CODEWITHSUNDEEP
asp.netasp.net-core.net-coreasp.net-core-mvcmodel-binding
Scotty.NET
Scotty.NET

Reputation: 12580

How to combine usage of asp-all-route-data and a list of ids in query string

In ASP.NET, asp-all-route-data is great for passing variables into an anchor tag. But now I am trying to add a list of ids and not having much luck. asp-all-route-data accepts an IDictionary<string, string> which cannot have duplicate keys. But I need to bind to a list from query string such as ?myParams=1&myParams=2 (as dictated by ASP.NET out of the box model binding).

var myParams = new List<int> {0,1,2};
var routeData = new Dictionary<string, string>();
foreach (var myParam in myParams)
{
  routeData.Add(nameof(myParams), myParam.ToString());
}

I tried adding results in duplicate key exception.

var myParams = new List<int> {0,1,2};
var routeData = new Dictionary<string, string>();
for (var i = 0; i < myParams.Count; i++)
{
  var myParam = myParams[i];
  routeData.Add($"{nameof(myParams)}{i}", myParam.ToString());
}

results in no model binding.

Here's the razor for completeness:

<a asp-route="@routeName" asp-all-route-data="@routeData">click me</a>

Upvotes: 3

Views: 1187

Answers (1)

Scotty.NET
Scotty.NET

Reputation: 12580

While researching the question further I actually found the answer, so will share it here.

It turns out I was quite close, but rather than a naming convention of

$"{nameof(myParams)}{i}"

It should have been

$"{nameof(myParams)}[{i}]"

as detailed in the Microsoft documentation for model binding.

Full code example:

var myParams = new List<int> {0,1,2};
var routeData = new Dictionary<string, string>();
for (var i = 0; i < myParams.Count; i++)
{
  var myParam = myParams[i];
  routeData.Add($"{nameof(myParams)}[{i}]", myParam.ToString());
}

Which results in a query string (based on the route I have set up) of:

?myParams[0]=0&myParams[1]=1&myParams[2]=2

Upvotes: 4

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