepted

answered on 28 Feb 2012, 03:43 PM

Hello Guys,

The reason for the experienced behavior is the following. When the ItemsRequested event is fired a callback to the server is made and not a regular post-back. The important part in this case is the fact that the current state of the controls on the page is not send to the server and therefore you could not get the SelectedValue of your second combobox. In the event handler function you could only access the data from the event arguments. If you want to pass the selected value of the second combobox you should add it to the context object as show in the following help article here.

Greetings,
Dimitar Terziev
the Telerik team

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answered on 28 Feb 2012, 07:12 PM

Thank you SO much to both!

At finally worked fine using the context object.

Adds to my code to show it running:

RadComboBox --> cboNombreVia

Add this property:

OnClientItemsRequesting="GetSelectedItem"

new function

function GetSelectedItem(sender, eventArgs) {

var LocalidadCombo = $find("<%= cboLocalidadT.ClientID %>");

var LocalidadText = LocalidadCombo.get_text();

var context = eventArgs.get_context();

context["Localidad"] = LocalidadText;

}

Thank you very much again for answering my question.

Greetings,
Jeslopmay