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MultiSelectFor and ListView Binding

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Ant
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Ant asked on 19 May 2014, 06:19 PM
Hi

I have an issue when binding both a MultiSelecr and ListView to the same properties in a ViewModel but in different views. Here is an example:

In my ViewModel I have the following public properties

//Select List of all cars
 
public IEnumerable<System.Web.Mvc.SelectListItem> AllCars
        {
            get
            {
                if (Cars != null)
                {
                    var _sacts = Cars.Select(f => new System.Web.Mvc.SelectListItem
                    {
                        Value = f.code,
                        Text = f.description
                    });
                    return _sacts;
                }
                else return null;
            }
        }
 
public IEnumerable<CarTypes> Cars { get; set; }
 
//Select List of previous saved cars
 
public IEnumerable<System.Web.Mvc.SelectListItem> SelectedCars
        {
            get
            {
                if (SelectedCarsValues != null)
                {
                    var _sacts = SelectedCarsValues.Select(f => new System.Web.Mvc.SelectListItem
                    {
                        Value = f.code,
                        Text = f.description
                    });
                    return _sacts;
                }
                else return null;
            }
        }
 
public IEnumerable<CarTypes> SelectedCarsValues { get; set; }

Cars and SelectedCarsValues are populated from a db context.

On one view i have my MultiSelect

@(Html.Kendo().MultiSelectFor(m => m.SelectedCars)
    .BindTo(Model.AllCars)
    .DataTextField("Text")
    .DataValueField("Value")
)

And on another view I have my ListView

<script type="text/x-kendo-tmpl" id="CarsTemplate">
    ${Text}
</script>
 
@(Html.Kendo().ListView(Model.SelectedCars)
    .Name("Cars")
    .TagName("p")
    .ClientTemplateId("CarsTemplate")
    .BindTo(Model.SelectedCars)
)

This all works fine. But when i submit the form containing my multiselect the validation fails (ModelState.isvalid) as it is trying to convert a selecteditem to a string. So what i did was change my ViewModel for SelectedCars to be an IEnumerable<string> instead:

public IEnumerable<string> SelectedCars
{
    get
    {
        if (SelectedCarsValues != null)
        {
            return SelectedCarsValues.Select(a => a.code);
        }
        else return null;
 
    }
}

Now when i submit my form with the multiselect the validation passes. Yet, when i use my view i now have [object][object] showing as my ListView. I can change this to ${data} but it obviously only shows the code and not the description.

Therefore. How can i reuse the public properties from my ViewModel for both the MultiSelect and Listview without causing validation to fail when the MultiSelect is submitted? Or, am i binding either the MultiSelect or ListView (or both) incorrectly. Note that the Listview is not within a form and is not submitted to the controller.

Thanks for taking the time to have a look at this for me.

Anthony

3 Answers, 1 is accepted

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Ant
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answered on 20 May 2014, 08:06 AM
Here is the ModelState.IsValid error message when using a SelectListItem in the MultiSelect

""The parameter conversion from type 'System.String' to type 'System.Web.Mvc.SelectListItem' failed because no type converter can convert between these types."
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Petur Subev
Telerik team
answered on 21 May 2014, 12:37 PM
Hello Ant,

What you shared looks correct, the only code that bothers me is the get and set methods with the C# logic. Could you replace them with regular get and set methods and see if it makes a difference?

I saw this post:

http://forums.asp.net/t/1715908.aspx?Message+The+parameter+conversion+from+type+System+String+to+type+System+Web+Mvc+SelectListItem+failed+because+no+type+converter+can+convert+between+these+types+

Still it is not clear what might be the case. If still struggling put this in a small demo so we can search for the root of the exception.

Kind Regards,
Petur Subev
Telerik
 

Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.

 
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Ant
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answered on 31 May 2014, 10:52 AM
Hi, I never managed to get the ListView and DropDownList to share the same properties in the end successfully. Either one wouldn't display correctly or the ModelState was invalid. But i did manage to get it working using two different properties derived from the same list. I'm happy with this so thanks for your help.
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Petur Subev
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