How to declare in the View?

Question

How to declare in the View?
@{
var kvp = ViewData["kvp"] as KeyValuePair<int, string>[]>;
}

Answer 1

Your KeyValuePair syntax is incorrect so I'm not sure of the exact code. The cast syntax is either...

@{  
    var kvp = (KeyValuePair<int, string>)ViewData["kvp"];  
}  

...or...

@{  
    var kvp = (KeyValuePair<int, string[]>)ViewData["kvp"];  
}  

Casting and type conversions (C# Programming Guide)

Answer 2

try (assuming it is an array of KeyValuePairs, often its an IEnumable instead) :

@{ 
    var kvp = ViewData["kvp"] as KeyValuePair<int, string>[]; 
}

Answer 3

There is an error with your both suggestions: "'KeyValuePair' is 'type' and not valid in the given context."

Keep in mind it is very difficult to provide an accurate solution when you post code with compiler errors. I have no idea what your intention is.

Anyway, from your response it seems you are passing a collection of key value pairs.

@{
    var kvp = ViewData["kvp"] as KeyValuePair<int, string>[];
}

Or

@{
    var kvp = (KeyValuePair<int, string>[])ViewData["kvp"];
}

I typically take advantage of List<T>.

@{
    var kvp = (List<KeyValuePair<int, string>>)ViewData["kvp"];
}

Answer 4

Dear @AgaveJoe , unfortunately, all your suggestions are unrecognizable ! Please don't reply without testing it !

I did test code before posting. Most likely there are other issues with your code and design that we cannot see. You only showed us one line of code and that line does not even compile. I'm sure there many other hidden gems in your source code.

[HttpGet]  
public IActionResult Index()  
{  
    KeyValuePair<int, string>[] values = new KeyValuePair<int, string>[]  
    {  
        new KeyValuePair<int, string>(1, "Hello"),  
        new KeyValuePair<int, string>(2, "World")  
    };  
  
    ViewData["kvp"] = values;  
    return View();  
}  

View

@{  
    ViewData["Title"] = "Index";  
    var kvp = (KeyValuePair<int, string>[])ViewData["kvp"];  
}  
  
<h1>Index</h1>  
  
<div>  
    @foreach (var item in kvp)  
    {  
        <div>  
            @item.Key: @item.Value  
        </div>  
    }  
</div>  

Answer 5

Hi @S A ,

var kvp = ViewData["kvp"] as KeyValuePair<int, string>[]>;    

The above code is correct, please check this result:

When loop through the data, it is better to check whether the data is null or not. More detail information about the view, you can refer the following tutorial:

Views in ASP.NET Core MVC

Razor syntax reference for ASP.NET Core

At the end, if I misunderstand about your problem, please feel free let me know and share the detailed question and code and the error message.

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Best regards,
Dillion