DropDownListFor with ServerFiltering(true) and Initialization value

[Robert Madrian]

Hello,

If I use a DropDownListFor with ServerFiltering(true) there is no Initialization value - the DropDownList is always empty?

I use this DropDownListFor in a grid Editor template:

@(Html.Kendo().DropDownListFor(m => m.Mitglied_IDVerpaechter)
                                  .MinLength(1)
                                  .Height(400)
                                  .OptionLabel(" ").OptionLabelTemplate(" ")
                                  .DataTextField("Firmenbezeichnung")
                                  .Filter("contains")
                                  .NoDataTemplate("Keine Datensätze gefunden")
                                  .DataValueField("Mitglied_ID")
                                  .DataSource(dataSource =>
                                  {
                                      dataSource.Read(read => read.Action("Search", "Home", new { Area = "Mitglied" }).Type(HttpVerbs.Post))
                                          .ServerFiltering(true);
                                  })
                                  )

 

How to use ServerFiltering and also have a initialization value?

robert

 

[Dimitar]

Hello Robert,

I am attaching an ASP.NET Core solution, where a similar scenario to the one described is demonstrated (Kendo DropDownList inside a Grid editor template).

With it, the DropDownList is correctly bound to the ViewModel. If you try to change the value of the dropdown, you will notice that the foreign key column of the Grid is also updated accordingly.

In addition to the above, in the custom editor template, the initial value of the dropdown is set by using the DropDownList's value() method. 

Regards,
Dimitar
Progress Telerik

[Robert Madrian]

Hello,

it seems that my Problem is a little bit different - if I open my edit form the dropdownlist is empty because it only display entries if a search term is inserted because it searches in a tabel with a lot of rows
the dropdownlist is bound to a field of the model and is used in an grid edit template.
but there is no value in the dropdownlist if I open the form - it seems I have to search for the value first?

How to do this?

robert

[Dimitar]

Hello Robert,

You can use the DataSource's Data() method to send your search term as an additional parameter to the controller. Then you can query your database and build a collection depending on the value of the search term and return this collection as JSON. This way the DataSource of the widget will populate based on your special requirement. 

You can review a similar scenario in the following DropDownList demo. You will notice that the second DropDownList passes as an additional parameter the value of the previous widget. Then in the controller, it performs a query, which filters the database result based on the additional parameter and returns it to the view. 

I hope this helps you to resolve the issue.

Regards,
Dimitar
Progress Telerik

[Robert Madrian]

Hello Dimitar,

I have solved it in a similar way - thanks for pointing me in the right direction...

$("#grdPacht_" + berechtigungid).data("kendoGrid").bind("edit", function (e) {
            var model = e.model;
            var ddlMitglied_IDPaechter = $("#Mitglied_IDPaechter").getKendoDropDownList();
            var ddlMitglied_IDVerpaechter = $("#Mitglied_IDVerpaechter").getKendoDropDownList();

            GpdbHelpers.kendoDropDownList.reload("#Mitglied_IDPaechter", function () { return { text: model.Mitglied_IDPaechter } });
            GpdbHelpers.kendoDropDownList.reload("#Mitglied_IDVerpaechter", function () { return { text: model.Mitglied_IDVerpaechter } });

            ddlMitglied_IDPaechter.bind("filtering", function (e) {
                if (e.filter.value) {
                    GpdbHelpers.kendoDropDownList.reload("#Mitglied_IDPaechter", function() { return { text: e.filter.value } });
                }
            });
            ddlMitglied_IDVerpaechter.bind("filtering", function (e) {
                if (e.filter.value) {
                    GpdbHelpers.kendoDropDownList.reload("#Mitglied_IDVerpaechter", function () { return { text: e.filter.value } });
                }
            });
        });