How do I construct a RouteValueDictionary when a route has multiple values?
I am creating a reusable method that validates my model and automatically generates urls (via ActionLink
) for swap. One of the properties of my model is string[]
(for a multi-select picklist), which is fully valid. Example URL-address: https://example.com?user=Justin&user=John&user=Sally
.
However, as the name indicates the type of RouteValueDictionary
implements IDictionary
, so it can not take the same key more than once.
var modelType = model.GetType();
var routeProperties = modelType.GetProperties().Where(p => Attribute.IsDefined(p, typeof(PagingRouteProperty)));
if (routeProperties != null && routeProperties.Count() > 0) {
foreach (var routeProperty in routeProperties) {
if (routeProperty.PropertyType == typeof(String)) {
routeDictionary.Add(routeProperty.Name, routeProperty.GetValue(model, null));
}
if (routeProperty.PropertyType == typeof(Boolean?)) {
var value = (Boolean?)routeProperty.GetValue(model, null);
routeDictionary.Add(routeProperty.Name, value.ToString());
}
//The problem occurs here!
if (routeProperty.PropertyType == typeof(string[])) {
var value = (string[])routeProperty.GetValue(model);
foreach (var v in value) {
routeDictionary.Add(routeProperty.Name, v);
}
}
}
//Eventually used here
var firstPageRouteDictionary = new RouteValueDictionary(routeDictionary);
firstPageRouteDictionary.Add("page", 1);
firstPageListItem.InnerHtml = htmlHelper.ActionLink("«", action, controller, firstPageRouteDictionary, null).ToHtmlString();
What can I use to create routes when the key is needed multiple times?
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You just need to specify the property name along with the index as Key
:
if (routeProperty.PropertyType == typeof(string[])) {
var value = (string[])routeProperty.GetValue(model);
for (var i = 0; i < value.Length; i++) {
var k = String.Format("{0}[{1}]", routeProperty.Name, i);
routeDictionary.Add(k, value[i]);
}
}
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Just try to imagine what the link will look like and it should make sense
new RouteValueDictionary { { "name[0]", "Justin" }, { "name[1]", "John" }, { "name[2]", "Sally" } }
which will generate the following query string
Coded
?name%5B0%5D=Justin&name%5B1%5D=John&name%5B3%5D=Sally
decoded
?name[0]=Justin&name[1]=John&name[3]=Sally
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