CODEWITHSUNDEEP
c#razor
Shannon Hochkins
Shannon Hochkins

Reputation: 12175

Get property by dynamic key name?

I'm trying to avoid duplicating some templates, let's say I have the following (very simplified) template:

<div class="same-template">
    @(button?.buttonLeft.Url)
</div>
<div class="same-template">
    @(button?.buttonRight.Url)
</div>

I also have a button Right template as well, so my question is, is there a way I can pass in the "Side" of the button, and access the property? I know in javascript I'd do something like:

@(button?.button"+side+".Url) but obviously we're not using javascript.

I've tried creating a helper function

@helper GetFooter(Object button, String side) {
    <div class="same-template">
        <!-- don't know what to do here... -->
        @(button?.button<side>.Url)
    </div>
}

@GetFooter(button, "Right")

I hope this was clear enough!

EDIT: Ive made the following function, however on some it fails on the var b line with the following error:

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

@functions{

    public dynamic GetNestedDynamicValue(IContentCardItem cardItem, String first, String second) {
        var b = cardItem?.GetType().GetProperty(first).GetValue(cardItem, null);
        var c = b?.GetType().GetProperty(second).GetValue(b, null);
        return c;
    }
}

Upvotes: 1

Views: 369

Answers (1)

kat1330
kat1330

Reputation: 5332

C# is typed and doesn't provide functionalities like JavaScript. Anyway, you can try something like in follwoing example to dinamically read value of property by name:

<div>
    @(button?.GetType().GetProperty("PropertyNameWhichYouNeed").GetValue(button, null))
</div>

UPDATE:

Ok, I am think that you will need some extension method, but try first this:

button?.GetType().GetProperty("buttonRight").GetValue(button, null)
    .GetType().GetProperty("Url").GetValue(
button?.GetType().GetProperty("buttonRight").GetValue(button, null),
 null);

It became confusing :) I don't like this kind of UI but let try to explain:

Firs I retrieve type of buttonRight property. Then I retrieve type Url and supplied type of buttonRight instance.

It should be broken in following lines:

var buttonRight = button.GetType().GetProperty("buttonRight").GetValue(button, null);
var url = buttonRight.GetType().GetProperty("Url").GetValue(buttonRight, null);

Now url is value which you looking. Please see on fiddle how it works:

.NET Fiddle.

Upvotes: 1

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