Cascading Dropdowns in EditFormTemplate

[Joe]

Hello, I am having an issue with a custom edit form for rad grid.  I have cascading drop downs in an edit form template, basically, user selects a state and then the city dropdown pre populates with cities in that state.  I bind the initial item lists in the ItemDataBound event like I saw in some examples.  I have no issues pre populating the drop downs with the initial lists and selected values, however if a user changes the value of the States drop down, it causes a postback (which it should) but it resets the whole form back to the original values.

<MasterTableView EditMode="PopUp" EditFormSettings-PopUpSettings-Width="600" DataKeyNames="Id">
<EditFormSettings EditFormType="Template"   >
<FormTemplate  >
<table cellspacing="8">
<tr>
<td class="style2">Title:</td>
<td>
    <telerik:RadTextBox ID="txtTitle" Visible="true" Text='<%# DataBinder.Eval( Container, "DataItem.Title" ) %>' MaxLength="100" Width="400" runat="server">
    </telerik:RadTextBox>
</td>
</tr>
<tr>
<td class="style1" valign="top" >State:</td>
<td>
    <telerik:RadComboBox ID="RadComboBoxState" runat="server">
    </telerik:RadComboBox>

</td>
</tr>
<tr>
<td class="style1" valign="top" >City:

</td>
<td>
    <telerik:RadComboBox ID="RadComboBoxCity" runat="server">
    </telerik:RadComboBox>

</td>
</tr>

protected void RadGrid1_ItemDataBound(object sender, Telerik.Web.UI.GridItemEventArgs e)
   {
       if (e.Item is GridEditFormItem && e.Item.IsInEditMode)
       {
           GridEditFormItem editFormItem = e.Item as GridEditFormItem;
           GridDataItem parentItem = editFormItem.ParentItem;

           Literal debug = (Literal)editFormItem.FindControl("ltr_debug");

           int _EntityId = Convert.ToInt32(parentItem["OwnerEntityId"].Text);

           //*******************************
           //Load states
           //*******************************
           RadComboBox cbStates = editFormItem.FindControl("RadComboBoxState") as RadComboBox;
           DataTable dtStates = ApplicationInterface.GetActiveStates();
           cbStates.DataSource = dtStates;
           cbStates.DataValueField = "id";
           cbStates.DataTextField = "name";
           cbStates.DataBind();
           cbStates.SelectedValue = parentItem["SelectedState"].Text;
           cbStates.AutoPostBack=true;
           cbStates.SelectedIndexChanged += new System.EventHandler(StateSelected);

           //*******************************
           //Load cities
           //*******************************
           RadComboBox lbCities= (RadComboBox)editFormItem.FindControl("RadComboBoxCity");
           DataTable dtCitiesByState = ApplicationInterface.GetCitiesForState(parentItem["SelectedState"].Text);
           lbCities.DataSource = dtCitiesByState;
           lbCities.AutoPostBack = true;
           lbCities.DataValueField = "id";
           lbCities.DataTextField = "name";
           lbCities.DataBind();
           lbCities.SelectedValue = parentItem["SelectedCity"].Text;

       }
   }

protected void StateSelected(object sender, EventArgs e)
{
   RadComboBox dc = (RadComboBox)sender;

   GridEditFormItem editedItem = dc.NamingContainer as GridEditFormItem;
   RadComboBox cities=editedItem.FindControl("RadComboBoxCity") as RadComboBox;
   ...
   ..Binding code here

 }

So the edit form populates correctly, user changes some text boxes etc... but if they select a different state the whole form resets.  Is there anything special I need to do to use cascading combo boxes with async postbacks in my edit form.  I have read some other posts but I cant find anything that replicates the issue I am having.

[Pavlina]

Hello Joe,

I recommend that you examine this code library which shows how to use related RadComboBoxes for Insert and Update operations in RadGrid.

I hope this gets you started properly.

Best wishes,
Pavlina
the Telerik team

[Joe]

Hi, I have reviewed this but the example provided uses edit columns.  I am trying to use and EditFormTemplate.  DO you have an example of cascading drop downs in an editformtemplate scenario.  Thanks

[Pavlina]

Hello Joe,

In this case, you can reference the cell(s) which hold the combo box control(s). For additional information on this topic, please refer to the following article:

http://www.telerik.com/help/aspnet-ajax/grdaccessingcellsandrows.html

I hope this gets you started properly.

Best wishes,
Pavlina
the Telerik team

[Lee]

Hi Joe,

You might have found a solution to this already but I thought it was worth posting a solution anyway. I have 2 Radcomboboxes, Locations and Warehourse. When a location is selected, the warehouses at that location are loaded.

I put a textbox on the form called CurrentLocation with visible set to false. I added the following code on the Locations SelectIndexChanged event:

protected void RadComboBox5_SelectedIndexChanged(object sender, RadComboBoxSelectedIndexChangedEventArgs e)
{
    if (RadGrid1.MasterTableView.IsItemInserted != false)
    {
        GridEditFormInsertItem insertItem = (GridEditFormInsertItem)(sender as RadComboBox).NamingContainer;
        RadComboBox ddlList = (RadComboBox)insertItem.FindControl("RadCombox5");
        CurrentLocation.Text = ddlList.SelectedValue ;
    }
    else
    {
        GridEditableItem editedItem = (GridEditableItem)(sender as RadComboBox).NamingContainer;
        RadComboBox ddlList = (RadComboBox)editedItem.FindControl("RadComboBox5");
        CurrentLocation.Text = ddlList.SelectedValue;
    }
}

The Location RadComboBox does an autopostback and the appropriate warehouses are loaded.

Regards, Lee

[Pavlina]

Hi Lee,

Thank you for sharing your solution with us and the community! It will certainly help other people searching similar functionality.

Kind regards,
Pavlina
the Telerik team